Terra (EOS AM-1) is a multi-national,

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, succeedin ...

scientific research

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 radioiso ...

in a Sun-synchronous

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...

around the

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 sur ...

that takes simultaneous measurements of Earth's atmosphere, land, and water to understand how Earth is changing and to identify the consequences for life on Earth. It is the flagship of the

Earth Observing System The Earth Observing System (EOS) is a program of NASA comprising a series of artificial satellite missions and scientific instruments in Earth orbit designed for long-term global observations of the land surface, biosphere, atmosphere, and oceans ...

(EOS) and the first satellite of the system which was followed by Aqua (launched in 2002) and Aura (launched in 2004). Terra was launched in 1999. The name "Terra" comes from the

Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

word for Earth. A naming contest was held by NASA among U.S. high school students. The winning essay was submitted by Sasha Jones of

Brentwood, Missouri Brentwood is an inner-ring suburb of St. Louis, located in St. Louis County, Missouri, United States. The population was 8,233 at the 2020 census. Geography Brentwood is located at (38.619102, -90.348715). According to the United States Census ...

. The identifier "AM-1" refers to its orbit, passing over the equator in the morning.

Launch

The satellite was launched from

Vandenberg Air Force Base Vandenberg may refer to: * Vandenberg (surname), including a list of people with the name * USNS ''General Hoyt S. Vandenberg'' (T-AGM-10), transport ship in the United States Navy, sank as an artificial reef in Key West, Florida * Vandenberg Sp ...

on December 18th, 1999, aboard an

Atlas IIAS Atlas II was a member of the Atlas family of launch vehicles, which evolved from the successful Atlas missile program of the 1950s. The Atlas II was a direct evolution of the Atlas I, featuring longer first stage tanks, higher-performing engines ...

vehicle and began collecting data on February 24th, 2000. It was placed into a near-polar, sun-synchronous orbit at an altitude of , with a 10:30am descending node.

Mission

PIA22825-FireballOverBeringSeaFromSpace-TerraSatellite-20181218

Terra carries a payload of five remote sensors designed to monitor the state of Earth's

environment Environment most often refers to: __NOTOC__ * Natural environment, all living and non-living things occurring naturally * Biophysical environment, the physical and biological factors along with their chemical interactions that affect an organism or ...

and ongoing changes in its

climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologi ...

system: * ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) ASTER creates high-resolution images of clouds, ice, water and the land surface using 3 different sensor subsystems. They are the Shortwave Infrared (SWIR); Thermal Infrared (TIR); and Visible and Near Infrared (VNIR). They cover 14 multi-spectral bands from visible to the thermal infrared. The SWIR stopped working in 2008. ASTER was provided by Japan's Ministry of Economy, Trade, and Industry. * CERES (Clouds and the Earth's Radiant Energy System) *

MISR Misr or MISR may refer to: * Misr, the romanized Arabic name for Egypt * misr, singular of Arabic ''amsar'', which were early Arabic "garrison towns" * Misr (domain name), a top-level Internet domain name * Misr, a variant of the AKM assault rifle ...

(Multi-angle Imaging SpectroRadiometer) *

MODIS The Moderate Resolution Imaging Spectroradiometer (MODIS) is a satellite-based sensor used for earth and climate measurements. There are two MODIS sensors in Earth orbit: one on board the Terra ( EOS AM) satellite, launched by NASA in 19 ...

(Moderate-resolution Imaging Spectroradiometer) * MOPITT (Measurements of Pollution in the Troposphere) Data from the satellite helps scientists better understand the spread of pollution around the globe. Studies have used instruments on Terra to examine trends in global carbon monoxide and

aerosol An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols are fog or mist, dust, forest exudates, and geyser steam. Examples of anthropogen ...

pollution. The data collected by Terra will ultimately become a new, 15-year global data set. After launch, operators observed that high energy protons like those found over the

South Atlantic Anomaly The South Atlantic Anomaly (SAA) is an area where Earth's inner Van Allen radiation belt comes closest to Earth's surface, dipping down to an altitude of . This leads to an increased flux of energetic particles in this region and exposes orbiti ...

or the poles could induce single-event upsets that would cause the Motor Drive Assembly (MDA) Built-In Test Equipment (BITE) to turn off the MDA. These false shut-downs occur 12–14 times a month and eventually the operations team automated the recovery to reduce the impact of these shut-downs. Starting in 2007, increased thermal resistance in the SWIR cryocooler of the ASTER instrument caused the temperature to gradually increase. By 2008, despite frequent attempts to recycle the cryocooler the data began to significantly degrade and on January 12, 2009, ASTER managers declared the SWIR no longer functional due to anomalously high SWIR detector temperatures. Data gathered after April 2008 was declared not usable. On October 13, 2009, Terra suffered a single battery cell failure anomaly and a battery heater control anomaly likely the result of a Micrometeoroid or Orbital Debris (MMOD) strike. On February 27, 2020, the Terra flight operations team conducted Terra's last inclination adjust maneuver due to the satellite's limited remaining fuel. With no more such maneuvers, Terra's mean local time has begun to drift starting in April 2021 and with it, its data quality. In October 2022, Terra is expected to reach and exceed a 10:15 AM MLT crossing which is expected to lead operators to initiate a constellation exit to a lower orbit altitude (694 km). Decommissioning would occur around 2025-26 followed by an un-controlled reentry several years later.

Malicious cyber activities

In June and October 2008 the spacecraft was targeted by hackers who gained unauthorized access to its command and control systems, but did not issue any commands.

Gallery of images by Terra

File:Firstmodisimage.jpg, The first image taken by Terra. File:Arctic eclipse.jpg, The

Solar eclipse of August 1, 2008 A total solar eclipse occurred at the Moon's descending node of the orbit on August 1, 2008. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A t ...

, over Russia, Norway, and the

Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...

as seen from

's Terra satellite. File:Great Britain Snowy.jpg, The effects of the European winter storms of 2009–2010 on Great Britain, seen from Terra. File:Gulf of Mexico oil spill May 1 cropped.jpg, The

Deepwater Horizon oil spill The ''Deepwater Horizon'' oil spill (also referred to as the "BP oil spill") was an industrial disaster that began on 20 April 2010 off of the coast of the United States in the Gulf of Mexico on the BP-operated Macondo Prospect, considere ...

oil slick as seen from space by

's Terra satellite on May 1, 2010. File:Gulf Oil Spill Creeps Towards Mississippi Delta.jpg, The Deepwater Horizon oil slick just off the Louisiana coast on April 30, 2010, visible from space. File:Hurricane Karl 2010-09-16 1720Z.jpg,

Hurricane Karl Hurricane Karl was the most destructive tropical cyclone on record to strike the Mexican state of Veracruz. The eleventh tropical storm, sixth hurricane, and fifth and final major hurricane of the 2010 Atlantic hurricane season, Karl formed from ...

, the most destructive hurricane of the

2010 Atlantic Hurricane Season The 2010 Atlantic hurricane season was the first of three consecutive very active Atlantic hurricane seasons, each with 19 named storms. This above average activity included 12 hurricanes, equaling the number that formed in 1969. Only ...

, approaches Mexico on September 16. File:Satellite image of Sweden in March 2002.jpg, Satellite image of Sweden in March 2002. File:Ash distribution from Hunga Tonga over Australia.jpg, Satellite image of the Ash distribution over Australia from the 2022 Hunga Tonga–Hunga Ha'apai eruption. File:Animation of TERRA trajectory around Earth.gif, Animation of Terra's orbit around the Earth. Earth is not shown.

References

External links