CryoSat

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CryoSat-1
CryoSat-1
Type: Research satellite
Operator: European space agencyESA ESA
Mission dates
Dimensions: 650 kg
Size: 4.60 m × 2.34 m × 2.20 m
Begin: October 8, 2005, 3:02 p.m. UTC
Starting place: Plesetsk Cosmodrome
Launcher: Rockot KM / Bris KM
Status: destroyed in case of false start
Orbit data

CryoSat (later referred to as CryoSat-1 because of the subsequent CryoSat-2 ) was a research satellite that was supposed to measure the cryosphere of the earth and in particular to record the volume of the ice masses in the Arctic and Antarctic . After the launch, however, the satellite did not reach its orbit due to a faulty control algorithm and crashed into the Arctic Ocean. CryoSat was the first of the Earth Explorer Missions within the Living Planet Program of the European Space Agency (ESA). From this mission science hoped to gain additional knowledge about changes in the earth's climate. The aim was to measure the exact surface heights of the ice sheets in Greenland and the Antarctic. In addition, the thickness of the floating sea ice should be recorded for the first time from space. A service life of at least three years was planned.

The total cost of the mission, including the launcher, operating costs and data analysis, was estimated by ESA at 136 million euros, of which 70 million euros for the satellite alone.

construction

The satellite, weighing 650 kg and measuring 4.60 × 2.34 × 2.20 meters, was built by EADS Astrium . Its main payload consisted of the SIRAL radar altimeter ( SAR / Interferometric Radar Altimeter) with two antennas measuring 1.14 × 1.25 meters, which operate with 25 watts of power at a frequency of 13.575 GHz. SIRAL should achieve a vertical resolution of 1 to 3 cm and a horizontal resolution of around 300 meters in its measurements. Radio signals should be sent with an interval of 50 µs and recorded again. Three different operating modes are provided for the different areas of application (land and sea ice): conventional pulse-limited operation, synthetic aperture mode and two-channel SAR / interferometric operation, with the SAR mode better distinguishing between ice and water and the interferometric operation allows a more accurate determination of the slope of the ice surface and its height. In addition, the radio receiver DORIS (Doppler Orbit and Radio Positioning Integration by Satellite) and a small was laser - retroreflector for exact positioning of the satellite on board. To communicate one was X-band - antenna for scientific data (on-board memory capacity of solid state recorder 256 Gbits) and an S-band - helical antenna for telemetry and control available. For navigation and attitude control, three Star Tracker cameras, magnetometers and magnetic field controls as well as cold gas attitude control engines , each with a thrust of 10 millinewtons, are used. The energy supply should be provided by gallium arsenide solar cells with 800 watts each and lithium ion batteries with 60 Ah that are firmly attached to the satellite surface. CryoSat was supposed to operate in a 720 km high polar orbit with an inclination of 92 °, optimized for the observation of the polar regions. The European Space Operations Center of ESA in Darmstadt should ensure the operation of the satellite.

Mission history

The satellite was carried out on 8 October 2005 at 15:02 UTC from Plesetsk cosmodrome from a Russian Rockot KM - launcher . After an initially perfect start, the Briz KM upper stage of the rocket did not separate from the second stage, so that the head part of the rocket together with the satellite fell in the Arctic Ocean ( Lincoln Sea between Greenland and the North Pole). The cause was a program error . The control provided for the second stage to be switched off after the third stage had ignited, while the third stage should only ignite after the second stopped firing. As a result, both stages remained coupled until the second stage burned out. The resulting course deviation led to the abortion of the launch and loss of the satellite.

CryoSat-2

After the failure, the member states of the ESA decided at the end of February 2006 to carry out a replacement mission because of the importance of the project. The originally intended start date for this was October 2009, due to various delays the start did not take place until April 8, 2010. The mission was initially designed for three years, but was extended to seven.

Web links

 Wikinews: ESA satellite "Cryosat" crashed at the North Pole  - news

Individual evidence

  1. ↑ ESA: The CryoSat System - The satellite and its radar altimeter by Guy Ratier, Richard Francis & Constantin Mavrocordatos (PDF; 497 kB)