''Phoenix'' was an uncrewed space probe that landed on the surface of
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
on May 25, 2008, and operated until November 2, 2008.
''Phoenix'' was operational on Mars for
sols (
days
A day is the time period of a full rotation of the Earth with respect to the Sun. On average, this is 24 hours, 1440 minutes, or 86,400 seconds. In everyday life, the word "day" often refers to a solar day, which is the length between two solar ...
). Its instruments were used to assess the local
habitability
Habitability refers to the adequacy of an environment for human living. Where housing is concerned, there are generally local ordinances which define habitability. If a residence complies with those laws it is said to be habitable. In extreme e ...
and to research the history of
water on Mars
Almost all water on Mars today exists as ice, though it also exists in small quantities as vapor in the atmosphere. What was thought to be low-volume liquid brines in shallow Martian soil, also called recurrent slope lineae, may be grains of f ...
. The mission was part of the
Mars Scout Program
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin atmosp ...
; its total cost was $420 million, including the cost of launch.
The multi-agency program was led by the
Lunar and Planetary Laboratory
The Lunar and Planetary Laboratory (LPL) is a research center for planetary science located in Tucson, Arizona. It is also a graduate school, constituting the Department of Planetary Sciences at the University of Arizona. LPL is one of the wo ...
at the
University of Arizona
The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory.
T ...
, with project management by
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
's
Jet Propulsion Laboratory
The Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, United States.
Founded in the 1930s by Caltech researchers, JPL is owned by NASA an ...
. Academic and industrial partners included universities in the United States, Canada, Switzerland, Denmark, Germany, the United Kingdom, NASA, the
Canadian Space Agency
The Canadian Space Agency (CSA; french: Agence spatiale canadienne, ASC) is the national space agency of Canada, established in 1990 by the ''Canadian Space Agency Act''.
The president is Lisa Campbell, who took the position on September 3, 2020 ...
, the
Finnish Meteorological Institute
The Finnish Meteorological Institute (FMI; fi, Ilmatieteen laitos; sv, Meteorologiska institutet) is the government agency responsible for gathering and reporting weather data and forecasts in Finland. It is a part of the Ministry of Transport ...
,
Lockheed Martin Space Systems
Lockheed Martin Space is one of the four major business divisions of Lockheed Martin. It has its headquarters in Littleton, Colorado, with additional sites in Valley Forge, Pennsylvania; Sunnyvale, California; Santa Cruz, California; Huntsville ...
,
MacDonald Dettwiler & Associates (MDA) and other aerospace companies.
It was the first NASA mission to Mars led by a public university.
''Phoenix'' was NASA's sixth successful landing on Mars, from seven attempts, and the first in Mars' polar region. The lander completed its mission in August 2008, and made a last brief communication with Earth on November 2 as available
solar power
Solar power is the conversion of energy from sunlight into electricity, either directly using photovoltaics (PV) or indirectly using concentrated solar power. Photovoltaic cells convert light into an electric current using the photovoltaic e ...
dropped with the Martian winter. The mission was declared concluded on November 10, 2008, after engineers were unable to re-contact the craft.
After unsuccessful attempts to contact the lander by the ''
Mars Odyssey
''2001 Mars Odyssey'' is a robotic spacecraft orbiting the planet Mars. The project was developed by NASA, and contracted out to Lockheed Martin, with an expected cost for the entire mission of US$297 million. Its mission is to use spectro ...
'' orbiter up to and past the Martian summer solstice on May 12, 2010, JPL declared the lander to be dead. The program was considered a success because it completed all planned science experiments and observations.
Mission overview
![070802 phoenix lab 02](https://upload.wikimedia.org/wikipedia/commons/f/f6/070802_phoenix_lab_02.jpg)
The mission had two goals. One was to study the
geological
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Eart ...
history of water, the key to unlocking the story of past
climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
. The second was to evaluate past or potential
planetary habitability
Planetary habitability is the measure of a planet's or a natural satellite's potential to develop and maintain environments hospitable to life. Life may be generated directly on a planet or satellite endogenously or be transferred to it from ...
in the ice-soil boundary. ''Phoenixs instruments were suitable for uncovering information on the geological and possibly biological history of the Martian Arctic. ''Phoenix'' was the first mission to return data from either of the poles, and contributed to NASA's main strategy for Mars exploration, "''Follow the water.''"
The primary mission was anticipated to last 90
sols (Martian days)—just over 92 Earth days. However, the craft exceeded its expected operational lifetime
by a little over two months before succumbing to the increasing cold and dark of an advancing Martian winter.
Researchers had hoped that the lander would survive into the Martian winter so that it could witness polar ice developing around it – perhaps up to of solid carbon dioxide ice could have appeared. Even had it survived some of the winter, the intense cold would have prevented it from lasting all the way through. The mission was chosen to be a fixed lander rather than a rover because:
* costs were reduced through reuse of earlier equipment (though this claim is disputed by some observers
);
* the area of Mars where ''Phoenix'' landed is thought to be relatively uniform, thus traveling on the surface is of less value; and
* the
weight budget needed for mobility could instead be used for more and better scientific instruments.
The 2003–2004 observations of
methane gas on Mars were made remotely by three teams working with separate data. If the methane is truly present in the
atmosphere of Mars
The atmosphere of Mars is the layer of gases surrounding Mars. It is primarily composed of carbon dioxide (95%), molecular nitrogen (2.8%), and argon (2%). It also contains trace levels of water vapor, oxygen, carbon monoxide, hydrogen, and no ...
, then something must be producing it on the planet now, because the gas is broken down by radiation on Mars within 300 years;
[Mumma, M. J.; Novak, R. E.; DiSanti, M. A.; Bonev, B. P.]
"A Sensitive Search for Methane on Mars"
(abstract only). American Astronomical Society, DPS meeting #35, #14.18. therefore, it was considered important to determine the biological potential or
habitability
Habitability refers to the adequacy of an environment for human living. Where housing is concerned, there are generally local ordinances which define habitability. If a residence complies with those laws it is said to be habitable. In extreme e ...
of the Martian arctic's soils. Methane could also be the product of a
geochemical
Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the e ...
process or the result of
volcanic
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most often found where tectonic plates a ...
or
hydrothermal activity
Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...
.
History
![Phoenix Mars Lander in testing PIA01885](https://upload.wikimedia.org/wikipedia/commons/7/79/Phoenix_Mars_Lander_in_testing_PIA01885.jpg)
While the proposal for ''Phoenix'' was being written, the
''Mars Odyssey'' orbiter used its
gamma-ray spectrometer
A gamma-ray spectrometer (GRS) is an instrument for measuring the distribution (or spectrum—see figure) of the intensity of gamma radiation versus the energy of each photon.
The study and analysis of gamma-ray spectra for scientific and technic ...
and found the distinctive signature of
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...
on some areas of the
Martian surface
The study of surface characteristics (or surface properties and processes) is a broad category of Mars science that examines the nature of the materials making up the Martian surface. The study evolved from telescopic and remote-sensing techniques ...
, and the only plausible source of hydrogen on Mars would be
water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
in the form of ice, frozen below the surface. The mission was therefore funded on the expectation that ''Phoenix'' would find water ice on the arctic plains of Mars. In August 2003 NASA selected the
University of Arizona
The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory.
T ...
"''Phoenix''" mission for launch in 2007. It was hoped this would be the first in a new line of smaller, low-cost,
Scout
Scout may refer to:
Youth movement
*Scout (Scouting), a child, usually 10–18 years of age, participating in the worldwide Scouting movement
**Scouts (The Scout Association), section for 10-14 year olds in the United Kingdom
**Scouts BSA, sectio ...
missions in the agency's
exploration of Mars
The planet Mars has been explored remotely by spacecraft. Probes sent from Earth, beginning in the late 20th century, have yielded a large increase in knowledge about the Martian system, focused primarily on understanding its geology and habit ...
program. The selection was the result of an intense two-year competition with proposals from other institutions. The $325 million NASA award is more than six times larger than any other single research grant in University of Arizona history.
Peter H. Smith
Peter Hopkinson Smith (born January 17, 1940) is a scholar of Latin American history, politics, economics, and diplomacy. He is a distinguished Professor Emeritus of Political Science and the Simon Bolivar Professor of Latin American Studies at ...
of the University of Arizona Lunar and Planetary Laboratory, as Principal Investigator, along with 24 Co-Investigators, were selected to lead the mission. The mission was named after the
Phoenix
Phoenix most often refers to:
* Phoenix (mythology), a legendary bird from ancient Greek folklore
* Phoenix, Arizona, a city in the United States
Phoenix may also refer to:
Mythology
Greek mythological figures
* Phoenix (son of Amyntor), a ...
, a mythological bird that is repeatedly reborn from its own ashes. The ''Phoenix'' spacecraft contains several previously built components. The lander used was the modified
Mars Surveyor 2001 Lander (canceled in 2000), along with several of the instruments from both that and the previous unsuccessful
Mars Polar Lander
The Mars Polar Lander, also known as the Mars Surveyor '98 Lander, was a 290-kilogram robotic spacecraft lander launched by NASA on January 3, 1999, to study the soil and climate of Planum Australe, a region near the south pole on Mars. It for ...
mission.
