CryoSat-2

CryoSat-2 is a European Space Agency (ESA) Earth Explorer Mission that launched on April 8, 2010. CryoSat-2 is dedicated to measuring polar sea ice thickness and monitoring changes in ice sheets. Its primary objective is to measure the thinning of Arctic sea ice, but has applications to other regions and scientific purposes, such as Antarctica and oceanography.

CryoSat-2 was built as a replacement for CryoSat-1, which failed to reach orbit following a launch failure in October 2005. CryoSat-2 was successfully launched five years later in 2010, with upgraded software aiming to measure changes in ice thickness to an accuracy of ~10% of the expected interannual variation. Unlike previous satellite altimetry missions, CryoSat-2 provides unparalleled Arctic coverage, reaching 88˚N (previous missions were limited to 81.5˚N).

The primary payload of the mission is a synthetic aperture radar (SAR) Interferometric Radar Altimeter (SIRAL), which measures surface elevation. By subtracting the difference between the surface height of the ocean and the surface height of sea ice, the sea ice freeboard (the portion of ice floating above the sea surface) can be calculated. Freeboard can be converted to sea ice thickness by assuming the sea ice is floating in hydrostatic equilibrium.

CryoSat-2 is part of ESA's wider CryoSat mission in the Living Planet Programme. The spacecraft was constructed by EADS Astrium, and launched by ISC Kosmotras using a Dnepr carrier rocket.