Low-cost optical terminals

NASA’s primary ground stations for optical communications on Artemis II were telescopes at the White Sands Complex in Las Cruces, New Mexico, and the Table Mountain Facility in California. However, the space agency also decided to test whether it would be feasible to deploy a lower-cost optical terminal on the ground to receive lasers from space.

Engineers from NASA field centers in Ohio and Maryland purchased an off-the-shelf 70 cm telescope from Observable Space and a backend to process the lasers from Quantum Opus. Within months, the telescope and detector were deployed at Mount Stromlo in southeastern Australia, near Canberra.

During Artemis II, the off-the-shelf optical terminal reached the system-designed maximum rate of 260MB per second, downloading much of the data NASA received during the mission.

“Advancing US leadership in space- and ground-based optics is core to our mission, and turn-key laser communication ground stations are a critical component of that future,” Dan Roelker, co-founder and CEO of Observable Space, said in a statement.

The technology for receiving and processing laser signals from the Moon, Mars, or beyond is not simple. The “Opus One” detection system, for example, uses superconducting nanowire single-photon detectors. That’s why reducing the cost of building and deploying these systems is critical for widespread adoption of space-to-ground laser communications.

Quantum Opus was co-founded by physicist Josh Cassada, who became a NASA astronaut in 2013 and then retired more than a decade later to rejoin Quantum Opus. He led the fabrication of the company’s photon-detection products.

In an interview, Cassada said the technology is important not just for getting massive amounts of data down from space, but also for applications such as quantum computing. “If you want to detect photons at the single photon level, and you don’t know anything about cryogenics, that’s fine,” he said. “You just push this button, and in three hours, you’re counting photons.”