Lockheed Martin
The Lockheed Martin Corporation is an American aerospace, arms, defense, information security, and technology corporation with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It ...
, who built the lander, had kept the nearly complete lander in an environmentally controlled
clean room
A cleanroom or clean room is an engineered space, which maintains a very low concentration of airborne particulates. It is well isolated, well-controlled from contamination, and actively cleansed. Such rooms are commonly needed for scientif ...
from 2001 until the mission was funded by the NASA
Scout Program.
![Sojourner, MER, Phoenix lander, and Curiosity comparisons, in Metric units](https://upload.wikimedia.org/wikipedia/commons/8/87/Sojourner%2C_MER%2C_Phoenix_lander%2C_and_Curiosity_comparisons%2C_in_Metric_units.jpg)
''Phoenix'' was a partnership of universities, NASA centers, and the aerospace industry. The science instruments and operations were a
University of Arizona
The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory.
T ...
responsibility.
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
's Jet Propulsion Laboratory in
Pasadena, California
Pasadena ( ) is a city in Los Angeles County, California, northeast of downtown Los Angeles. It is the most populous city and the primary cultural center of the San Gabriel Valley. Old Pasadena is the city's original commercial district.
I ...
, managed the project and provided mission design and control.
Lockheed Martin Space Systems
Lockheed Martin Space is one of the four major business divisions of Lockheed Martin. It has its headquarters in Littleton, Colorado, with additional sites in Valley Forge, Pennsylvania; Sunnyvale, California; Santa Cruz, California; Huntsville ...
built and tested the spacecraft. The
Canadian Space Agency
The Canadian Space Agency (CSA; french: Agence spatiale canadienne, ASC) is the national space agency of Canada, established in 1990 by the ''Canadian Space Agency Act''.
The president is Lisa Campbell, who took the position on September 3, 2020 ...
provided a
meteorological station
A weather station is a facility, either on land or sea, with instruments and equipment for measuring atmospheric conditions to provide information for weather forecasts and to study the weather and climate. The measurements taken include tempera ...
, including an innovative
laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...
-based atmospheric sensor. The co-investigator institutions included
Malin Space Science Systems
Malin Space Science Systems (MSSS) is a San Diego, California-based private technology company that designs, develops, and operates instruments and technical equipment to fly on unmanned spacecraft. MSSS is headed by chief scientist and CEO Mich ...
(California),
Max Planck Institute for Solar System Research
The Max Planck Institute for Solar System Research (abbreviation: MPS; german: Max-Planck-Institut für Sonnensystemforschung) is a research institute in astronomy and astrophysics located in Göttingen, Germany, where it relocated in February 201 ...
(Germany),
NASA Ames Research Center
The Ames Research Center (ARC), also known as NASA Ames, is a major NASA research center at Moffett Federal Airfield in California's Silicon Valley. It was founded in 1939 as the second National Advisory Committee for Aeronautics (NACA) laborat ...
(California),
NASA Johnson Space Center
The Lyndon B. Johnson Space Center (JSC) is NASA's center for human spaceflight (originally named the Manned Spacecraft Center), where human spaceflight training, research, and flight control are conducted. It was renamed in honor of the late U ...
(Texas),
MacDonald, Dettwiler and Associates
MDA Ltd. is a Canadian space technology company headquartered in Brampton, Ontario, Canada, that provides geointelligence, robotics & space operations, and satellite systems.
History
MDA (formerly MacDonald, Dettwiler and Associates) was founde ...
(Canada),
Optech Incorporated (Canada),
SETI Institute
The SETI Institute is a not-for-profit research organization incorporated in 1984 whose mission is to explore, understand, and explain the origin and nature of life in the universe, and to use this knowledge to inspire and guide present and futu ...
,
Texas A&M University
Texas A&M University (Texas A&M, A&M, or TAMU) is a public, land-grant, research university in College Station, Texas. It was founded in 1876 and became the flagship institution of the Texas A&M University System in 1948. As of late 2021, T ...
,
Tufts University
Tufts University is a private research university on the border of Medford and Somerville, Massachusetts. It was founded in 1852 as Tufts College by Christian universalists who sought to provide a nonsectarian institution of higher learning. ...
,
University of Colorado
The University of Colorado (CU) is a system of public universities in Colorado. It consists of four institutions: University of Colorado Boulder, University of Colorado Colorado Springs, University of Colorado Denver, and the University of Co ...
,
University of Copenhagen
The University of Copenhagen ( da, Københavns Universitet, KU) is a prestigious public university, public research university in Copenhagen, Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in ...
(Denmark),
University of Michigan
, mottoeng = "Arts, Knowledge, Truth"
, former_names = Catholepistemiad, or University of Michigania (1817–1821)
, budget = $10.3 billion (2021)
, endowment = $17 billion (2021)As o ...
,
University of Neuchâtel
The University of Neuchâtel (UniNE) is a French-speaking university based in Neuchâtel, Switzerland. The university has four faculties (schools) and more than a dozen institutes, including arts and human sciences, natural sciences, law and eco ...
(Switzerland),
University of Texas at Dallas
The University of Texas at Dallas (UTD or UT Dallas) is a public research university in Richardson, Texas. It is one of the largest public universities in the Dallas area and the northernmost institution of the University of Texas system. It wa ...
,
University of Washington
The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington.
Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattle a ...
,
Washington University in St. Louis
Washington University in St. Louis (WashU or WUSTL) is a private research university with its main campus in St. Louis County, and Clayton, Missouri. Founded in 1853, the university is named after George Washington. Washington University is r ...
, and
York University
York University (french: Université York), also known as YorkU or simply YU, is a public university, public research university in Toronto, Ontario, Canada. It is Canada's fourth-largest university, and it has approximately 55,700 students, 7,0 ...
(Canada). Scientists from
Imperial College London
Imperial College London (legally Imperial College of Science, Technology and Medicine) is a public research university in London, United Kingdom. Its history began with Prince Albert, consort of Queen Victoria, who developed his vision for a cu ...
and the
University of Bristol
, mottoeng = earningpromotes one's innate power (from Horace, ''Ode 4.4'')
, established = 1595 – Merchant Venturers School1876 – University College, Bristol1909 – received royal charter
, type ...
provided hardware for the mission and were part of the team operating the microscope station.
On June 2, 2005, following a critical review of the project's planning progress and preliminary design, NASA approved the mission to proceed as planned. The purpose of the review was to confirm NASA's confidence in the mission.
Specifications
;Launched mass
: Includes Lander, Aeroshell (backshell and heatshield), parachutes, cruise stage.
[
;Lander Mass
:
;Lander Dimensions
:About long with the ]solar panels
A solar cell panel, solar electric panel, photo-voltaic (PV) module, PV panel or solar panel is an assembly of photovoltaic solar cells mounted in a (usually rectangular) frame, and a neatly organised collection of PV panels is called a phot ...
deployed. The science deck by itself is about in diameter. From the ground to the top of the MET mast, the lander measures about tall.
;Communications
:X-band
The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is rather indefinitely set at approxim ...
throughout the cruise phase of the mission and for its initial communication after separating from the third stage of the launch vehicle
A launch vehicle or carrier rocket is a rocket designed to carry a payload (spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pad, launch pads, supported by a missile launch contro ...
. UHF links, relayed through Mars orbiters during the entry, descent and landing phase and while operating on the surface of Mars. The UHF system on ''Phoenix'' is compatible with relay capabilities of NASA's Mars Odyssey, Mars Reconnaissance Orbiter
''Mars Reconnaissance Orbiter'' (MRO) is a spacecraft designed to study the geology and climate of Mars, provide reconnaissance of future landing sites, and relay data from surface missions back to Earth. It was launched on August 12, 2005, an ...
and with the European Space Agency's Mars Express
''Mars Express'' is a space exploration mission being conducted by the European Space Agency (ESA). The ''Mars Express'' mission is exploring the planet Mars, and is the first planetary mission attempted by the agency. "Express" originally ref ...
. The interconnections use the Proximity-1 Proximity-1 Space Link Protocol is a short haul delivery communications protocol designed to establish a two-way communications link between a lander and an orbiter, negotiate data rate and communications mode, and reliably deliver data during short ...
protocol.
;Power
:Power for the cruise phase is generated using two decagon
In geometry, a decagon (from the Greek δέκα ''déka'' and γωνία ''gonía,'' "ten angles") is a ten-sided polygon or 10-gon.. The total sum of the interior angles of a simple decagon is 1440°.
A self-intersecting ''regular decagon'' i ...
al gallium arsenide
Gallium arsenide (GaAs) is a III-V direct band gap semiconductor with a Zincblende (crystal structure), zinc blende crystal structure.
Gallium arsenide is used in the manufacture of devices such as microwave frequency integrated circuits, monoli ...
solar panels
A solar cell panel, solar electric panel, photo-voltaic (PV) module, PV panel or solar panel is an assembly of photovoltaic solar cells mounted in a (usually rectangular) frame, and a neatly organised collection of PV panels is called a phot ...
