NASA’s Artemis II uses lasers to send 4K video back from the Moon

How Artemis II returns a superb video of the moon

New laser system aboard NASA’s Orion spacecraft sends sharper video and more data back to Earth

By Adam Bluestein edited by Eric Sullivan

NASA launched four astronauts on a pioneering journey around the Moon: the Artemis II assignment. Follow our coverage here.

Like the Artemis II Mission headed for a flyby of the moon, Orion’s crew module is testing one of NASA’s most ambitious space communications improvements ever: a laser system called O2O. Abbreviation of Orion Artemis II optical communications systemO2O caps more than two decades of work by NASA and the Massachusetts Institute of Technology’s Lincoln Laboratory to build better, high-bandwidth links for deep space. The system is designed to send data to Earth at speeds of up to 260 megabits per second, far faster than the radio links previous missions relied on. Scientific American I spoke with some of the developers of the system about how it works.

Let there be light

“Since the beginning of NASA, we’ve used what’s called microwave communications, frequencies typically in the gigahertz range,” says Greg Heckler, deputy director of NASA’s Space Communications and Navigation (SCaN) program, which funded the O2O system. The Orion crew capsule will actually use this ancient technology as its primary communications system, connecting to the Near Space Network and Deep Space Network of giant radio antennas spread across the world.

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NASA has spent the last two decades developing optical communications systems. By using bursts of infrared light (rather than microwaves) from a laser to encode data, these systems can move much more information than traditional systems and can often do so with a smaller, lighter device.

Key components of the O2O design have already been validated in a series of demonstrations dating back over a decade. THE Lunar Laser Communication Demonstration in 2013 showed record download speeds from the Moon to Earth, while more recent missions, like the TeraByte infrared delivery (TBIRD) on a CubeSat in low Earth orbit and the Deep Space Optical Communications (DSOC) experiment on the spaceship Psyche– have pushed laser links towards higher data rates and longer distances. For more than two years, an optical terminal almost identical to that of Orion has been operating on the International Space Station. “In each case, we set new data throughput records,” says Heckler. “O2O will be our final gem of the demo series.”

The O2O, which is about the size of a house cat, is expected to achieve data rates of up to 260 megabits per second to Earth and 20 megabits per second to Orion. “I think you’d be happy if this was your home Internet connection,” Heckler says. The lag is due to Orion’s considerably smaller optical receiver.

For two-way video chats, this translates to about a second of round-trip lag. “It’s noticeable,” Heckler says, “but not what I would call an obstacle.” The ability to have two-way conversations in real time will be essential as the Artemis program evolves toward a more continuous human presence on and around the Moon. “Think about what it means to be able to videoconference with your family for an astronaut on the moon who might find themselves in a stressful situation,” says Heckler.

An improved information pipeline will also allow scientists on Earth to regularly receive critical mission data from the flight recorder rather than having to wait for Orion to land to retrieve it. In the future, seamless two-way connectivity could also allow scientists to remotely pilot rovers and monitor critical lunar infrastructure.

Ready, aim, shoot

The laser used in the O2O module is nothing particularly sophisticated, as lasers say. “We rely to a large extent on what the fiber optic telecommunications industry uses for their lasers and transmitters,” says Bryan Robinson, group leader in optical and quantum communications at MIT Lincoln Laboratory, which built the O2O terminal. In this case, it is a solid-state laser in the same non-visible infrared wavelengths used in telecommunications. Erbium-doped fiber amplifiers increase this laser to approximately one watt of optical power emitted through the aperture.

By the time a laser beam from Orion reaches Earth, about 384,400 kilometers away, its diameter is about 6 kilometers. “Take a laser pointer that has an aperture of a few millimeters,” says Robinson. “Over a distance of several tens of feet [a few meters]it looks like a tiny dot on a screen. But if you were to propagate this out into space, after traveling 400,000 kilometers like we do, it would be much bigger than the beam I just described.

From the Moon, a 6 km target is tiny. “The most important technical challenge of the mission is pointing the laser with sufficient precision,” says Robinson. The O2O module transmits data to ground stations in New Mexico and California, where dry air and minimal cloud cover help preserve the link. “Ultimately, to make the connection, you need that score to be right to the thousandth of a degree.”

Achieving these goals accurately requires knowing exactly where is the Orion spacecraft and how it is oriented, which is not easy in space. While the star trackers mounted on Orion indicate where the vehicle is pointing, potential misalignments between the star trackers and the communications terminal can only be fully measured and corrected once in space. “We carefully measure our alignment with star trackers,” says Robinson. “But even the distance between star trackers and the spacecraft’s Orion terminal can introduce distortions due to temperature and other factors that degrade our pointing ability.”

To aim the laser, the O2O system uses a 10-centimeter telescope mounted on a two-axis gimbal, which can rotate through a full hemisphere of motion to acquire its target. Background optics (light-focusing lenses, tracking sensors, rapid-orienting mirrors, and other components) refine the laser beam. “As long as the spacecraft points us in the right hemisphere, everything should be fine,” Robinson says. But there are wild cards, including potential obstructions from Orion’s solar panels or the spacecraft’s body and uncertainty about the vehicle’s ability to maintain a consistent orientation. “We think the first time we try to point the system, we’ll learn something about the vehicle that you can’t really learn until you’re up there and cruising,” Robinson says.

There will be a brief power outage to all communications systems as Orion passes behind the moon. But on future Artemis missions, relay satellites could help bridge this gap on the far side of the Moon.

For the public, however, the most obvious reward is seen in the sharper video that O2O sends home from Orion’s 28 cameras. The system transmits 4K video as well as photographs, scientific data and voice communications. “The camera is the mission,” Heckler says. “We want to make sure we give back to American citizens with this 4K video.”