CryoSat

CryoSat-2

The first will acquire accurate measurements of the thickness of floating sea ice so that annual variations can be detected. The second will 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 will orbit at an unusually high inclination, reaching latitudes of 88° North and South.  
 

	CryoSat measuring freeboard sea-ice

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.
 
 

CryoSat measuring ice sheet topographic surfaces.

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 will be 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 will operate 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   Launch 25 February 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)   DORIS receiver   Laser retroreflector   Star-trackers (3) 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

 
 
Mission milestones

January 2010
CryoSat shipped to Baikonur, Kazakhstan to begin launch campaign

September 2009
February 2010 target launch date announced

August 2009
Ground segment declared ready

February 2008
Prime instrument SIRAL rebuilt

February 2007
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: 22 January 2010