June 4, 2014
NASA Testing Space Laser Capable Of Precisely Collecting Earth Elevation Data
redOrbit Staff & Wire Reports - Your Universe Online
The laser instrument component of NASA’s Ice, Cloud and land Elevation Satellite-2 (ICESat-2) is currently being integrated and tested at the Goddard Space Flight Center in Maryland, US space agency officials announced on Tuesday.
The instrument, which is known as the Advanced Topographic Laser Altimeter System (ATLAS), will be used to measure the elevation of the planet’s surfaces, including forests, oceans and even ice sheets. It will be outfitted with six beams, that combined will generate a more detailed elevation picture than the signal beam utilized by its predecessor, the original ICESat that was operational from 2003 through 2009.
ATLAS is part of a black box structure that was constructed from a composite honeycomb material so that it can be extremely light. It includes an opening that allows the lasers to beam to Earth, as well as additional windows large enough for a telescope that will be used to capture photons that bounce off of the planet and return to the probe.
The structure was precisely measured and labeled in order to denote where other instruments, including mirrors, photon detectors and other electronic equipment would be attached. NASA noted that it had to be strong enough to make it through a rocket launch unscathed, as well as surviving multiple years in the harsh environments of space.
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Last month, it was relocated to a clean room at Goddard, where it is currently being integrated by a group of 250 scientists, engineers and fabricators, the space agency explained. The entire process, which will take approximately two years, will ensure that the box structure is capable of withstanding tests designed to simulate those conditions.
“There’s lots of activity, we’re moving from looking at all the different subsystems, to looking at the overall system coming together. It’s really exciting to move forward into that realm,” said Cathy Richardson, instrument manager with the ICESat-2 mission, whose team will have six components ready to be delivered by month’s end. “It’s not just a drawing. It’s an actual, real piece of hardware, that’s getting tested and showing that it’s meeting requirements.”
According to NASA, ATLAS beams light with a green laser that fires pulses 10,000 times per second. While only a handful of those photons will rebound and return to the satellite, they can be counted using an extremely sensitive detector. By recording how long it takes the photons to return, the NASA scientists are able perform calculations to determine the distance the photons traveled and, as a result, the height of the Earth below ICESat-2’s orbit.
Thanks to the laser instrument, scientists will be able to collect measurements that create a global portrait of the planet’s elevation, as well as track climate-related changes such as thinning sea ice and melting glaciers more precisely. ATLAS is one of the many ways in which the satellite will observe our world in unique new ways, which the space agency said will be challenging from a technical standpoint but could lead to unimaginable discoveries.
“ICESat-2 will revolutionize our understanding of ice sheet and sea ice changes and processes,” said project scientist Thorsten Markus. “I think it’s one of the most exciting missions out there. There’s so much opportunity for real discoveries.”