An artistic rendering showcases the boundary layers between Earth's upper atmosphere and near-Earth space. Photo by NASA
Jan. 24 (UPI) -- With tomorrow's planned launch of the Global-scale Observations of the Limb and Disk mission, or GOLD mission, NASA scientists will be a step closer to understanding the thin, intermediate layers that form the boundary between Earth's atmosphere and space.
"This boundary region is increasingly more important to us because our infrastructure has grown out into space," Richard Eastes, GOLD principal investigator at the Laboratory for Atmospheric and Space Physics at the University of Colorado Boulder, told reporters during a conference call on Wednesday.
The behavior of the boundary layers -- part ionized, part not -- can affect drag on satellites and disrupt the signals they relay. The region is a highly dynamic place, influenced by terrestrial weather from below and space weather from above.
"We have some great models of this region of the atmosphere, but they're not accurate enough to do high quality prediction," Eastes said.
The region has proven difficult to study because it's too low for satellites travel through for long periods of time. Ground instruments can only observe a relatively limited portion of the boundary.
Scientists know the region features a high degree of variability, but they can't measure or predict it. According to NASA, better observations and predictions are necessary to protect GPS and other communications systems.
"We can literally wind up with bumps in the road because a lot of construction machinery is controlled by GPS," Eastes said of the boundary's potential impact on everyday systems.
The GOLD instrument is an image spectrometer.
"It captures both images and spectra, which means it captures all of the wavelengths in the area where the instrument is pointed," Eastes said. "And it's working in the ultra violet so it can see some really short wavelengths that our eyes don't see."
The instrument is hitching a ride into space aboard SES-14, a commercial communications satellite, which is scheduled to launch from French Guinea on Thursday. The GOLD mission will mark the first time NASA has attached a scientific instrument to a commercial satellite.
"This is a new paradigm that other science missions could and are following," said Elsayed Talaat, heliophysics chief scientist at NASA Headquarters in Washington. "It gives us, NASA, a new cost effective strategy for conducting science."
From its geostationary vantage point, the SES-14 satellite will provide communications services to South America while GOLD captures full-disk ultraviolet images of Earth's upper atmosphere. The images will reveal changes in temperature and atmospheric conditions in unprecedented detail.
"We've got tiny scan motors at the front of each spectrograph, and it moves the lens slowly across the face of the earth," said Susan Batiste, systems engineer at the Laboratory for Atmospheric and Space Physics. "It will produce a complete image of one half of the Earth every thirty minutes."
Scientists are particularly excited to study unique atmospheric waves that propagate up, impacting the boundary's behavior.
"These tides and wave can be forced upward by weather events over land and sea," said Katelynn Greer, GOLD research scientist. "It can be thunderstorms exploding up into the upper atmosphere, or just strong wind rippling off the tops of mountains."
The dynamics of the boundary layers can also impact the types of particles streaming down toward Earth. Research has shown some high-energy particles -- usually kept at bay by the ionosphere and Earth's electromagnetic fields -- can penetrate as low as an airplane's cruising altitude.
"These particles can trigger geomagnetically-induced currents that can affect our power grids," said Talaat.
Researchers say the GOLD mission has the potential to revolutionize scientists' fundamental understanding of near Earth space, offering new insights into the ways the sun's energy and space particles interact with gases in the upper atmosphere.
Unfortunately, the instrument won't start collecting and transmitting data for several more months.
"A few days after launch we will be turning on the instruments, opening the detector doors and exposing the instrument sensors to the vacuum of space," Batiste said.
But after that it's a waiting game until the satellite can assume the proper geospatial orbiting position and the communications systems can be brought online. NASA hopes to finally start doing some science in September.
