Terra (satellite)

Terra
Type:	Earth observation satellite
Country:	United States
Operator:	NASA
COSPAR-ID :	1999-068A
Mission dates
Dimensions:	4864 kg
Begin:	December 18, 1999, 18:57 UTC
Starting place:	Vandenberg AFB , SLC-3E
Launcher:	Atlas IIAS
Status:	in orbit, active
Orbit data
Rotation time :	98 min
Orbit inclination :	98.8 °
Apogee height :	703 km
Perigee height :	701 km

Terra , also known as EOS-1 or EOS-AM1 , is an earth observation satellite launched on December 18, 1999 by the US aerospace agency NASA for the purpose of exploring and observing the earth . The planned lifespan of the satellite was originally 6 years.

Along with Aqua and Aura, Terra is one of the three main missions of the Earth Observing System (EOS), a long-term research program of NASA that includes several missions . The satellite cost about $ 1.3 billion.

Orbit data

SRTM -based 3D model of Mount Etna with ASTER-based false-color surface display

The satellite moves in a polar , sun-synchronous earth orbit (SSE).

A characteristic of this orbit is that the satellite passes one point on Earth at the same time every day. Therefore, such earth orbits are often used for meteorological satellites and earth observation satellites.

Instruments

The following five instruments are on board the satellite:

• ASTER ( Advanced Spaceborne Thermal Emission and Reflection Radiometer ) records high-resolution images on 14 channels from visible light (only red and green) to "thermal" infrared radiation . The resolution is 15 to 90 meters per pixel . From this, the height , surface temperature , reflectivity and emissivity of the recorded part of the earth's surface can be derived. The instrument was built in Japan .
• CERES ( Clouds and the Earth's Radiant Energy System ) determines the total heat flow from or to the earth and provides information about the nature of the clouds . There are two CERES instruments on board Terra, one of which is always observing straight towards the earth, while the other can be pivoted.
• MISR ( Multi-angle Imaging Spectro-Radiometer ) consists of 9 cameras , each with 4 color channels ( blue , green , red , near infrared ); the cameras observe the earth from different angles . The instrument examines the scattering of sunlight, clouds, aerosols and vegetation .
• MODIS ( MODerate-resolution Imaging Spectroradiometer ) has a relatively low resolution and works with 36 channels. It is used to detect large-scale changes in the biosphere .
• MOPITT ( Measurements of Pollution in the Troposphere ) measures the concentration of methane and carbon monoxide in the troposphere using gas correlation spectroscopy .

Terra began recording data on February 24, 2000.

Web links

Commons : Terra (satellite)  - collection of images, videos and audio files

• NASA's Terra project website
• Overview of Terra at NASA Science Directorate (archived 2008, English)
• Website of the Earth Observing System (English)
• Satellite Orbit on Heavens-Above (English)