Encyclopedia Astronautica
ERS 1-2


European earth resources radar satellite. 2 launches, 1991.07.17 (ERS 1) to 1995.04.21 (ERS 2). The primary mission of Europe's ERS-1 and -2 was to perform remote sensing of the Earth's oceans, ice caps, and coastal regions.

The satellites provided systematic, repetitive global measurements of wind speed and direction, wave height, surface temperatures, surface altitude, cloud cover, and atmospheric water vapor levels.

Data from ERS-1 was shared with NASA under a reciprocal agreement for Seasat and Nimbus 7 data. Some land imaging was performed with the satellites' SAR experiment. The satellites were controlled from ESA's Darmstadt control centre, with a large number of other stations providing additional tracking coverage.

The spacecraft was 3-Axis stabilized, zero momentum bias with control to 0.11 deg (pitch/roll) and 0.21 deg (yaw). The single solar panel was 11.7 m x 2.4 m and supported peak payload power of 2600 W. Battery storage capacity was 2650 WHr. The SAR antenna was 10 m x 1 m. S-Band communications were via a 2 kbps uplink. The high-rate X-Band downlink provided 105 Mbps and 15 Mbps. On-board recorders stored 6.5 Gbits.

Payloads were:

  • AMI (Active Microwave Instrument) - included a SAR (Synthetic Aperture Radar), Wave Scatterometer, and Wind Scatterometer
  • Radar Altimeter (RA)
  • Scanning Radiometer and Sounder (ASTR-M)
  • Laser Reflector (LRR) - used for precise orbit determination and RA calibration
  • Precision Ranging Equipment (PRARE) - used for orbit determination.

ERS-2 carried the same suite of instruments as ERS-1 with the addition of the Global Ozone Measuring Equipment (GOME) which measured ozone distribution in the outer atmosphere.

Having given excellent service for nine years, over three times its planned lifetime, the ERS-1 mission was ended on 10 March 2000 by a failure in the on-board attitude control system. Since its launch on 17 July 1991, ESA's first sun-synchronous polar-orbiting mission, made 45 000 orbits, acquiring more than 1.5 million individual Synthetic Aperture Radar (SAR) scenes. ERS-1 SAR images, together with the data from other instruments on board, were delivered to a worldwide community of some 4000 users in science and applications. Surface winds derived from the scatterometer and altimeter were supplied to meteorological services worldwide since 1991. The duration of the mission also meant that scientists had already observed several El Nino phenomena through combined observations of surface currents, topography, temperatures and winds. The measurements of sea surface temperatures, critical to the understanding of climate change, made by the ERS-1 Along-Track Scanning Radiometer were the most accurate ever from space. All these critical measurements were continued and enhanced by the follow-on ERS-2 mission.

AKA: European Remote Sensing Satellite.
Gross mass: 2,450 kg (5,400 lb).
Height: 11.00 m (36.00 ft).
First Launch: 1991.07.17.
Last Launch: 1995.04.21.
Number: 2 .

More... - Chronology...


Associated Countries
See also
  • Ariane First successful European commercial launch vehicle, developed from L3S Europa launch vehicle replacement design. Development of the Ariane 1 was authorised in July 1973, took eight years, and cost 2 billion 1986 Euros. More...

Associated Launch Vehicles
  • Ariane French orbital launch vehicle. First successful European commercial launch vehicle, developed from L3S Europa launch vehicle replacement design. Development of the Ariane 1 was authorised in July 1973, took eight years, and cost 2 billion 1986 Euros. More...
  • Ariane 4 French orbital launch vehicle. The ultimate Ariane development. Compared with the Ariane 2/3, the Ariane 4 featured stretched first (61%) and third stages, a strengthened structure, new propulsion bay layouts, new avionics, and the Spelda dual-payload carrier. The basic 40 version used no strap-on motors, while the Ariane 42L, 44L, 42P, 44P, and 44LP versions used varous combinations of solid and liquid propellant strap-on motors). Development was authorised in January 1982, with the objective of increasing payload by 90%. Total development cost 476 million 1986 ECU's. More...
  • Ariane 40 French orbital launch vehicle. 3 stage core vehicle with original Ariane H10 upper stage. A fully fueled Ariane core cannot lift off the ground without strap-on liquid or solid motors. When Ariane 4 is launched in this configuration, the propellant tanks of the first and second stages are not completely filled. More...

Associated Manufacturers and Agencies
  • ESA European agency overseeing development of rockets and spacecraft. European Space Agency, Europe. More...
  • Dornier German manufacturer of rockets and spacecraft. DaimlerChrysler Aerospace - Dornier Satellitensysteme GmbH, Germany. More...

Bibliography
  • McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: here.
  • JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. Web Address when accessed: here.

Associated Launch Sites
  • Kourou After the agreement with newly independent Algeria for France to evacuate their launch sites in that country, a location near Biscarosse was selected for French missile testing. However since only launches westwards across the Bay of Biscay could be made from this site, it was unsuitable for France's Diamant orbital launch vehicle. After reviewing 14 potential sites, a location in the South American French colony of Guiana was selected. This would allow over-water launches to a tremendous range of possible orbital inclinations -- from -100.5 deg to 1.5 deg. Being near the equator, it would provide the maximum assist from the earth's rotation for launches into equatorial orbits. The decision was formalized in April 1964 and in July 1966 ELDO chose the site for future launches of the Europa II launch vehicle. More...

ERS 1-2 Chronology


1991 July 17 - . 01:46 GMT - . Launch Site: Kourou. Launch Complex: Kourou ELA2. LV Family: Ariane. Launch Vehicle: Ariane 40. LV Configuration: Ariane 40 V44.
  • ERS 1 - . Mass: 2,384 kg (5,255 lb). Nation: Europe. Agency: ESA. Class: Earth. Type: Earth resources radar satellite. Spacecraft: ERS 1-2. USAF Sat Cat: 21574 . COSPAR: 1991-050A. Apogee: 775 km (481 mi). Perigee: 774 km (480 mi). Inclination: 98.5000 deg. Period: 100.30 min. Microwave, IR imaging of oceans, ice and land; SAR. ERS-1 was an Earth exploration satellite, using active and passive sensors for oceanography etc. Frequency plan: 2048.85/2225 MHz (TTC), 7225.2960/8489 MHz (PRARE), 8040, 8140 MHz (data transmission). Launch time 0146:31 UT. Designator ESA/91/02.

1995 April 21 - . 01:44 GMT - . Launch Site: Kourou. Launch Complex: Kourou ELA2. LV Family: Ariane. Launch Vehicle: Ariane 40. LV Configuration: Ariane 40+ V72.
  • ERS 2 - . Mass: 2,516 kg (5,546 lb). Nation: Europe. Agency: ESA. Class: Earth. Type: Earth resources radar satellite. Spacecraft: ERS 1-2. USAF Sat Cat: 23560 . COSPAR: 1995-021A. Apogee: 785 km (487 mi). Perigee: 784 km (487 mi). Inclination: 98.6000 deg. Period: 100.50 min. Summary: European Remote Sensing; carried SAR; ocean, land, ice, and atmospheric observations..

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