At 3 a.m. on Wednesday morning, a group of students trudged to the south side of University Park Campus, flicked some equipment to life and prepared to start their shift. From the dark side of the Earth, they could now directly track the Orion spacecraft on its mission to the Moon. 

As with all missions to the Moon, Artemis II must contend with what is known as a three-body problem: the spacecraft is caught between the gravitational fields of Earth, the Moon and the Sun. 

The computational power needed to constantly track and refine the frequencies of communications in a three-body problem is immense, which has led NASA to outsource some of this tracking and measuring to institutions like USC. 

“Everybody sees the four heroes and all their things that are happening, [but] in all honesty, we’re talking thousands and thousands of people; engineers and scientists and technicians that have been supporting all this,” said David Barnhart, the director and co-founder of USC’s Space Engineering Research Center. “For us, it’s sort of cool to be just a really small part of that sort of beehive of activity.”

Artemis II is the second of five missions in the Artemis program, the end goal of which is to establish a lunar base, set a cadence for annual Moon missions and ultimately lay the foundation for a mission to Mars. 

Artemis I was a flight of an unmanned variant of the Orion spacecraft, while Artemis II is the first manned mission to the moon in over half a century. Artemis III is a test flight of commercial landers from SpaceX and Blue Origin, which will be used in Artemis IV to transfer astronauts from the Orion spacecraft to the Moon’s surface.

The students’ work is part of a class led by David Barnhart, a research professor of astronautics in the department of astronautical engineering. Barnhart said the tracking is helped in large part by the spacecraft’s Doppler effect. 

The Doppler effect is the phenomenon where frequencies increase as they move toward an observer and decrease as they move away; a speeding car gets louder as it gets nearer, and quieter as it gets farther. 

Barnhart’s group measures the Doppler shift of the Artemis II to constantly refine the frequencies used for transmissions of photos, spacecraft diagnostics or voice communication. These refinements can only be made while their equipment is facing the Artemis II, which is between the hours of midnight to 7 a.m. The data generated by the group’s refinements will be sent to NASA and used in future Artemis missions. 

“What we’re trying to do is to help NASA tune the communications that come back and forth from the spacecraft, so [for] future missions it locks in and is able to track specific frequencies,” Barnhart said. “If you’re not on the right frequency and they’re sending a picture, you’re only going to get three quarters of the picture.”

Barnhart said that spaceflight is at an “inflection point” where spacecrafts are beginning to be maintained and prepared for longer lifespans instead of being used once, and infrastructure is being developed to sustain ecosystems in space, both around the Earth and on the Moon.