(total area ) mounted to the cruise stage, and for the lander, via two gallium arsenide solar array panels (total area ) deployed from the lander after touchdown on the Martian surface. NiH2 battery with a capacity of 16 A·h
An ampere hour or amp hour (symbol: A⋅h or A h; often simplified as Ah) is a Unit of measurement, unit of electric charge, having Dimensional analysis, dimensions of electric current multiplied by time, equal to the charge transferred by a ...
.
Lander systems include a RAD6000
The RAD6000 radiation-hardened single-board computer, based on the IBM RISC Single Chip CPU, was manufactured by IBM Federal Systems. IBM Federal Systems was sold to Loral, and by way of acquisition, ended up with Lockheed Martin and is ...
based computer system for commanding the spacecraft and handling data. Other parts of the lander are an electrical system containing solar arrays
A photovoltaic system, also PV system or solar power system, is an electric power system designed to supply usable solar power by means of photovoltaics. It consists of an arrangement of several components, including solar panels to absorb and c ...
and batteries, a guidance system to land the spacecraft, eight and monopropellant
Monopropellants are propellants consisting of chemicals that release energy through exothermic chemical decomposition. The molecular bond energy of the monopropellant is released usually through use of a catalyst. This can be contrasted with biprop ...
hydrazine
Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly toxic unless handled in solution as, for example, hydrazine ...
engines built by Aerojet
Aerojet was an American rocket and missile propulsion manufacturer based primarily in Rancho Cordova, California, with divisions in Redmond, Washington, Orange and Gainesville in Virginia, and Camden, Arkansas. Aerojet was owned by GenCorp. ...
-Redmond Operations for the cruise phase, twelve Aerojet monopropellant hydrazine thrusters to land the ''Phoenix'', mechanical and structural elements, and a heater system to ensure the spacecraft does not get too cold.
Scientific payload
''Phoenix'' carried improved versions of University of Arizona panoramic cameras and volatiles-analysis instrument from the ill-fated Mars Polar Lander
The Mars Polar Lander, also known as the Mars Surveyor '98 Lander, was a 290-kilogram robotic spacecraft lander launched by NASA on January 3, 1999, to study the soil and climate of Planum Australe, a region near the south pole on Mars. It for ...
, as well as experiments that had been built for the canceled Mars Surveyor 2001 Lander, including a JPL trench-digging robotic arm, a set of wet chemistry laboratories, and optical and atomic force microscope
Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very-high-resolution type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the diffr ...
s. The science payload also included a descent imager and a suite of meteorological instruments.
During EDL, the Atmospheric Structure Experiment was conducted. This used accelerometer and gyroscope data recorded during the lander's descent through the atmosphere to create a vertical profile of the temperature, pressure, and density of the atmosphere above the landing site, at that point in time.
Robotic arm and camera
The robotic arm was designed to extend from its base on the lander, and had the ability to dig down to below a sandy surface. It took samples of dirt and ice that were analyzed by other instruments on the lander. The arm was designed and built for the Jet Propulsion Laboratory by ''Alliance Spacesystems, LLC'' (now MDA US Systems, LLC) in Pasadena, California. A rotating rasp-tool located in the heel of the scoop was used to cut into the strong permafrost. Cuttings from the rasp were ejected into the heel of the scoop and transferred to the front for delivery to the instruments. The rasp tool was conceived of at the Jet Propulsion Laboratory. The flight version of the rasp was designed and built by HoneyBee Robotics. Commands were sent for the arm to be deployed on May 28, 2008, beginning with the pushing aside of a protective covering intended to serve as a redundant precaution against potential contamination of Martian soil by Earthly life-forms.
The Robotic Arm Camera (RAC) attached to the robotic arm just above the scoop was able to take full-color pictures of the area, as well as verify the samples that the scoop returned, and examined the grains of the area where the robotic arm had just dug. The camera was made by the University of Arizona
The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory.
T ...
and Max Planck Institute for Solar System Research
The Max Planck Institute for Solar System Research (abbreviation: MPS; german: Max-Planck-Institut für Sonnensystemforschung) is a research institute in astronomy and astrophysics located in Göttingen, Germany, where it relocated in February 201 ...
, Germany.
Surface stereo imager
The Surface Stereo Imager (SSI) was the primary camera on the lander. It is a stereo camera
A stereo camera is a type of camera with two or more lenses with a separate image sensor or film frame for each lens. This allows the camera to simulate human binocular vision, and therefore gives it the ability to capture three-dimensional i ...
that is described as "a higher resolution upgrade of the imager used for Mars Pathfinder
''Mars Pathfinder'' (''MESUR Pathfinder'') is an American robotic spacecraft that landed a base station with a roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight, wheeled robot ...
and the Mars Polar Lander
The Mars Polar Lander, also known as the Mars Surveyor '98 Lander, was a 290-kilogram robotic spacecraft lander launched by NASA on January 3, 1999, to study the soil and climate of Planum Australe, a region near the south pole on Mars. It for ...
". It took several stereo images of the Martian Arctic, and also used the Sun as a reference to measure the atmospheric distortion of the Martian atmosphere
The atmosphere of Mars is the layer of gases surrounding Mars. It is primarily composed of carbon dioxide (95%), molecular nitrogen (2.8%), and argon (2%). It also contains trace levels of water vapor, oxygen, carbon monoxide, hydrogen, and no ...
due to dust, air and other features. The camera was provided by the University of Arizona
The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory.
T ...
in collaboration with the Max Planck Institute for Solar System Research
The Max Planck Institute for Solar System Research (abbreviation: MPS; german: Max-Planck-Institut für Sonnensystemforschung) is a research institute in astronomy and astrophysics located in Göttingen, Germany, where it relocated in February 201 ...
.
Thermal and evolved gas analyzer
The Thermal and Evolved Gas Analyzer
The Thermal and Evolved Gas Analyzer (TEGA) is a scientific instrument aboard the ''Phoenix'' spacecraft, a Mars lander which landed and operated on the planet Mars in 2008. TEGA's design is based on experience gained from the failed Mars Polar ...
(TEGA) is a combination of a high-temperature furnace with a mass spectrometer
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a ''mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used ...
. It was used to bake samples of Martian dust and determine the composition of the resulting vapors. It has eight ovens, each about the size of a large ball-point pen, which were able to analyze one sample each, for a total of eight separate samples. Team members measured how much water vapor and carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
gas were given off, how much water ice the samples contained, and what minerals are present that may have formed during a wetter, warmer past climate. The instrument also measured organic volatiles, such as methane
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Eart ...
, down to 10 Parts per billion
In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they ...
. TEGA was built by the University of Arizona
The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory.
T ...
and University of Texas at Dallas
The University of Texas at Dallas (UTD or UT Dallas) is a public research university in Richardson, Texas. It is one of the largest public universities in the Dallas area and the northernmost institution of the University of Texas system. It wa ...
.
On May 29, 2008 (sol ), electrical tests indicated an intermittent short circuit in TEGA, resulting from a glitch in one of the two filaments responsible for ionizing volatiles. NASA worked around the problem by configuring the backup filament as the primary and vice versa.
In early June, first attempts to get soil into TEGA were unsuccessful as it seemed too "cloddy" for the screens.
On June 11 the first of the eight ovens was filled with a soil sample after several tries to get the soil sample through the screen of TEGA. On June 17, it was announced that no water was found in this sample; however, since it had been exposed to the atmosphere for several days prior to entering the oven, any initial water ice it might have contained could have been lost via sublimation.
Mars Descent Imager
The Mars Descent Imager (MARDI) was intended to take pictures of the landing site during the last three minutes of descent. As originally planned, it would have begun taking pictures after the aeroshell departed, about above the Martian soil.
Before launch, testing of the assembled spacecraft uncovered a potential data corruption problem with an interface card that was designed to route MARDI image data as well as data from various other parts of the spacecraft. The potential problem could occur if the interface card were to receive a MARDI picture during a critical phase of the spacecraft's final descent, at which point data from the spacecraft's Inertial Measurement Unit
An inertial measurement unit (IMU) is an electronic device that measures and reports a body's specific force, angular rate, and sometimes the orientation of the body, using a combination of accelerometers, gyroscopes, and sometimes magnetometer ...
could have been lost; this data was critical to controlling the descent and landing. This was judged to be an unacceptable risk, and it was decided to not use MARDI during the mission. As the flaw was discovered too late for repairs, the camera remained installed on ''Phoenix'' but it was not used to take pictures, nor was its built-in microphone used.
MARDI images had been intended to help pinpoint exactly where the lander landed, and possibly help find potential science targets. It was also to be used to learn if the area where the lander lands is typical of the surrounding terrain. MARDI was built by Malin Space Science Systems
Malin Space Science Systems (MSSS) is a San Diego, California-based private technology company that designs, develops, and operates instruments and technical equipment to fly on unmanned spacecraft. MSSS is headed by chief scientist and CEO Mich ...
. It would have used only 3 watt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Wa ...
s of power during the imaging process, less than most other space cameras. It had originally been designed and built to perform the same function on the Mars Surveyor 2001 Lander mission; after that mission was canceled, MARDI spent several years in storage until it was deployed on the ''Phoenix'' lander.
