Under the new agreement signed on August 7, the two parties will construct and install a satellite laser ranging facility in the scientific base of Ny-Ålesund, Svalbard, with NASA providing also expert consultation on the operations.
"This partnership with Norway is an important step for NASA and the scientific community in building the next generation space geodetic network," said Benjamin Phillips, program scientist for NASA's Space Geodesy Program in Washington. "This network provides fundamental data for satellite and spacecraft navigation and underpins many of NASA's Earth-observing missions and science."
The ground-based laser transmits ultrashort laser pulses aimed at satellites specially equipped with a retroreflector, an array of special mirrors that bounce the pulses back. The system measures the time it takes for the light to travel back to its point of origin, which is used to determine the position of the satellite with respect to the ground station with an accuracy of around 0.04 inches (1 millimeter).
Combined with measurements from other geodetic instruments, the laser ranging observations will help refine the Global Geodetic Reference Frame, the basis for setting coordinates for all locations on Earth's surface, according to phys.org.
"From the NASA perspective, laser ranging is important to understanding where our spacecraft are, as well as where on Earth their measurements are located," explained Stephen Merkowitz, space geodesy project manager at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Laser ranging is needed for satellites that require very precise positioning measurements."
To make sure the laser ranging system is able to work in Arctic conditions, NASA will use a telescope dome strong enough to open and break the ice that might accumulate on top during Svalbard's frigid winters. The telescope will be mounted on a pointing gimbal that can still move when exposed to very cold temperatures. To be able to work during the Arctic summertime, when the constant sunlight makes it difficult to observe the stars needed to calibrate the telescope, NASA specified that this telescope has to be stable for months at a time.
"In Svalbard, we're already seeing the effects of climate change," said Per Erik Opseth, director of the Geodetic Institute of the Norwegian Mapping Authority in Hønefoss, Norway, the agency working with NASA to develop the new laser ranging system. "Setting up this fundamental station in Ny-Ålesund will help Earth observations from satellites crossing the North Pole, so we can improve our knowledge of ice cap meltdown, sea level rise in this area and also the melt of sea ice in the basin between Russia and North America."
The Norwegian Mapping Authority started construction work on the new scientific base in 2014. The current goal is to have all systems in operation by 2022.