Laser Systems Will Enable NASA Satellite to Measure Sea Ice
- Monday, 01 August 2011
Flight lasers and test laser
Managed by NASA’s Goddard Space Flight Center in Greenbelt, MD, the Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) mission is scheduled to launch in 2016. The satellite will replace the original ICESat observatory, which was decommissioned in 2010. Four flight lasers and one test laser for ICESat-2’s Advanced Topographic Laser Altimeter System instrument will be provided by Fibertek.
In contrast to the original ICESat design, ICESat-2 will use a micropulse, multi-beam, photon-counting approach that provides dense cross-talk sampling to resolve surface slope on an orbit basis. The instrument consists of a single laser beam split into nine beams. It features 10-m ground footprints, multiple detector pixels per spot, and an onboard boresight alignment system. A laser reference system provides absolute laser pointing knowledge. The sensor will have a high pulse repetition rate of 10 kHz, which generates dense along-track sampling of about 70 cm.
The ICESat-2 mission is to quantify polar ice-sheet contributions to current and recent sea-level change and the linkages to climate conditions, and to quantify regional signatures of ice-sheet changes to assess mechanisms driving those changes. It is designed to improve predictive ice sheet models; estimate seaice thickness to examine ice/ocean/ atmosphere exchanges of energy, mass, and moisture; measure vegetation canopy height as a basis for estimating large-scale biomass and biomass change; and enhance the utility of other Earth observation systems through supporting measurements.
This concept has advantages over ICESat including improved elevation estimates over high slope areas and very rough areas, and improved lead detection for sea ice freeboard estimates. ICESat-2 will measure the topography of the Greenland and Antarctic ice sheets, and the thickness of Arctic and Antarctic sea ice.