CryoSat mission overview
CryoSat-2 carries a sophisticated radar altimeter to meet two principal challenges.
The first is to acquire accurate measurements of the thickness of floating sea ice so that annual variations can be detected. The second is to survey the surface of ice sheets accurately enough to detect small changes.
CryoSat-2's radar altimeter is based on heritage from existing instruments, but with several major enhancements designed to improve measurements of icy surfaces. Because of its operations in SAR and Interferometric modes, the altimeter is called SIRAL (SAR Interferometric Radar Altimeter). CryoSat-2 is orbiting Earth at an unusually high inclination, reaching latitudes of 88° north and south.
CryoSat-2 will determine the thickness of floating sea ice by measuring the freeboard of ice floes; that is the height by which the ice extends above the water surface. This technique has been demonstrated with the ERS-1 radar altimeter, but this instrument, as with all conventional radar altimeters, is hampered by its relatively low spatial resolution of about 5 km. CryoSat-2 will achieve improved spatial resolution of 250 m in the along-track direction using the Synthetic Aperture technique.
The first returning energy in the radar echo comes from the part of the Earth's surface closest to the satellite. Over sea ice (and ocean) this point is directly below the satellite, but on sloping surfaces, such as those found around the edges of ice sheets, this nearest point can be anywhere. CryoSat-2 is able to pin down the location of the echo in the fore- and aft-direction by using its SAR capability, but to resolve left and right an additional feature is needed. Over these sloping surfaces CryoSat-2 operates in the SAR-Interferometry mode, which provides the key measurements of the angle of arrival and thus the pin-pointed source of the echo.
|CryoSat -2 overview|
|Launched||8 April 2010|
|Mission duration||Minimum 3 years|
|Orbit||LEO, non Sun-synchronous|
|- Altitude||717 km|
|- Inclination||92 deg|
|- Repeat cycles||369 days with 30 day sub-cycle|
|Payload||SIRAL (SAR/Interferometric Radar Altimeter)|
|Mass||720 kg (incl 37 kg fuel)|
|Dimensions||4.60 x 2.4 x 2.2 m|
|Launch provider||International Space Company Kosmotras|
|Launcher||Russian/Ukrainian Dnepr based on SS-18 intercontinental ballistic missile|
First CryoSat sea-ice map of the Arctic presented at Le Bourget air show
CryoSat validation campaign takes place in the Arctic
1 February 2011
CryoSat data open to all
CryoSat goes live
End of commissioning phase
First data released to selected scientists for calibration and validation
8 April 2010
CryoSat-2 launched on 8 April at 15:57 CEST
7 April 2010
Russian State Commission give go-ahead to launch on 8 April at 15:57 CEST
19 March 2010
New launch date of 8 April announced
19 February 2010
Announcement that launch date of 25 February is delayed
CryoSat shipped to Baikonur, Kazakhstan to begin launch campaign
February 2010 target launch date announced
Ground segment declared ready
Prime instrument SIRAL rebuilt
Critical Design Review passed
24 February 2006
ESA receives the green light from its Member States to build and launch a CryoSat recovery mission, CryoSat-2.
8 October 2005
First CryoSat mission lost due to an anomaly in the launch sequence.
Last update: 21 June 2011