The icy expanse of Greenland was evident in this photo from the cockpit of NASA ER-2 No. 806 as it cruised at 62,000 feet altitude on its transit flight to Iceland April 2.

NASA's ER-2 high-altitude environmental science aircraft arrived in Keflavik, Iceland late on April 2, 2012 to begin a series of flights over the next five weeks that are intended to validate the accuracy of a new laser altimeter named MABEL.

MABEL, an acronym for the Multiple Altimeter Beam Experiment Lidar, was developed at NASA's Goddard Space Flight Center to simulate a similar instrument planned for NASA's IceSat-2 environmental satellite that is scheduled for launch in 2016. Credit: NASA/Tim Williams

› Link to associated news item