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Information about Ers 2

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A full-size model of ERS-2.


European Remote-Sensing satellite (ERS) was the European Space Agency's first Earth-observing satellite. It was launched on July 17, 1991 into a Sun synchronous polar orbit at a height of 782–785 km.

ERS-1 carried an array of earth-observation instruments that gathered information about the Earth (land, water, ice and atmosphere) using a variety of measurement principles. These included:
  • RA-1 (Radar Altimeter) is a single frequency nadir-pointing radar altimeter operating in the Ku band.
  • ATSR-1 (Along-Track Scanning Radiometer) is a 4 channel infrared radiometer and microwave sounder for measuring temperatures at the sea-surface and the top of clouds.
  • SAR (synthetic aperture radar) operating in C band can detect changes in surface heights with sub-millimeter precision.
  • Wind Scatterometer used to calculate information on wind speed and direction.
  • MWR is a Microwave Radiometer used in measuring atmospheric water, as well as providing a correction for the atmospheric water for the altimeter.
To accurately determine its orbit, the satellite included the PRARE (Precision Range and Range-Rate Equipment) and a Laser Retroreflector. The PRARE was non-operational since launch. The Retroreflector was used for calibrating the Radar Altimeter to within 10 cm.

ERS-1 had various mission phases using 3-day, 35-day and a 336-day repeat cycle. The 336-day mission (Geodetic Mission) allowed for accurate mapping of the Earth's bathymetry and geoid over the seas using the Radar Altimeter.

ERS-1 failed on March 10, 2000, far exceeding its expected lifespan.

Its successor, ERS-2, was launched on April 21, 1995. Largely identical to ERS-1, it added additional instruments and included improvements to existing instruments including: When ERS-2 was launched, ERS-1 shared the same orbital plane. This allowed a tandem mission, with ERS-2 passing the same point on the ground 1 day later than ERS-1. ERS-2 has a repeat cycle of 35 days.

ERS-2 has been operating without gyroscopes since February 2001, resulting in some degradation of the data provided by the instruments. The tape drive aboard failed on June 22, 2003, leaving the instruments operating only within visibility of a ground station. Since the tape drive failure additional ground stations have been brought online to increase the data gathering abilities of the satellite. The Wind Scatterometer and GOME were the only instruments of their kind until the launch of MetOp-A.

The successor to ERS-2 is Envisat containing improved versions of many of the instruments onboard ERS-2.

Enlarge picture
Side view of full-size ERS-2 model.

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satellite is an object which has been placed into orbit by human endeavor. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon.
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European Space Agency (ESA), established in 1974, is an inter-governmental organisation dedicated to the exploration of space, currently with 17 member states. Its headquarters are in Paris.
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Earth observation satellites are satellites specifically designed to observe Earth from orbit, similar to reconnaissance satellites but intended for non-military uses such as environmental monitoring, meteorology, map making etc.
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July 17 is the 1st day of the year (2nd in leap years) in the Gregorian calendar. There are 0 days remaining.

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sun-synchronous orbit (sometimes incorrectly called a heliosynchronous orbit) is a geocentric orbit which combines altitude and inclination in such a way that an object on that orbit passes over any given point of the Earth's surface at the same local solar time.
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A polar orbit is an orbit in which a satellite passes above or nearly above both poles of the planet (or other celestial body) it is orbiting on each revolution. It therefore has an inclination of (or very close to) 90 degrees to the equator.
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1 kilometre =
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A kilometre (American spelling: kilometer, symbol km
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nadir (from Arabic ﻧـدﻳﺭ nadeer نظير nathir, "opposite") is the astronomical term for the point in the sky directly below the observer, or more precisely, the point in the sky with an
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Radar is a system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain.
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altimeter is an active instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth underwater.
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The Ku band (pronounced "kay-yoo"; Kurtz-under band) is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 12 to 18 GHz
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Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. The name means "below red" (from the Latin infra, "below"), red being the color of visible light with the longest wavelength.
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A radiometer is a device used to measure the radiant flux or power in electromagnetic radiation. Although the term is perhaps most generally applied to a device which measures infrared radiation, it can also be applied to detectors operating any wavelength in the electromagnetic
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Microwaves are electromagnetic waves with wavelengths shorter than one meter and longer than one millimeter, or frequencies between 300 megahertz and 300 gigahertz.
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Synthetic aperture radar (SAR) is a form of radar in which sophisticated post-processing of radar data is used to produce a very narrow effective beam. It can only be used by moving instruments over relatively immobile targets, but it has seen wide applications in remote sensing
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WIND (SOLARWIND) was a NASA spacecraft launched on November 1, 1994. It was deployed to study radio and plasma that occur in solar wind, in the Earth's magnetosphere. The spacecraft's original mission was to orbit the Sun at the L1
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A radar scatterometer is designed to determine the normalized radar cross section (sigma-0) of the surface. Scatterometers operate by transmitting a pulse of microwave energy towards the Earth's surface and measuring the reflected energy.
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A Microwave Radiometer (MWR) is a radiometer that measures energy emitted at sub-millimetre-to-centimetre wavelengths (at frequencies of 1-1000 GHz) known as microwaves. Their primary application has been onboard spacecraft measuring atmospheric and terrestrial radiation and are
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laser is a mechanical device that produces coherent radiation. The term "laser" is an acronym: Light Amplification by Stimulated Emission of Radiation.
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retroreflector is a device that reflects a wave front back along a vector that is parallel to but opposite in direction from the angle of incidence. This is unlike a mirror, which does that only if the mirror is exactly perpendicular to the wave front.
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retroreflector is a device that reflects a wave front back along a vector that is parallel to but opposite in direction from the angle of incidence. This is unlike a mirror, which does that only if the mirror is exactly perpendicular to the wave front.
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Radar is a system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain.
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altimeter is an active instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth underwater.
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1 centimetre =
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Bathymetry is the underwater equivalent to altimetry. The name comes from Greek βαθυς, deep, and μετρον, measure.
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geoid is that equipotential surface which would coincide exactly with the mean ocean surface of the Earth, if the oceans were to be extended through the continents (such as with very narrow canals). According to C.F.
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