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|  |  | ERS overview |  |  | | | |  | ERS-2 spacecraft and applications | | European Remote Sensing satellite, ERS-1, launched in 1991, was ESA's first Earth Observation satellite; it carried a comprehensive payload including an imaging Synthetic Aperture Radar (SAR), a radar altimeter and other powerful instruments to measure ocean surface temperature and winds at sea. ERS-2, which overlapped with ERS-1, was launched in 1995 with an additional sensor for atmospheric ozone research.
At their time of launch the two ERS satellites were the most sophisticated Earth observation spacecraft ever developed and launched in Europe. These highly successful ESA satellites have collected a wealth of valuable data on the Earth’s land surfaces, oceans, and polar caps and have been called upon to monitor natural disasters such as severe flooding or earthquakes in remote parts of the world.
Both ERS satellites were built with a core payload of two specialised radars and an infrared imaging sensor. The two spacecraft were designed as identical twins with one important difference – ERS-2 included an extra instrument designed to monitor ozone levels in the atmosphere.
Shortly after the launch of ERS-2 in 1995 ESA decided to link the two spacecraft in the first ever ‘tandem’ mission which lasted for nine months. During this time the increased frequency and level of data available to scientists offered a unique opportunity to observe changes over a very short space of time, as both satellites orbited Earth only 24 hours apart.
In March 2000 a computer and gyro control failure led to the ERS-1 satellite finally ending its operations, far exceeding its planned lifetime. ERS-2 is expected to continue operating for several more years. | | | ERS - 1 | ERS - 2 | | Launch | from Kourou, French Guiana | 17 July 1991 | 21 April 1995 | | Launcher | Ariane 4 | | | | Launch mass | | 2384 kg | 2516 kg | | Number of instruments | 4/5 including SAR with GOME added to ERS-2 | | | | Orbit | Sun synchronous, altitude 800 km | | | | Inclination | 98.5 degrees | | | | Time for one orbit | 100 minutes | | | | Cycle | 35 day repeat | | |
| Last update: 25 February 2008 | |
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