Image caption: The surface of an unnamed lunar crater is strewn with rubble on Aug. 2, 1971. David Scott and James Irwin, two of four astronauts on the Apollo 15 mission, captured the image while exploring the Mons Hadley Delta region. Image courtesy of NASA.
Returning to the moon
With NASA, Buchanan was on a team of three interns. The others were in California and Ohio.
NASA sent them each a laptop. Their task was to help understand something called “multipath interference” in radio communication between a lunar orbiter and a ground station.
“Multipath interference specifically refers to the phenomenon when part of your signal bounces off something in the environment and bounces back to the receiver,” Buchanan explained. “So you’re receiving two of the same signal, but they’re sort of staggered. So that causes interference.”
Photo caption: Peter Schemmel. Photo courtesy of NASA.
Schemmel earned his doctorate in astrophysics at England’s University of Manchester, where the famed geophysicist Sydney Chapman ’58H (H denotes honorary degree) completed his studies decades before coming to the University of Alaska in 1953. Schemmel himself visited Fairbanks a few years ago to install one of NASA’s atmospheric propagation terminals on top of the Elvey Building. The instrument tracks changes in satellite signals caused by weather, useful when designing systems.
In NASA’s upcoming lunar missions, Schemmel said, maintaining communication with astronauts on the moon will be complicated.
Image caption: The Apollo 8 crew, the first to orbit the moon, captured this image of the far side of the moon in December 1968. Image courtesy of NASA.
To explore the problem of multipath interference, Buchanan’s intern team used a computerized simulator called the Multiple Asset Testbed for Research in Innovative Communication Systems, or MATRICS. It feeds information to the same communications hardware that would be used in a moon mission, Schemmel said.
“This testbed tricks that hardware into thinking it’s actually flying around the moon,” Schemmel said.