Microscopy, electrochemistry, and conductivity analyzer
The Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) is an instrument package originally designed for the canceled Mars Surveyor 2001 Lander mission. It consists of a wet chemistry
Wet chemistry is a form of analytical chemistry that uses classical methods such as observation to analyze materials. It is called wet chemistry since most analyzing is done in the liquid phase. Wet chemistry is also called bench chemistry since ...
lab (WCL), optical
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...
and atomic force microscope
Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very-high-resolution type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the diffr ...
s, and a thermal and electrical conductivity
Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allow ...
probe. The Jet Propulsion Laboratory built MECA. A Swiss consortium led by the University of Neuchatel contributed the atomic force microscope.
Using MECA, researchers examined soil particles as small as 16 μm across; additionally, they attempted to determine the chemical composition of water-soluble ions in the soil. They also measured electrical and thermal conductivity of soil particles using a probe on the robotic arm scoop.
Sample wheel and translation stage
This instrument presents 6 of 69 sample holders to an opening in the MECA instrument to which the robotic arm delivers the samples and then brings the samples to the optical microscope and the atomic force microscope. Imperial College London
Imperial College London (legally Imperial College of Science, Technology and Medicine) is a public research university in London, United Kingdom. Its history began with Prince Albert, consort of Queen Victoria, who developed his vision for a cu ...
provided the microscope sample substrates.
Optical microscope
The optical microscope
The optical microscope, also referred to as a light microscope, is a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects. Optical microscopes are the oldest design of microsco ...
, designed by the University of Arizona
The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory.
T ...
, is capable of making images of the Martian regolith
Regolith () is a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock. It includes dust, broken rocks, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestria ...
with a resolution of 256 pixels/mm or 16 micrometers/pixel. The field of view of the microscope is a sample holder to which the robotic arm delivers the sample. The sample is illuminated either by 9 red, green and blue LED
A light-emitting diode (LED) is a semiconductor Electronics, device that Light#Light sources, emits light when Electric current, current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy i ...
s or by 3 LEDs emitting ultraviolet light
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
. The electronics for the readout of the CCD chip are shared with the robotic arm camera which has an identical CCD chip.
Atomic force microscope
The atomic force microscope
Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very-high-resolution type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the diffr ...
has access to a small area of the sample delivered to the optical microscope. The instrument scans over the sample with one of 8 silicon
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic tab ...
crystal tips and measures the repulsion of the tip from the sample. The maximum resolution is 0.1 micrometre
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...
s. A Swiss consortium led by the University of Neuchatel contributed the atomic force microscope.
Wet Chemistry Laboratory (WCL)
The wet chemistry lab (WCL) sensor assembly and leaching solution were designed and built by Thermo Fisher Scientific
Thermo Fisher Scientific Inc. is an American supplier of scientific instrumentation, reagents and consumables, and software services. Based in Waltham, Massachusetts, Thermo Fisher was formed through the merger of Thermo Electron and Fisher S ...
. The WCL actuator assembly was designed and built by Starsys Research in Boulder, Colorado. Tufts University
Tufts University is a private research university on the border of Medford and Somerville, Massachusetts. It was founded in 1852 as Tufts College by Christian universalists who sought to provide a nonsectarian institution of higher learning. ...
developed the reagent pellets, barium ISE, and ASV electrodes, and performed the preflight characterization of the sensor array.
The robotic arm scooped up some soil and put it in one of four wet chemistry lab cells, where water was added, and, while stirring, an array of electrochemical sensors measured a dozen dissolved ions such as sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable iso ...
, magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
, calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
, and sulfate
The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ar ...
that leached out from the soil into the water. This provided information on the biological compatibility of the soil, both for possible indigenous microbes and for possible future Earth visitors.
All of the four wet chemistry labs were identical, each containing 26 chemical sensors and a temperature sensor. The polymer Ion Selective Electrodes (ISE) were able to determine the concentration of ions by measuring the change in electric potential across their ion-selective membranes as a function of concentration. Two gas sensing electrodes for oxygen and carbon dioxide worked on the same principle but with gas-permeable membranes. A gold micro-electrode array was used for the cyclic voltammetry
Cyclic voltammetry (CV) is a type of potentiodynamic electrochemical measurement. In a cyclic voltammetry experiment, the working electrode potential is ramped linearly versus time. Unlike in linear sweep voltammetry, after the set potential is re ...
and anodic stripping voltammetry
Electrochemical stripping analysis is a set of analytical chemistry methods based on voltammetry or potentiometry that are used for quantitative determination of ions in solution. Stripping voltammetry (anodic, cathodic and adsorptive) have been e ...
. Cyclic voltammetry is a method to study ions by applying a waveform of varying potential and measuring the current–voltage curve. Anodic stripping voltammetry first deposits the metal ions onto the gold electrode with an applied potential. After the potential is reversed, the current is measured while the metals are stripped off the electrode.
Thermal and Electrical Conductivity Probe (TECP)
The MECA contains a Thermal and Electrical Conductivity Probe (TECP). The TECP, designed by Decagon Devices, has four probes that made the following measurements: Martian soil
Martian soil is the fine regolith (a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock) found on the surface of Mars. Its properties can differ significantly from those of terrestrial soil, including its to ...
temperature, relative humidity, thermal conductivity
The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by k, \lambda, or \kappa.
Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal ...
, electrical conductivity
Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allow ...
, dielectric permittivity
In electromagnetism, the absolute permittivity, often simply called permittivity and denoted by the Greek letter ''ε'' ( epsilon), is a measure of the electric polarizability of a dielectric. A material with high permittivity polarizes more in ...
, wind speed, and atmospheric temperature.
Three of the four probes have tiny heating elements and temperature sensors inside them. One probe uses internal heating elements to send out a pulse of heat, recording the time the pulse is sent and monitoring the rate at which the heat is dissipated away from the probe. Adjacent needles sense when the heat pulse arrives. The speed that the heat travels away from the probe as well as the speed that it travels between probes allows scientists to measure thermal conductivity, specific heat (the ability of the regolith to conduct heat relative to its ability to store heat) and thermal diffusivity (the speed at which a thermal disturbance is propagated in the soil).
The probes also measured the dielectric permittivity
In electromagnetism, the absolute permittivity, often simply called permittivity and denoted by the Greek letter ''ε'' ( epsilon), is a measure of the electric polarizability of a dielectric. A material with high permittivity polarizes more in ...
and electrical conductivity
Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allow ...
, which can be used to calculate moisture and salinity of the regolith
Regolith () is a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock. It includes dust, broken rocks, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestria ...
. Needles 1 and 2 work in conjunction to measure salts in the regolith, heat the soil to measure thermal properties (thermal conductivity, specific heat and thermal diffusivity) of the regolith, and measure soil temperature. Needles 3 and 4 measure liquid water in the regolith. Needle 4 is a reference thermometer for needles 1 and 2.
The TECP humidity sensor is a relative humidity sensor, so it must be coupled with a temperature sensor in order to measure absolute humidity. Both the relative humidity sensor and a temperature sensor are attached directly to the circuit board of the TECP and are, therefore, assumed to be at the same temperature.
Meteorological station
The Meteorological Station (MET) recorded the daily weather of Mars during the course of the ''Phoenix'' mission. It is equipped with a wind indicator and pressure and temperature sensors. The MET also contains a lidar
Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be ...
(light detection and ranging) device for sampling the number of dust particles in the air. It was designed in Canada by Optech and MDA
MDA, mda, or ''variation'', may refer to:
Places
* Moldova, a country in Europe with the ISO 3166-1 country code MDA Politics
* Meghalaya Democratic Alliance (2018), ruling coalition government in the Indian State of Meghalaya led by National Pe ...
, supported by the Canadian Space Agency. A team initially led by York University
York University (french: Université York), also known as YorkU or simply YU, is a public university, public research university in Toronto, Ontario, Canada. It is Canada's fourth-largest university, and it has approximately 55,700 students, 7,0 ...
's Professor Diane Michelangeli until her death in 2007, when Professor James Whiteway took over, oversaw the science operations of the station. The York University team includes contributions from the University of Alberta
The University of Alberta, also known as U of A or UAlberta, is a public research university located in Edmonton, Alberta, Canada. It was founded in 1908 by Alexander Cameron Rutherford,"A Gentleman of Strathcona – Alexander Cameron Rutherfor ...
, University of Aarhus
Aarhus University ( da, Aarhus Universitet, abbreviated AU) is a public research university with its main campus located in Aarhus, Denmark. It is the second largest and second oldest university in Denmark. The university is part of the Coimbra Gr ...
(Denmark), Dalhousie University
Dalhousie University (commonly known as Dal) is a large public research university in Nova Scotia
Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the fou ...
, Finnish Meteorological Institute
The Finnish Meteorological Institute (FMI; fi, Ilmatieteen laitos; sv, Meteorologiska institutet) is the government agency responsible for gathering and reporting weather data and forecasts in Finland. It is a part of the Ministry of Transport ...
, Optech, and the Geological Survey of Canada
The Geological Survey of Canada (GSC; french: Commission géologique du Canada (CGC)) is a Canadian federal government agency responsible for performing geological surveys of the country, developing Canada's natural resources and protecting the en ...
