‘We’re on the moon’ — Blue Ghost lander now has 14 days to learn all it can

Firefly Aerospace becomes first commercial company to make fully successful landing on the moon

The Mini Cooper-sized Blue Ghost lander that touched down on the moon today carries lots of interesting technologies, but chief among them are the crumple cartridges in its landing legs and the prototype of a small, radiation resilient computer of a kind that could ride on spacecraft headed to the moon or Mars.

The lander, built by Firefly Aerospace in Texas, depended on the crumple cartridges to make sure the spacecraft settled into a reasonably level position if it had touched down on a slope or rock in Mare Crisium, a plain thought to have few such obstacles. An initial, low-resolution image displayed during the company’s livestream indicated the spacecraft was safe and upright.

The landing came at 3:34 a.m. Eastern time at a velocity of about 1 kilometer per hour. A live display on the Firefly website showed three of the four footpads turning blue, indicating that sensors detected contact by three of them. A few seconds later, Firefly’s mission operations reported, “Y’all stuck the landing; we’re on the moon,” and the Austin control room erupted in cheers. A narrator declared that Blue Ghost, funded in part under NASA’s Commercial Lunar Payload Services program, had achieved the first fully successful landing by a commercial spacecraft. The Intuitive Machines Odysseus tipped over as it touched down near the south pole last year, but operated for the planned seven days before being enveloped by the lunar night.

The initial Blue Ghost image did not make clear why only three of the footpads turned blue, but it did appear to show some nearby rocks. Landing at a severe angle would have jeopardized the ability of one of its instruments to drill into the surface and for another to collect samples of the regolith for onsite analysis.

• Did you know? Firefly Aerospace named Blue Ghost after a rare species of firefly that glows blue-green, rather than the more common yellowish-orange of other species.
• Popular destination: Blue Ghost is one of three commercial landers scheduled to land on the moon in the coming weeks. The Intuitive Machines Athena, which like Blue Ghost was funded partly by NASA under its Commercial Lunar Payload Services program, is scheduled to land March 6. The Resilience lander, made by ispace of Japan, was launched on the same rocket as Blue Ghost in January and is scheduled to land in late May or early June.
• Watch the post-landing press conference here.

Each leg contains a “crush core cartridge” made of honeycombed aluminum designed to crumple to a degree that’s determined by the force exerted on each leg, said Ray Allensworth, Firefly’s spacecraft program director, before the landing.

Early indications are that the legs worked as planned, which means that the onboard experiments will have 14 days of sunlight and a few hours of darkness after the lunar sunset to run various experiments, including a bunch with RadPC, the prototype computer. The mission will end shortly after because of the lack of sunlight to generate electricity.

The roughly Rubik’s Cube-sized RadPC computer is the culmination of 18 years of research and design work by a succession of 150 Ph.D. students at Montana State University in Bozeman, where RadPC was built.

Previous iterations of RadPC were flown on a high-altitude balloon and in space seven times, says Brock LaMeres, a computer engineering professor at Montana State University who leads the project. Versions rode in low-Earth-orbiting satellites and aboard the International Space Station.

As valuable as those experiments were, there’s nothing like the moon. “Being on the surface is a good test because it shows you what a computer would have to endure when you actually get on the surface,” LaMeres says. “We’re kind of curious that when we’re not facing the sun, will we see radiation from other stars?”

RadPC is designed to operate continuously through “single event effects” such as encounters with cosmic rays and high-energy protons emanating from the sun. These can cause a “bit to flip” in a logic circuit, turning a one into a zero or vice versa, LaMeres says. Single event effects don’t permanently damage a computer’s hardware, but if they occur in a CPU, they can cause it to lock up and have to reboot.

To withstand this radiation, mission-critical computers for space have typically been built with oversized circuits from specialized materials, which makes them expensive and slower-operating. Small satellite computers can’t be oversized, so bit flips are typically dealt with by rebooting often.

RadPC takes a different approach: Inside are four inexpensive, off-the-shelf computer cores that operate redundantly with one another. If a logic circuit is disrupted in one of them, then the unaffected cores can continue to operate uninterrupted while the damaged core’s hardware and software is autonomously taken offline and reconfigured to its original state. RadPC also has redundant memory and a “housekeeping chip” that autonomously makes repairs as needed.

RadPC also carries three dosimeters that monitored radiation levels as Blue Ghost passed through Earth’s radiation belts during the elliptical orbits that preceded its landing. The dosimeters will now measure radiation on the lunar surface.

The computer has operated continuously and sent data back about its repair procedures and radiation levels throughout the mission so far, LaMeres says. At the end of the lunar day, Blue Ghost is expected to send back data for a few hours of nighttime before it shuts down, which is when RadPC would have a chance to operate with the moon blocking the sun’s radiation.