The Mini Missions Aboard the Artemis Rocket Pack a Big Punch

Ten tiny satellites will be hitching a ride en route to the moon, each with scientific objectives of their own.

All eyes will be on the moon as the Artemis mission’s inaugural launch blasts toward our lunar neighbor in a couple of weeks, but the rocket won’t be the only new craft heading to space. After NASA’s Orion capsule separates from the Space Launch System (SLS) rocket, the SLS will deploy 10 tiny satellites, each about the size of a shoebox, which will then head off in different directions. The SLS will make for a deluxe ride into deep space for the probes, which researchers usually launch into low Earth orbit aboard much smaller rockets.

One of the miniaturized spacecraft, dubbed the Near Earth Asteroid Scout, will aim for a particularly distant target: It will swing past the moon en route toward a near-Earth asteroid, where it will take detailed images. The satellite will be propelled there by a sweeping solar sail. Despite its diminutive size, the NEA Scout, as it’s known for short, can do cutting-edge science while aiding the search for the kind of asteroid that future larger-class missions might want to visit.

“We want to image everything possible regarding the asteroid’s rotation, its size, its brightness, and its local environment,” says Julie Castillo-Rogez, a planetary scientist at NASA’s Jet Propulsion Laboratory and head of the NEA Scout science team. The spacecraft is equipped with a miniature yet top-of-the-line camera, similar in resolution to the one aboard NASA's OSIRIS-REx, a much larger asteroid-probing craft. “It’s very capable, but very small,” she says.

NEA Scout and its nine comrades demonstrate the many possible uses of nanosatellites known as CubeSats. Each is made up of sets of cubes that measure about 4 inches on a side. While some CubeSats are composed of three units in a row, called 3U, the spacecraft aboard Artemis 1 are 6U. 

The Capstone spacecraft, the first CubeSat launched as part of the Artemis program, is a 12U. Capstone launched in June and will scope out an orbit around the moon for the planned Lunar Gateway space station, which astronauts will assemble during future Artemis missions. All such satellites exploit miniaturized technologies and cram a battery, electronics, cameras, and other tools into an extremely compact space, enabling cheaper research than building larger spacecraft, which can cost hundreds of millions of dollars.

After the NEA Scout deploys from the SLS rocket, it will fly by the moon, and then slowly unfurl its solar sail several days later. Like everything else, the sail will initially be packed into a small box, fitting snugly into a third of the craft. But not for long. “As soon as we give that command, four metallic booms will pop open, pulling the sail off of a spool. It’s 925 square feet, roughly a school bus by a school bus,” says Les Johnson, head of the NEA Scout technology team at Marshall Space Flight Center.

The sail is coated with reflective aluminum that’s thinner than foil—like Saran Wrap but not sticky, Johnson says. Unlike a boat, the little spaceship’s sail will propel the craft when it catches rays of light, rather than gusts of wind. As light reflects off the sail, it gives up a little bit of energy, which is converted into an extra push on the sail and spacecraft.

The solar sail also counts as a technology demonstration for JPL: a possible propulsion system for flying a small probe not too far from the sun, without the risk of running out of fuel. It follows two predecessors that voyaged beyond Earth’s orbit: Japan’s Venus-bound Ikaros in 2010 and the Planetary Society’s Lightsail 2 in 2019.

After two years of sailing—sometime around September 20, 2024—NEA Scout will finally catch up with its target asteroid, called 2020 GE. At about 15 to 50 feet in size, it will be the smallest asteroid probed by a spacecraft. NEA Scout will slow down a bit as it approaches within 60 miles of the tumbling space rock, so that it floats by at a speed of around 45 miles per hour, allowing a few hours to take images. Then the spacecraft will continue on its way while 2020 GE continues along an orbital path that will bring it near Earth: Four days after its encounter with NEA Scout, the asteroid will hurtle past the planet, but at a safe distance of about 410,000 miles, or about 70 percent farther away than the moon is from us.

This CubeSat was one of the first that NASA officials picked in 2013 to launch on the SLS. The team had initially envisioned their project as a spacecraft that could scout for the kind of asteroid that might be explored by a future crewed mission, Castillo-Rogez says. No such mission is currently in the works, though NASA and other space agencies have been designing and launching robotic asteroid missions for years. Private space companies could also one day attempt to mine asteroids for lucrative minerals. 

The asteroid 2020 GE is also relevant to the planetary defense effort to monitor near-Earth objects. NEA Scout’s target is almost the size of the impactor that exploded as it fell to Earth in 2013, landing in Chelyabinsk, Russia. But it’s much smaller than potentially more dangerous space rocks, like the target of NASA’s asteroid-smashing spacecraft called DART, which will make its mark in late September or early October.

NEA Scout will travel with a variety of other little CubeSat companions. These secondary payloads, as they’re sometimes called, include NASA’s BioSentinel, which will use a biosensor containing yeast strains to measure how space radiation affects living organisms over long periods. The Italian Space Agency’s ArgoMoon will snap photos of the SLS second stage rocket and then of the moon’s surface. And the Japanese space agency’s Omotenashi will test “semihard” landing technology by deploying an airbag to gently crash—er, land—on the moon at about 110 mph.

Artemis 1 will also carry a commercial-led CubeSat: Lockheed Martin’s LunIR will use an infrared camera, kept at low temperatures by a micro-cryocooler, to map out the moon’s surface during day and night. (Lockheed was also NASA’s main contractor in building the Orion crew capsule, which sits atop the SLS.) Onboard Orion, Lockheed, Amazon, and Cisco have added a payload called Callisto—named after one of Artemis’s companions in Greek mythology—which includes a modified version of Alexa, the AI voice assistant, that can operate without internet access, and a customized version of Webex, the videoconferencing service, on a tablet. When astronaut crews ride aboard Orion on future flights, they could make use of such tools to take stock of their craft’s flight status and telemetry and to communicate by video.

Two more CubeSats—LunaH-Map and Lunar IceCube—will study water ice on the moon’s surface, both from a scientific perspective and because future lunar astronauts may attempt to extract some of that ice for water. “We’ve known for quite some time that there’s water ice at the moon’s poles, but there are a lot of unanswered questions about how much there is and where exactly it is,” said Craig Hardgrove, a planetary geologist at Arizona State University and the LunaH-Map lead, at a NASA press conference on Monday. With these projects, researchers aim to improve maps of lunar ice and to detect ice beyond the permanently shadowed craters, if it exists.

The Artemis 1 mission is tentatively scheduled to launch August 29, although NASA has reserved two backup dates in September. The agency had planned to launch as early as 2017, but the mission has been delayed multiple times. That has created some difficulties for its ride-along projects. Five of the 10 CubeSats, including the two that will study water ice, couldn’t easily be removed from the rocket for battery charging. Hardgrove thinks LunaH-Map’s battery is probably at around 50 percent, which he hopes will be sufficient to complete the mission.

On Tuesday, August 16, the SLS rolled out to the launchpad at Kennedy Space Center in Florida, where engineers will complete their final preparations and hook up power, propellant lines, and other systems. The NEA Scout team and their fellow researchers are excited about the upcoming liftoff and all the little missions that will fly along with it. After years of effort, and their SLS counterparts toiling away to create the biggest rocket ever sent into deep space, they’re looking forward to seeing all that work pay off, Johnson says: “I’m glad they’re giving me a ride.”

The Mini Missions Aboard the Artemis Rocket Pack a Big Punch

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