A partial image of the moon.

Future moon landing will leave U of M ‘footprint’

Physicist Keith Goetz developing instruments for new lunar investigations

MINNEAPOLIS/ST. PAUL (07/17/2019) — The University of Minnesota will contribute instruments to a series of 12 new NASA investigations on the moon in preparation for landing astronauts there in 2024. The payloads will be delivered aboard three landers as part of NASA’s Artemis lunar program. Seven will be devoted to planetary science and heliophysics, five to demonstrating new technologies. Launches are tentatively set to begin in 2021.

The U of M project, led by physicist Keith Goetz, will be part of the Lunar Surface Electromagnetics Experiment (LuSEE), which will carry out extensive measurements of electromagnetic phenomena on the lunar surface. The principal investigator for LuSEE is U of M College of Science and Engineering alumnus Stuart Bale (M.S. Physics '92, Ph.D. '94), now a professor at the University of California Berkeley’s Space Sciences Laboratory.

“One cool part is that if we put our instruments on the moon, they’ll be there forever,” Goetz says. “We’ll land at daybreak on the moon and spend the next two weeks, that is, one lunar daytime, taking data at the landing site. When the sun sets on the lander, the batteries will shut down, probably ending the mission.”

With a short timeline and a modest budget (less than $6 million), the LuSEE team is re-using hardware left over from previous NASA missions: the Parker Solar Probe FIELDS experiment, launched last August; the STEREO/WAVES mission, launched in 2006; and the MAVEN Mars mission, launched in 2013.

The new missions, announced July 1, are part of the NASA’s Commercial Lunar Payload Services program, which on May 31 commissioned three startup companies to build lunar landers.

If all goes as planned, the astronaut landing in 2024 will be historic in more ways than one: It will mark the return of humans to the lunar surface after a 52-year absence, and it will land the first woman, or women, on the moon. 

LuSEE in the sky

LuSEE will examine the moon’s fluctuating magnetic field and the dust stirred up by impacts of light and electrons from the sun. One instrument, a sophisticated radio receiver, will become the first operating radio telescope on the moon. Another instrument that will make the trip is the TDS (time domain sampler), which Goetz and his team designed. It measures waves of particles and light and records the most interesting data.

The moon makes an ideal plasma physics laboratory for Goetz, Bale and their colleagues. It exists in an essentially perfect vacuum and has neither magnetic field nor atmosphere to interrupt the stream of charged particles from the sun—the solar wind—a subject of intense interest to the scientists. Because the solar wind impinges on the lunar surface, instruments there can easily measure it directly.

LuSEE instruments will also measure impacts from lunar dust, a material of practical and medical, as well as scientific, concern.

“Photoionization by sunlight gives dust grains an electric charge,” says Goetz. “If the grains are fine enough, the charges can levitate the dust off the lunar surface.”

The charges also lead to “static cling” that can make the dust difficult to wipe off a spacesuit. Worse, never exposed to wind or rain, even fine lunar dust has sharp edges that make it dangerous to handle and even more dangerous to inhale.

Despite their brief two-week lifetime, the missions have much to teach scientists. Says Goetz: “We’ll learn how to build observatories on the moon.”