. Canadarm
Canadarm or Canadarm1 (officially Shuttle Remote Manipulator System or SRMS, also SSRMS) is a series of robotic arms that were used on the Space Shuttle orbiters to deploy, manoeuvre, and capture payloads. After the Space Shuttle ''Columbia' ...
maker MacDonald Dettwiler and Associates (MDA) of Richmond, B.C. built the MET.
The surface wind velocity, pressure, and temperature were also monitored over the mission (from the tell-tale, pressure, and temperature sensors) and show the evolution of the atmosphere with time. To measure dust and ice contribution to the atmosphere, a lidar was employed. The lidar collected information about the time-dependent structure of the planetary boundary layer
In meteorology, the planetary boundary layer (PBL), also known as the atmospheric boundary layer (ABL) or peplosphere, is the lowest part of the atmosphere and its behaviour is directly influenced by its contact with a planetary surface. On Ear ...
by investigating the vertical distribution of dust, ice, fog, and clouds in the local atmosphere.
There are three temperature sensors (thermocouple
A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of the ...
s) on a vertical mast (shown in its stowed position) at heights of approximately above the lander deck. The sensors were referenced to a measurement of absolute temperature at the base of the mast. A pressure sensor built by Finnish Meteorological Institute is located in the Payload Electronics Box, which sits on the surface of the deck, and houses the acquisition electronics for the MET payload. The Pressure and Temperature sensors commenced operations on Sol 0 (May 26, 2008) and operated continuously, sampling once every 2 seconds.
The Telltale is a joint Canadian/Danish instrument (right) which provides a coarse estimate of wind speed and direction. The speed is based on the amount of deflection from vertical that is observed, while the wind direction is provided by which way this deflection occurs. A mirror, located under the telltale, and a calibration "cross," above (as observed through the mirror) are employed to increase the accuracy of the measurement. Either camera, SSI or RAC, could make this measurement, though the former was typically used. Periodic observations both day and night aid in understanding the diurnal variability of wind at the ''Phoenix'' landing site.
The wind speeds ranged from . The usual average speed was .
The vertical-pointing lidar was capable of detecting multiple types of backscattering
In physics, backscatter (or backscattering) is the reflection of waves, particles, or signals back to the direction from which they came. It is usually a diffuse reflection due to scattering, as opposed to specular reflection as from a mirror, a ...
(for example Rayleigh scattering
Rayleigh scattering ( ), named after the 19th-century British physicist Lord Rayleigh (John William Strutt), is the predominantly elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the ...
and Mie Scattering
The Mie solution to Maxwell's equations (also known as the Lorenz–Mie solution, the Lorenz–Mie–Debye solution or Mie scattering) describes the scattering of an electromagnetic plane wave by a homogeneous sphere. The solution takes the f ...
), with the delay between laser pulse generation and the return of light scattered by atmospheric particles determining the altitude at which scattering occurs. Additional information was obtained from backscattered light at different wavelengths (colors), and the ''Phoenix'' system transmitted both 532 nm and 1064 nm. Such wavelength dependence may make it possible to discriminate between ice and dust, and serve as an indicator of the effective particle size.
The ''Phoenix'' lidar's laser was a passive Q-switch
Q-switching, sometimes known as giant pulse formation or Q-spoiling, is a technique by which a laser can be made to produce a pulsed output beam. The technique allows the production of light pulses with extremely high (gigawatt) peak power, much hi ...
ed Nd:YAG laser with the dual wavelengths of 1064 nm and 532 nm. It operated at 100 Hz with a pulse width of 10 ns. The scattered light was received by two detectors (green and IR) and the green signal was collected in both analog and photon counting modes.
The lidar was operated for the first time at noon on Sol 3 (May 29, 2008), recording the first surface extraterrestrial atmospheric profile. This first profile indicated well-mixed dust in the first few kilometers of the atmosphere of Mars
The atmosphere of Mars is the layer of gases surrounding Mars. It is primarily composed of carbon dioxide (95%), molecular nitrogen (2.8%), and argon (2%). It also contains trace levels of water vapor, oxygen, carbon monoxide, hydrogen, and no ...
, where the planetary boundary layer was observed by a marked decrease in scattering signal. The contour plot (right) shows the amount of dust as a function of time and altitude, with warmer colors (red, orange) indicating more dust, and cooler colors (blue, green), indicating less dust. There is also an instrumentation effect of the laser warming up, causing the appearance of dust increasing with time. A layer at can be observed in the plot, which could be extra dust, or—less likely, given the time of sol this was acquired—a low altitude ice cloud.
The image on the left shows the lidar laser operating on the surface of Mars, as observed by the SSI looking straight up; the laser beam is the nearly-vertical line just right of center. Overhead dust can be seen both moving in the background, as well as passing through the laser beam in the form of bright sparkles. The fact that the beam appears to terminate is the result of the extremely small angle at which the SSI is observing the laser—it sees farther up along the beam's path than there is dust to reflect the light back down to it.
The laser device discovered snow falling from clouds; this was not known to occur before the mission. It was also determined that cirrus clouds formed in the area.
Mission highlights
Launch
''Phoenix'' was launched on August 4, 2007, at 5:26:34 a.m. EDT (09:26:34 UTC) on a Delta II
Delta II was an expendable launch system, originally designed and built by McDonnell Douglas. Delta II was part of the Delta rocket family and entered service in 1989. Delta II vehicles included the Delta 6000, and the two later Delta 7000 va ...
7925 launch vehicle from Pad 17-A of the Cape Canaveral Air Force Station
Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida.
Headquartered at the nearby Patrick Space Force Base, the statio ...
. The launch was nominal with no significant anomalies. The ''Phoenix'' lander was placed on a trajectory
A trajectory or flight path is the path that an object with mass in motion follows through space as a function of time. In classical mechanics, a trajectory is defined by Hamiltonian mechanics via canonical coordinates; hence, a complete traj ...
of such precision that its first trajectory course correction burn, performed on August 10, 2007, at 7:30 a.m. EDT (11:30 UTC), was only 18 m/s. The launch took place during a launch window
In the context of spaceflight, launch period is the collection of days and launch window is the time period on a given day during which a particular rocket must be launched in order to reach its intended target. If the rocket is not launched wit ...
extending from August 3, 2007, to August 24, 2007. Due to the small launch window, the rescheduled launch of the ''Dawn'' mission (originally planned for July 7) had to be launched after ''Phoenix'' in September. The Delta II rocket was chosen due to its successful launch history, which includes launches of the ''Spirit'' and ''Opportunity'' Mars Exploration Rover
NASA's Mars Exploration Rover (MER) mission was a robotic space mission involving two Mars rovers, ''Spirit (rover), Spirit'' and ''Opportunity (rover), Opportunity'', exploring the planet Mars. It began in 2003 with the launch of the two rover ...
s in 2003 and Mars Pathfinder
''Mars Pathfinder'' (''MESUR Pathfinder'') is an American robotic spacecraft that landed a base station with a roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight, wheeled robot ...
in 1996.
A noctilucent cloud
Noctilucent clouds, or night shining clouds, are tenuous cloud-like phenomena in the upper atmosphere of Earth. When viewed from space, they are called polar mesospheric clouds (PMCs), detectable as a diffuse scattering layer of water ice cryst ...
was created by the exhaust gas
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline (petrol), diesel fuel, fuel oil, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through an ...
from the Delta II 7925 rocket used to launch ''Phoenix''. The colors in the cloud formed from the prism-like effect of the ice particles present in the exhaust trail.
Cruise
Entry, descent, and landing
The Jet Propulsion Laboratory made adjustments to the orbits of its two active satellites around Mars, Mars Reconnaissance Orbiter
''Mars Reconnaissance Orbiter'' (MRO) is a spacecraft designed to study the geology and climate of Mars, provide reconnaissance of future landing sites, and relay data from surface missions back to Earth. It was launched on August 12, 2005, an ...
and Mars Odyssey, and the European Space Agency
, owners =
, headquarters = Paris, Île-de-France, France
, coordinates =
, spaceport = Guiana Space Centre
, seal = File:ESA emblem seal.png
, seal_size = 130px
, image = Views in the Main Control Room (1205 ...
similarly adjusted the orbit of its Mars Express
''Mars Express'' is a space exploration mission being conducted by the European Space Agency (ESA). The ''Mars Express'' mission is exploring the planet Mars, and is the first planetary mission attempted by the agency. "Express" originally ref ...
spacecraft to be in the right place on May 25, 2008, to observe ''Phoenix'' as it entered the atmosphere and then landed on the surface. This information helps designers to improve future landers. The projected landing area was an ellipse covering terrain which has been informally named " Green Valley" and contains the largest concentration of water ice outside the poles.
''Phoenix'' entered the Martian atmosphere at nearly , and within 7 minutes had decreased its speed to before touching down on the surface. Confirmation of atmospheric entry was received at 4:46 p.m. PDT (23:46 UTC). Radio signals received at 4:53:44 p.m. PDT confirmed that ''Phoenix'' had survived its difficult descent and landed 15 minutes earlier, thus completing a 680 million km (422 million miles) flight from Earth.
