…Orbital Sciences Corporation (NYSE: ORB) for NASA‘s ICESat-2 Earth observation mission. The NASA satellite is being designed, manufactured and tested by Orbital and is scheduled for launch in 2016. ICESat-2 will conduct critical measurements of Earth’s polar ice sheets. For Vienna-based RUAG Space, this contract represents a milestone in its expansion into the U.S. space market.
Among the many types of data being monitored and recorded from space, the observation of changes in the condition and extent of the ice sheets covering Greenland and the Antarctic is an important element in scientific studies to assess the global effects of climate change. The first U.S. satellite devoted to this task, ICESat-1, was taken out of service in February 2010 after seven years in operation. Since then, the continuity of the measurements has been assured by the Icebridge mission, which has been collecting airborne remote sensing data by means of a fleet of aircraft equipped with a wide variety of measuring instruments. As of 2016, these measurements will again be conducted from space by ICESat-2, which will be equipped with an advanced multi-beam laser altimeter system that is more powerful than that of its predecessor, ICESat-1. This improved precision laser-ranging technique will provide highly accurate measurements of ice sheet thickness, enabling scientists to produce high-resolution maps based on current topographical data.
An indispensable requirement for this kind of mission is the ability to keep precise track of the satellite’s position. Since ICESat-2 will be orbiting at the relatively low altitude of around 500km above the Earth’s surface, it can use navigation signals transmitted by the GPS system. RUAG Space in Vienna received a contract from U.S.-based Orbital to deliver two space-hardened GPS navigation receivers for the new satellite.
The design specifications for the GPS receiver call for an extremely lightweight device offering the highest possible component density while at the same time complying with all necessary requirements for reliability and resistance to radiation for deployment in space. Unlike the GPS receivers commonly used in terrestrial applications, these devices are capable of simultaneously processing signals received in two different frequency bands and thus delivering positioning information of the highest accuracy. This allows the instruments on board the satellite to provide data accurate to less than two meters, which can be refined to an accuracy of a few centimetres after processing by the ground station. This is the best performance available with today’s technology.
RUAG Space has built up its portfolio of GPS signal receivers in the course of numerous contracts awarded by ESA and the EC, especially in connection with the European SWARM, Sentinel 1/2/3 and EarthCARE missions. The two navigation instruments for the ICESat-2 mission are to be delivered in February 2014.
