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MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) is a low frequency, pulse-limited
On May 4, 2005, ''Mars Express'' deployed the first of its two 20-metre-long
''New Scientist'', May 9, 2005 however, exposing it to sunlight for a few minutes on May 10 fixed the glitch.Mars Express's kinky radar straightened out - space
''New Scientist'', May 12, 2005 The second 20 m boom was successfully deployed on June 14. Both 20 m booms were needed to create a 40 m dipole antenna for MARSIS to work; a less crucial 7-meter-long monopole antenna was deployed on June 17. The radar booms were originally scheduled to be deployed in April 2004, but this was delayed out of fear that the deployment could damage the spacecraft through a whiplash effect. Due to the delay it was decided to split the four-week commissioning phase in two parts, with two weeks running up to July 4 and another two weeks in December 2005. The deployment of the booms was a critical and highly complex task, requiring effective inter-agency cooperation between ESA, NASA, industry partners, and public Universities.
Mars Express radar ready to work
/ref> A 2012 paper by the MARSIS team measured a difference between the dielectric constant of the northern and southern high-latitude regions. This is evidence that the material that fills the northern basin is a lower-density material, which could be interpreted as evidence of an ancient northern ocean. Using MARSIS data, 22 Italian scientists reported in July 2018 the discovery of a
"Science results from the MARSIS and SHARAD subsurface sounding radars on Mars and their relevance to radar sounding of icy moons in the Jovian system"
EPSC2010-726, European Planetary Science Congress 2010, Vol. 5 (accessed Nov. 17 2014) *
ESA - MARSIS Finds Buried Basins in Chryse PlanitiaESA - Buried Basins in Northern Lowlandsburied basins and ice - eSA
{{Satellite and spacecraft instruments Spacecraft instruments Geophysical imaging Mars Express Space radars
MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) is a low frequency, pulse-limited radar
Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, we ...
sounder and altimeter
An altimeter or an altitude meter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth under water. The m ...
developed by the University of Rome La Sapienza and Alenia Spazio (today Thales Alenia Space Italy). The Italian MARSIS instrument, which is operated by the European Space Agency, is operational and orbits Mars as an instrument for the ESA'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 ...
'' exploration mission.
The MARSIS Principal Investigator is Giovanni Picardi from the University of Rome "La Sapienza", Italy. It features ground-penetrating radar
Ground-penetrating radar (GPR) is a Geophysics, geophysical method that uses radar pulses to Geophysical imaging, image the subsurface. It is a non-intrusive method of surveying the sub-surface to investigate underground utilities such as concrete, ...
capabilities, which uses synthetic aperture techniques and a secondary receiving antenna to isolate subsurface reflections. MARSIS identified buried basins on Mars. MARSIS was funded by ASI (Italy) and NASA (USA). The processor runs the real-time operating system
A real-time operating system (RTOS) is an operating system (OS) for real-time applications that processes data and events that have critically defined time constraints. An RTOS is distinct from a time-sharing operating system, such as Unix, which m ...
EONIC Virtuoso.
Deployment
On May 4, 2005, ''Mars Express'' deployed the first of its two 20-metre-long radar
Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, we ...
booms for the MARSIS experiment. At first the boom didn't lock fully into place;Glitch strikes Mars Express's radar boom - space''New Scientist'', May 9, 2005 however, exposing it to sunlight for a few minutes on May 10 fixed the glitch.Mars Express's kinky radar straightened out - space
''New Scientist'', May 12, 2005 The second 20 m boom was successfully deployed on June 14. Both 20 m booms were needed to create a 40 m dipole antenna for MARSIS to work; a less crucial 7-meter-long monopole antenna was deployed on June 17. The radar booms were originally scheduled to be deployed in April 2004, but this was delayed out of fear that the deployment could damage the spacecraft through a whiplash effect. Due to the delay it was decided to split the four-week commissioning phase in two parts, with two weeks running up to July 4 and another two weeks in December 2005. The deployment of the booms was a critical and highly complex task, requiring effective inter-agency cooperation between ESA, NASA, industry partners, and public Universities.
Science
MARSIS transmits a series of modulated chirps at frequencies between 1.8 and 5.0 MHz in subsurface sounding mode, with a 1 MHz bandwidth. It also emits chirps sweeping between 0.1 and 5.4 MHz when ionosphere sounding. Depending on the mode, the pulsewidth is 30, 91 or 250 μs, and the nominalPulse repetition frequency
The pulse repetition frequency (PRF) is the number of pulses of a repeating signal in a specific time unit. The term is used within a number of technical disciplines, notably radar.
In radar, a radio signal of a particular carrier frequency is tu ...
is 130 Hz. Transmitted power is either 1.5 or 5 W.
Nominal science observations began during July 2005.ESA PortalMars Express radar ready to work
/ref> A 2012 paper by the MARSIS team measured a difference between the dielectric constant of the northern and southern high-latitude regions. This is evidence that the material that fills the northern basin is a lower-density material, which could be interpreted as evidence of an ancient northern ocean. Using MARSIS data, 22 Italian scientists reported in July 2018 the discovery of a
subglacial lake
A subglacial lake is a lake that is found under a glacier, typically beneath an ice cap or ice sheet. Subglacial lakes form at the boundary between ice and the underlying bedrock, where gravitational pressure decreases the pressure melting point ...
on Mars
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 at ...
, below the southern polar ice cap, and extending horizontally about , the first known stable body 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 ...
.
See also
*LRS LRS may refer to:
Science and technology
* Lactated Ringer's solution, used for intravenous administration
* Learning Record Store, a data store system
* Linear recursive sequence, a recurrence relation used in mathematics
* Linear reference syst ...
, Lunar radar sounder (LRS) is a orbiting low frequency radar sounder and altimeter over Earth's Moon
*RIME
Rime may refer to:
*Rime ice, ice that forms when water droplets in fog freeze to the outer surfaces of objects, such as trees
Rime is also an alternative spelling of "rhyme" as a noun:
*Syllable rime, term used in the study of phonology in ling ...
, Radar for Icy Moons Exploration (RIME) is a orbiting low frequency radar sounder and altimeter for Jupiter's Icy moons
* SHARAD
Sharad/Sarath/Sharath ( sa, शरद्)is the autumn season or ritu in the Hindu calendar. It roughly corresponds to the western months of mid-September to mid-November. Sharad is preceded by Varsha and followed by Hemant. The Hindu calendar c ...
, The Mars SHAllow RADar sounder (SHARAD) radar (20 MHz) on the later launched Mars Reconnaissance Orbiter complements MARSIS capabilities.R. Orosei ''et al.,'"Science results from the MARSIS and SHARAD subsurface sounding radars on Mars and their relevance to radar sounding of icy moons in the Jovian system"
EPSC2010-726, European Planetary Science Congress 2010, Vol. 5 (accessed Nov. 17 2014) *
Tianwen-1
-1 (TW-1; zh, t=, s=, l='Heavenly Questions') is an interplanetary mission by the China National Space Administration (CNSA) which sent a robotic spacecraft to Mars, consisting of 6 spacecraft: an orbiter, two deployable cameras, lander, remo ...
, The Tianwen-1 mission plans an Orbiter Subsurface Radar (OSR) and rover based Ground-Penetrating Radar (GPR) for Mars
* WISDOM (radar), Water Ice and Subsurface Deposit Observation on Mars (WISDOM) is a ground-penetrating radar on the ExoMars rover
References
External links
ESA - MARSIS Finds Buried Basins in Chryse Planitia
{{Satellite and spacecraft instruments Spacecraft instruments Geophysical imaging Mars Express Space radars