For unknown reasons, the parachute was deployed about 7 seconds later than expected, leading to a landing position some east, near the edge of the predicted 99% landing ellipse
A landing footprint, also called a landing ellipse, is the area of uncertainty of a spacecraft's landing zone on an astronomical body. After atmospheric entry, a non-powered spacecraft will land in an area depending upon entry angle, entry mass, ...
.
''Mars Reconnaissance Orbiter
''Mars Reconnaissance Orbiter'' (MRO) is a spacecraft designed to study the geology and climate of Mars, provide reconnaissance of future landing sites, and relay data from surface missions back to Earth. It was launched on August 12, 2005, an ...
's'' High Resolution Imaging Science Experiment (HiRISE) camera photographed ''Phoenix'' suspended from its parachute during its descent through the Martian atmosphere. This marked the first time ever one spacecraft photographed another in the act of landing on a planet (the Moon not being a planet, but a satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...
). The same camera also imaged ''Phoenix'' on the surface with enough resolution to distinguish the lander and its two solar cell arrays. Ground controllers used Doppler tracking data from ''Odyssey'' and ''Mars Reconnaissance Orbiter'' to determine the lander's precise location as .
''Phoenix'' landed in the Green Valley of Vastitas Borealis
(Latin 'northern waste') is the largest lowland region of Mars. It is in the northerly latitudes of the planet and encircles the northern polar region. Vastitas Borealis is often simply referred to as the northern plains, northern lowlands or ...
on May 25, 2008, in the late Martian northern hemisphere spring ( Ls=76.73), where the Sun shone on its solar panels the whole Martian day.[Solar elevation varies from 3.2 to 46.3 degrees on May 25, and from 3.9 to 47.0 degrees on June 25, and from 0 to 43 degrees on September 2, verified using NASA']
Mars24 Sunclock
/ref> By the Martian northern Summer solstice (June 25, 2008), the Sun appeared at its maximum elevation of 47.0 degrees. ''Phoenix'' experienced its first sunset at the start of September 2008.
The landing was made on a flat surface, with the lander reporting only 0.3 degrees of tilt. Just before landing, the craft used its thrusters to orient its solar panels along an east–west axis to maximize power generation. The lander waited 15 minutes before opening its solar panels, to allow dust to settle. The first images from the lander became available around 7:00 p.m. PDT (2008-05-26 02:00 UTC). The images show a surface strewn with pebbles and incised with small troughs into polygons about across and high, with the expected absence of large rocks and hills.
Like the 1970s era ''Viking
Vikings ; non, víkingr is the modern name given to seafaring people originally from Scandinavia (present-day Denmark, Norway and Sweden),
who from the late 8th to the late 11th centuries raided, pirated, traded and se ...
'' spacecraft, ''Phoenix'' used retrorocket
A retrorocket (short for ''retrograde rocket'') is a rocket engine providing thrust opposing the motion of a vehicle, thereby causing it to decelerate. They have mostly been used in spacecraft, with more limited use in short-runway aircraft land ...
s for its final descent. Experiments conducted by Nilton Renno, mission co-investigator from the University of Michigan, and his students have investigated how much surface dust would be kicked up on landing. Researchers at Tufts University, led by co-investigator Sam Kounaves, conducted additional in-depth experiments to identify the extent of the ammonia contamination from the hydrazine propellant and its possible effects on the chemistry experiments. In 2007, a report to the American Astronomical Society
The American Astronomical Society (AAS, sometimes spoken as "double-A-S") is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC. The primary objective of the AAS is to promote the adv ...
by Washington State University
Washington State University (Washington State, WSU, or informally Wazzu) is a public land-grant research university with its flagship, and oldest, campus in Pullman, Washington. Founded in 1890, WSU is also one of the oldest land-grant unive ...
professor Dirk Schulze-Makuch, suggested that Mars might harbor peroxide
In chemistry, peroxides are a group of compounds with the structure , where R = any element. The group in a peroxide is called the peroxide group or peroxo group. The nomenclature is somewhat variable.
The most common peroxide is hydrogen p ...
- based life forms which the ''Viking'' landers failed to detect because of the unexpected chemistry. The hypothesis was proposed long after any modifications to ''Phoenix'' could be made. One of the ''Phoenix'' mission investigators, NASA astrobiologist Chris McKay
Christopher McKay, also known as Chris Taylor (born November 11, 1973), is an American filmmaker. He is best known for directing and editing three seasons of ''Robot Chicken'' and two seasons of ''Moral Orel''. He made his feature directorial ...
, stated that the report "piqued his interest" and that ways to test the hypothesis with ''Phoenixs instruments would be sought.
Surface mission
Communications from the surface
The robotic arm
A robotic arm is a type of mechanical arm, usually programmable, with similar functions to a human arm; the arm may be the sum total of the mechanism or may be part of a more complex robot. The links of such a manipulator are connected by joints ...
's first movement was delayed by one day when, on May 27, 2008, commands from Earth were not relayed to the ''Phoenix'' lander on Mars. The commands went to NASA's Mars Reconnaissance Orbiter as planned, but the orbiter's Electra
Electra (; grc, Ήλέκτρα) is one of the most popular mythological characters in tragedies.Evans (1970), p. 79 She is the main character in two Greek tragedies, '' Electra'' by Sophocles and '' Electra'' by Euripides. She is also the centra ...
UHF radio system for relaying commands to ''Phoenix'' temporarily shut off. Without new commands, the lander instead carried out a set of backup activities. On May 27 the Mars Reconnaissance Orbiter relayed images and other information from those activities back to Earth.
The robotic arm was a critical part of the ''Phoenix'' Mars mission. On May 28, scientists leading the mission sent commands to unstow its robotic arm and take more images of its landing site. The images revealed that the spacecraft landed where it had access to digging down a polygon across the trough and digging into its center.
The lander's robotic arm touched soil on Mars for the first time on May 31, 2008 (sol ). It scooped dirt and started sampling the Martian soil for ice after days of testing its systems.
Presence of shallow subsurface water ice
The polygonal cracking at the landing zone had previously been observed from orbit, and is similar to patterns seen in permafrost
Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean. Most common in the Northern Hemisphere, around 15% of the Northern Hemisphere or 11% of the global surface ...
areas in polar and high altitude regions of Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
. ''Phoenix''s robotic arm camera took an image underneath the lander on sol 5 that shows patches of a smooth bright surface uncovered when thruster exhaust blew off overlying loose soil. It was later shown to be water ice.
On June 19, 2008 (sol ), NASA announced that dice
Dice (singular die or dice) are small, throwable objects with marked sides that can rest in multiple positions. They are used for generating random values, commonly as part of tabletop games, including dice games, board games, role-playing g ...
-sized clumps of bright material in the "Dodo-Goldilocks" trench dug by the robotic arm had vaporize
Vaporization (or vaporisation) of an element or compound is a phase transition from the liquid phase to vapor. There are two types of vaporization: evaporation and boiling. Evaporation is a surface phenomenon, whereas boiling is a bulk phenomeno ...
d over the course of four days, strongly implying that they were composed of water ice which sublimed following exposure. While dry ice
Dry ice is the solid form of carbon dioxide. It is commonly used for temporary refrigeration as CO2 does not have a liquid state at normal atmospheric pressure and sublimates directly from the solid state to the gas state. It is used primarily a ...
also sublimes, under the conditions present it would do so at a rate much faster than observed.[Bright Chunks at ''Phoenix'' Lander's Mars Site Must Have Been Ice]
– Official NASA press release (June 19, 2008)
On July 31, 2008 (sol ), NASA announced that ''Phoenix'' confirmed the presence of water ice on Mars, as predicted in 2002 by the Mars Odyssey
''2001 Mars Odyssey'' is a robotic spacecraft orbiting the planet Mars. The project was developed by NASA, and contracted out to Lockheed Martin, with an expected cost for the entire mission of US$297 million. Its mission is to use spectro ...
orbiter. During the initial heating cycle of a new sample, TEGA's mass spectrometer detected water vapor when the sample temperature reached 0 °C.
Liquid water cannot exist on the surface of Mars with its present low atmospheric pressure, except at the lowest elevations for short periods.
With ''Phoenix'' in good working order, NASA announced operational funding through September 30, 2008 (sol ). The science team worked to determine whether the water ice ever thaws enough to be available for life processes and if carbon-containing chemicals and other raw materials for life are present.
Additionally during 2008 and early 2009 a debate emerged within NASA over the presence of 'blobs' which appeared on photos of the vehicle's landing struts, which have been variously described as being either water droplets or 'clumps of frost'. Due to the lack of consensus within the ''Phoenix'' science project, the issue had not been raised in any NASA news conferences.[Chang, Kenneth (2009]
Blobs in Photos of Mars Lander Stir a Debate: Are They Water?
New York Times (online), March 16, 2009, retrieved April 4, 2009;
One scientist thought that the lander's thrusters splashed a pocket of brine
Brine is a high-concentration solution of salt (NaCl) in water (H2O). In diverse contexts, ''brine'' may refer to the salt solutions ranging from about 3.5% (a typical concentration of seawater, on the lower end of that of solutions used for br ...
from just below the Martian surface onto the landing strut during the vehicle's landing. The salts would then have absorbed water vapor from the air, which would have explained how they appeared to grow in size during the first 44 sols (Martian days) before slowly evaporating as Mars temperature dropped.
