1991 - 2000; 1995 - 2011

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.

ERS-1 Mission Parameters

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

ERS-1 Orbit Parameters

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 was still supplying valuable data, and this long-term availability makes it possible to generate lengthy time series, an important resource for climate studies.

ERS-2 Mission Parameters

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

ERS-2 Orbit Parameters

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

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