ERS

In the 1990s, the European Space Agency ESA launched two ERS (Earth Remote Sensing) satellites.

In July 1991 ESA’s first earth observation mission was launched into space with ERS-1. Its payload consisted of five instruments: AMI (Active Microwave Instrument), which provided the functions of an imaging synthetic aperture radar (SAR) and a wind scatterometer; RA (Radar Altimeter); MWR (Microwave Radiometer); ATSR (Along Track Scanning Radiometer); and PRARE (Precise Range and Range-rate Equipment). The ERS-1 mission ended on March 10, 2000 after more than 45,000 orbits.

Dimensions
12 m × 12 m × 2.5 m
Total mass
2.16 t
Payload
888 kg
Number of instruments
5
Launcher
Ariane 4
Launch
July 1991
End of mission
March 10, 2000
Semi-major axis
7159 km
Orbit altitude (mean)
782 km
Inclination angle
98.5°
Orbital period
100 min
Orbit
polar, sun-synchronous
Overflight time
absteigender Knoten 10:30 Uhr vormittag
Orbits per day
14.3
Revisit
35 days (optionally 3 days or 168 days with slightly different orbit parameters)

The successor to ERS-1, the earth observation mission ERS-2 (Earth Remote Sensing Satellite 2), was launched in April 1995. For several years, both ERS satellites simultaneous monitored our home planet. ERS-2 has the same instrument suite as ERS-1 on board, with the addition of GOME (Global Ozone Monitoring Experiment) a sensor developed to study earth’s atmosphere. After 15 years in orbit, ERS-2 is still supplying valuable data, and this long-term availability makes it possible to generate lengthy time series, an important resource for climate studies.

Dimensions
11.8 m × 11.7 m × 2.4 m
Total mass
2.52 t
Payload
1.0 t
number of instruments
6
Launcher
Ariane 4
Launch
April 21, 1995
Semi-major axis
7147 km
Orbit altitude (mean)
785 km
Inclination angle
98.5°
Orbital period
100 min
Orbit
polar, sun-synchronous
Overflight time
descending node, 10:30 am
Orbits per day
14.3
Revisit
35 days

….. More on ERS at the ESA Website