Image:PIA10775 First trenches dug by Phoenix.jpg, The first two trenches dug by ''Phoenix'' in Martian soil. The trench on the right, informally called "Baby Bear", is the source of th
first samples delivered
to the onboard TEGA and the optical microscope
The optical microscope, also referred to as a light microscope, is a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects. Optical microscopes are the oldest design of microsco ...
for analysis.
Image:Ice sublimating in the Dodo-Goldilocks trench.gif, Clumps of bright material in the enlarged "Dodo-Goldilocks" trench vanished over the course of four days, implying that they were composed of ice which sublimated following exposure.[
Image:Evaporating ice on Mars Phoenix lander image.jpg, Color versions of the photos showing ice sublimation, with the lower left corner of the trench enlarged in the insets in the upper right of the images.
]
Wet chemistry
On June 24, 2008 (sol ), NASA's scientists launched a series of scientific tests. The robotic arm scooped up more soil and delivered it to 3 different on-board analyzers: an oven that baked it and tested the emitted gases, a microscopic imager, and a wet chemistry
Wet chemistry is a form of analytical chemistry that uses classical methods such as observation to analyze materials. It is called wet chemistry since most analyzing is done in the liquid phase. Wet chemistry is also called bench chemistry since ...
laboratory (WCL). The lander's robotic arm scoop was positioned over the Wet Chemistry Lab delivery funnel on Sol 29 (the 29th Martian day after landing, i.e. June 24, 2008). The soil was transferred to the instrument on sol (June 25, 2008), and ''Phoenix'' performed the first wet chemistry tests. On Sol 31 (June 26, 2008) ''Phoenix'' returned the wet chemistry test results with information on the salts in the soil, and its acidity. The wet chemistry lab (WCL) was part of the suite of tools called the Microscopy, Electrochemistry and Conductivity Analyzer (MECA).
Image:Phoenix mission landing.jpg, ''Phoenix'' footpad image, taken over 15 minutes after landing to ensure any dust stirred up had settled.
Image:Phoenix Sol1 pic3.jpg, One of the first surface images from ''Phoenix''.
Image:PIA10741 Possible Ice Below Phoenix.jpg, View underneath lander towards south foot pad, showing patchy exposures of a bright surface, possibly ice.
A 360-degree panorama assembled from images taken on sols 1 and 3 after landing. The upper portion has been vertically stretched by a factor of 8 to bring out details. Visible near the horizon at full resolution are the backshell and parachute (a bright speck above the right edge of the left solar array
A photovoltaic system, also PV system or solar power system, is an electric power system designed to supply usable solar power by means of photovoltaics. It consists of an arrangement of several components, including solar panels to absorb and ...
, about distant) and the heat shield and its bounce mark (two end-to-end dark streaks above the center of the left solar array, about distant); on the horizon, left of the weather mast, is a crater.
End of the mission
The solar-powered lander operated two months longer than its three-month prime mission. The lander was designed to last 90 days, and had been running on bonus time since the successful end of its primary mission in August 2008. On October 28, 2008 (sol ), the lander went into safe mode due to power constraints based on the insufficient amount of sunlight reaching the lander, as expected at this time of year. It was decided then to shut down the four heaters that keep the equipment warm, and upon bringing the lander back from safe mode, commands were sent to turn off two of the heaters rather than only one as was originally planned for the first step. The heaters involved provide heat to the robotic arm, TEGA instrument and a pyrotechnic unit on the lander that were unused since landing, so these three instruments were also shut down.
On November 10, Phoenix Mission Control reported the loss of contact with the ''Phoenix'' lander; the last signal was received on November 2. The demise of the craft occurred as a result of a dust storm that reduced power generation even further. While the spacecraft's work ended, the analysis of data from the instruments was in its earliest stages.
Communication attempts 2010
Though it was not designed to survive the frigid Martian winter, the spacecraft's safe mode kept the option open to reestablish communications if the lander could recharge its batteries during the next Martian spring. However, its landing location is in an area that is usually part of the north polar ice cap during the Martian winter, and the lander was seen from orbit to be encased in dry ice
Dry ice is the solid form of carbon dioxide. It is commonly used for temporary refrigeration as CO2 does not have a liquid state at normal atmospheric pressure and sublimates directly from the solid state to the gas state. It is used primarily a ...
. It is estimated that, at its peak, the layer of CO2 ice in the lander's vicinity would total about 30 grams/cm2, which is enough to make a dense slab of dry ice at least thick. It was considered unlikely that the spacecraft could endure these conditions, as its fragile solar panels would likely break off under so much weight.
Scientists attempted to make contact with ''Phoenix'' starting January 18, 2010 (sol ), but were unsuccessful. Further attempts in February and April also failed to pick up any signal from the lander. Project manager Barry Goldstein announced on May 24, 2010, that the project was being formally ended. Images from the Mars Reconnaissance Orbiter
''Mars Reconnaissance Orbiter'' (MRO) is a spacecraft designed to study the geology and climate of Mars, provide reconnaissance of future landing sites, and relay data from surface missions back to Earth. It was launched on August 12, 2005, an ...
showed that its solar panels were apparently irretrievably damaged by freezing during the Martian winter.
Results of the mission
Landscape
Unlike some other places visited on Mars with landers (''Viking
Vikings ; non, víkingr is the modern name given to seafaring people originally from Scandinavia (present-day Denmark, Norway and Sweden),
who from the late 8th to the late 11th centuries raided, pirated, traded and se ...
'' and ''Pathfinder
Pathfinder may refer to:
Businesses
* Pathfinder Energy Services, a division of Smith International
* Pathfinder Press, a publisher of socialist literature
Computing and information science
* Path Finder, a Macintosh file browser
* Pathfinder ( ...
''), nearly all the rocks near ''Phoenix'' are small. For about as far as the camera can see, the land is flat, but shaped into polygons between in diameter and are bounded by troughs that are deep. These shapes are due to ice in the soil expanding and contracting due to major temperature changes. The microscope showed that the soil on top of the polygons is composed of flat particles (probably a type of clay) and rounded particles. Also, unlike other places visited on Mars, the site has no ripples or dunes. Ice is present a few inches below the surface in the middle of the polygons, and along its edges, the ice is at least deep. When the ice is exposed to the Martian atmosphere it slowly sublimates. Some dust devil
A dust devil is a strong, well-formed, and relatively short-lived whirlwind. Its size ranges from small (half a metre wide and a few metres tall) to large (more than 10 m wide and more than 1 km tall). The primary vertical motion is u ...
s were observed.
Weather
Snow was observed to fall from cirrus clouds. The clouds formed at a level in the atmosphere that was around , so the clouds would have to be composed of water-ice, rather than carbon dioxide-ice (dry ice) because, at the low pressure of the Martian atmosphere, the temperature for forming carbon dioxide ice is much lower—less than . It is now thought that water ice (snow) would have accumulated later in the year at this location. This represents a milestone in understanding Martian weather. Wind speeds ranged from . The usual average speed was . These speeds seem high, but the atmosphere of Mars is very thin—less than 1% of the Earth's—and so did not exert much force on the spacecraft. The highest temperature measured during the mission was , while the coldest was .
Climate cycles
Interpretation of the data transmitted from the craft was published in the journal ''Science''. As per the peer reviewed data the presence of water ice has been confirmed and that the site had a wetter and warmer climate in the recent past. Finding calcium carbonate in the Martian soil leads scientists to think that the site had been wet or damp in the geological past. During seasonal or longer period diurnal cycles water may have been present as thin films. The tilt or obliquity of Mars changes far more than the Earth; hence times of higher humidity are probable.
Surface chemistry
Chemistry results showed the surface soil to be moderately alkaline
In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a base (chemistry), basic, ionic compound, ionic salt (chemistry), salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as ...
, with a pH of 7.7 ±0.5. The overall level of salinity
Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...
is modest. TEGA analysis of its first soil sample indicated the presence of bound water and CO2 that were released during the final (highest-temperature, 1,000 °C) heating cycle.
The elements detected and measured in the samples are chloride, bicarbonate
In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula .
Bicarbonate serves a crucial biochemic ...
, magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
, sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable iso ...
, potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosphe ...
, calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
, and sulfate
The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ar ...
. Further data analysis indicated that the soil contains soluble sulfate (SO42-) at a minimum of 1.1% and provided a refined formulation of the soil.
Analysis of the ''Phoenix'' WCL also showed that the Ca(ClO4)2 in the soil has not interacted with liquid water of any form, perhaps for as long as 600 million years. If it had, the highly soluble Ca(ClO4)2 in contact with liquid water would have formed only CaSO4. This suggests a severely arid environment, with minimal or no liquid water interaction. The pH and salinity level were viewed as benign from the standpoint of biology.
