NASA and Japan’s space agency JAXA have selected a new low-cost sample collection technology for 2 missions to the Moon and the Martian moon Phobos.
PlanetVac, developed by Altadena, California-based Honeybee Robotics and funded partially by Planetary Society members and supporters, is scheduled to fly to the Moon in 2023 and to Phobos in 2024. The Moon flight comes courtesy of a NASA program to fund commercial lunar landers and payloads, while the trip to Phobos will be aboard JAXA’s Martian Moons eXploration (MMX) mission. PlanetVac is a NASA contribution to MMX and will be one of two sample acquisition systems that collects a sample from Phobos that will be returned to Earth.
“We’re thrilled that our members and supporters have helped enable a technology that will collect samples from the Moon and Phobos,” said Bruce Betts, The Planetary Society’s chief scientist. “PlanetVac demonstrates that providing public-supported seed funding at key times can serve a critical role in moving technologies closer to use in space flight.”
The samples PlanetVac collects can be analyzed with on-board science instruments, returned to Earth, or both. The Planetary Society’s science and technology program sponsored tests of PlanetVac in 2013 and 2018.
Although its name implies something akin to a household vacuum cleaner, PlanetVac works by blowing gas into a planetary surface, stirring soil and rock up into a collection chamber. In its simplest form, PlanetVac attaches to a spacecraft’s lander leg, meaning the device is ready to work as soon as the lander touches down. The system requires as little as one moving part: a valve that opens to release the gas.
“PlanetVac seeks to greatly simplify the way we collect samples on other worlds,” said Kris Zacny, the vice president of exploration systems at Honeybee Robotics. “We designed the system to be flexible for a wide variety of applications, and we’re already demonstrating that by flying it on two very different missions.”
The lunar version of PlanetVac will launch in 2023 aboard a yet-to-be-selected lander under NASA’s Commercial Lunar Payload Services (CLPS) program, which supports the agency’s plans to return humans to the lunar surface. CLPS pays private companies to build, launch, and fly landers to the lunar surface carrying NASA and commercially developed science and technology payloads. Some of these payloads, including PlanetVac, are meant to demonstrate promising new technologies in support of future missions.
PlanetVac’s lander will touch down in Mare Crisium—the Sea of Crises—a fish-shaped dark splotch visible from Earth on the Moon’s northeast corner. NASA is considering two landing sites: one near a crater that resembles the fish’s eye in the west, and another near the fish’s tail in the east. The only other mission to Mare Crisium was the Soviet Union’s Luna 24 spacecraft, which returned samples from the region’s southern area in 1976.
Once on the Moon, PlanetVac will release a burst of gas into the surface and verify sample collection success using a small camera and laser-based measurement system. The system will also sieve the sample into different grain sizes, which is required for certain types of scientific analyses. Because PlanetVac is being included as a technology demonstration aboard the spacecraft, the samples will not be analyzed or returned to Earth.
Japan’s MMX spacecraft will launch to Phobos in 2024 and return samples from the Martian moon to Earth in 2029. MMX has two sampling mechanisms: a robotic-arm-mounted coring device called C Sampler that will drill into Phobos’ surface, and a version of PlanetVac on a lander leg called P Sampler—short for Pneumatic Sampler. NASA is providing P Sampler and another science instrument called MEGANE to the mission.
P Sampler is similar to the version of PlanetVac NASA is flying to the Moon, with the added capability of pushing the samples up a tube into a canister. Planetary Society supporters funded laboratory tests of this technique in 2013.
Once MMX departs Phobos, the spacecraft’s robotic arm will move the canister into a sample return container with the samples collected by the C Sampler. As MMX approaches Earth, it will release the sample return container, which will plummet through Earth’s atmosphere and use a parachute to land safely for collection.
Scientists hope the samples MMX collects will reveal whether Phobos formed after a large impact on Mars, or whether it is a captured asteroid of the same type that brought water to Mars and Earth long ago. Honeybee is scheduled to deliver the lunar PlanetVac to NASA in late 2021 or early 2022, and the P Sampler to Japan’s space agency JAXA in 2022.
More testing ahead
More Earth-based testing for PlanetVac is also coming: As soon as later this year, the technology will take flight on a Masten Xodiac rocket in the Mojave Desert. The Planetary Society provided funding for a similar test flight in 2018 for which a PlanetVac-equipped Xodiac made a short hop into a box of simulated Martian soil. After PlanetVac collected a sample, Xodiac hopped away and landed again, demonstrating the system could withstand an end-to-end flight aboard a real rocket. For next year’s Xodiac test, PlanetVac will perform the additional step of sending the sample up a tube to the top of the rocket, just as it will do on Phobos.