;Perchlorate
On August 1, 2008, ''Aviation Week'' reported that "''The White House has been alerted by NASA about plans to make an announcement soon on major new ''Phoenix'' lander discoveries concerning the "potential for life" on Mars, scientists tell Aviation Week & Space Technology.''" This led to a subdued media speculation on whether some evidence of past or present life had been discovered. To quell the speculation, NASA released the preliminary findings stating that Mars soil contains perchlorate
A perchlorate is a chemical compound containing the perchlorate ion, . The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. Per ...
() and thus may not be as life-friendly as thought earlier. The presence of almost 0.5% perchlorate
A perchlorate is a chemical compound containing the perchlorate ion, . The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. Per ...
s in the soil was an unexpected finding with broad implications.
Laboratory research published in July 2017 demonstrated that when irradiated with a simulated Martian UV flux, perchlorates become bacteriocidal. Two other compounds of the Martian surface, iron oxide
Iron oxides are chemical compounds composed of iron and oxygen. Several iron oxides are recognized. All are black magnetic solids. Often they are non-stoichiometric. Oxyhydroxides are a related class of compounds, perhaps the best known of whic ...
s and hydrogen peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3% ...
, act in synergy with irradiated perchlorates to cause a 10.8-fold increase in cell death when compared to cells exposed to UV radiation after 60 seconds of exposure. It was also found that abraded silicates (quartz and basalt) lead to the formation of toxic reactive oxygen species
In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (). Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen.
The reduction of molecular oxygen () p ...
. The results leaves the question of the presence of organic compounds open-ended since heating the samples containing perchlorate would have broken down any organics present. However, in the cold subsurface of Mars, which provides substantial protection against UV radiation, halotolerant organisms might survive enhanced perchlorate concentrations by physiological adaptations similar to those observed in the yeast ''Debaryomyces hansenii
''Debaryomyces hansenii'' is a species of yeast in the family Saccharomycetaceae. Also known as ''Candida famata'', it accounts for up to 2% of invasive candidiasis cases.
Ecology
''Debaryomyces hansenii'' is an osmo-, halo- and xerotolerant ...
'' exposed in lab experiments to increasing NaClO4 concentrations.
Perchlorate
A perchlorate is a chemical compound containing the perchlorate ion, . The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. Per ...
(ClO4) is a strong oxidizer
An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ). In other words, an oxid ...
, so it has the potential of being used for rocket fuel and as a source of oxygen for future missions. Also, when mixed with water, perchlorate can greatly lower freezing point of water, in a manner similar to how salt is applied to roads to melt ice. So, perchlorate may be allowing small amounts of liquid water to form on the surface of Mars today. Gullies
A gully is a landform created by running water, mass movement, or commonly a combination of both eroding sharply into soil or other relatively erodible material, typically on a hillside or in river floodplains or terraces. Gullies resemble lar ...
, which are common in certain areas of Mars, may have formed from perchlorate melting ice and causing water to erode soil on steep slopes. Perchlorates have also been detected at the landing site of the ''Curiosity'' rover, nearer equatorial Mars, and in the martian meteorite EETA79001, suggesting a "global distribution of these salts". Only highly refractory and/or well-protected organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
s are likely to be preserved in the frozen subsurface. Therefore, the MOMA
Moma may refer to:
People
* Moma Clarke (1869–1958), British journalist
* Moma Marković (1912–1992), Serbian politician
* Momčilo Rajin (born 1954), Serbian art and music critic, theorist and historian, artist and publisher
Places
; Ang ...
instrument planned to fly on the 2022 ExoMars rover
''Rosalind Franklin'', previously known as the ExoMars rover, is a planned robotic Mars rover, part of the international ExoMars programme led by the European Space Agency and the Russian Roscosmos State Corporation. The mission was schedule ...
will employ a method that is unaffected by the presence of perchlorates to detect and measure sub-surface organics.[
]
Attached to the deck of the lander (next to the US flag) is a special DVD compiled by The Planetary Society
The Planetary Society is an American internationally-active non-governmental nonprofit organization. It is involved in research, public outreach, and political space advocacy
Space advocacy is supporting or advocating for a human use of out ...
. The disc contain
Visions of Mars
a multimedia collection of literature and art about the Red Planet. Works include the text of H.G. Wells' 1897 novel ''War of the Worlds
''The War of the Worlds'' is a science fiction novel by English author H. G. Wells, first serialised in 1897 by '' Pearson's Magazine'' in the UK and by ''Cosmopolitan'' magazine in the US. The novel's first appearance in hardcover was i ...
'' (and the 1938 radio broadcast by Orson Welles
George Orson Welles (May 6, 1915 – October 10, 1985) was an American actor, director, producer, and screenwriter, known for his innovative work in film, radio and theatre. He is considered to be among the greatest and most influential f ...
), Percival Lowell
Percival Lowell (; March 13, 1855 – November 12, 1916) was an American businessman, author, mathematician, and astronomer who fueled speculation that there were canals on Mars, and furthered theories of a ninth planet within the Solar System. ...
's 1908 book ''Mars as the Abode of Life'' with a map of his proposed canals
Proposal(s) or The Proposal may refer to:
* Proposal (business)
* Research proposal
* Proposal (marriage)
* Proposition, a proposal in logic and philosophy
Arts, entertainment, and media
* ''The Proposal'' (album)
Films
* ''The Proposal' ...
, Ray Bradbury
Ray Douglas Bradbury (; August 22, 1920June 5, 2012) was an American author and screenwriter. One of the most celebrated 20th-century American writers, he worked in a variety of modes, including fantasy, science fiction, horror, mystery, and r ...
's 1950 novel ''The Martian Chronicles
''The Martian Chronicles'' is a science fiction fix-up novel, published in 1950, by American writer Ray Bradbury that chronicles the exploration and settlement of Mars, the home of indigenous Martians, by Americans leaving a troubled Earth that ...
'', and Kim Stanley Robinson
Kim Stanley Robinson (born March 23, 1952) is an American writer of science fiction. He has published twenty-two novels and numerous short stories and is best known for his ''Mars'' trilogy. His work has been translated into 24 languages. Many ...
's 1993 novel ''Green Mars
The ''Mars'' trilogy is a series of science fiction novels by Kim Stanley Robinson that chronicles the settlement and terraforming of the planet Mars through the personal and detailed viewpoints of a wide variety of characters spanning almost tw ...
''. There are also messages directly addressed to future Martian visitors or settlers from, among others, Carl Sagan
Carl Edward Sagan (; ; November 9, 1934December 20, 1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on ext ...
and Arthur C. Clarke. In 2006, The Planetary Society collected a quarter of a million names submitted through the Internet and placed them on the disc, which claims, on the front, to be "the first library on Mars." This DVD is made of a special silica glass designed to withstand the Martian environment, lasting for hundreds (if not thousands) of years on the surface while it awaits retrieval by future explorers. This is similar in concept to the Voyager Golden Record
The Voyager Golden Records are two phonograph records that were included aboard both Voyager spacecraft launched in 1977. The records contain sounds and images selected to portray the diversity of life and culture on Earth, and are intended for ...
that was sent on the ''Voyager 1
''Voyager 1'' is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and interstellar space beyond the Sun's heliosphere. Launched 16 days after its twin ''Voyager 2'', ''Voya ...
'' and ''Voyager 2
''Voyager 2'' is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. As a part of the Voyager program, it was launched 16 days before its twin, ''Voyager 1'', on a ...
'' missions.
The text just below the center of the disk reads:
A previous CD version was supposed to have been sent with the Russian spacecraft ''Mars 94'', intended to land on Mars in Fall 1995.
References
External links
;LPL, LMSS, JPL and NASA links
''Phoenix'' mission lead home page
at JPL
''Phoenix'' Profile
b
NASA's Solar System Exploration
NASA's ''Phoenix'' Photojournal
NASA's Phoenix Analyst's Notebook
for accessing mission data and documents
most recent first
NASA TV broadcast of ''Phoenix'' landing
(YouTube copy of NASA broadcast from 8 minutes before until 2 minutes after touchdown)
Blogs of the scientists and engineers of the ''Phoenix'' team from launch through the end of the mission.
;Other links
Complete List of Works on the ''Phoenix'' DVD
Written Introduction to the ''Visions of Mars'' Project
''Phoenix'' Mission Details Video
may 2008-2
Includes animation of ''Phoenix'' descent and landing, plus KSC images of pre-flight processing and launch
Article and news footage on the ''Phoenix'' landing
Mars ''Phoenix'' Blog Page
* ttp://en.mars.bartal.org/?p=17 Color panorama of the landing site
''Phoenix'' EDL Reconstruction 1B
– 9 minute video simulation based on actual EDL data
''Phoenix'' Mars Lander wins 2009 John L. "Jack" Swigert, Jr., Award for Space Achievement
Chris McKay: Results of the Phoenix Mission to Mars and Analog Sites on Earth
{{DEFAULTSORT:Phoenix (Spacecraft)
Mars Scout Program
Missions to Mars
NASA space probes
Mare Boreum quadrangle
Space probes launched in 2007
Spacecraft launched by Delta II rockets
Solar-powered robots
Derelict landers (spacecraft)
Soft landings on Mars
Astrobiology space missions
Message artifacts
2008 on Mars