Japan's upcoming mission will use a vacuum to get its sample from Phobos

Japan’s upcoming mission will use a vacuum to get its sample from Phobos

JAXA, the Japanese agency for the exploration of aerospace, is creating a niche for itself in return missions. Their Hayabusa mission was the first mission to test an asteroid when it brought dust from the asteroid Itokawa to Earth in 2010. Since its successor, Hayabusa 2took back a sample from the asteroid Ryugu 2020.

Now JAXA has the Moon Phobos in sight and will send a spacecraft to test it as soon as 2024. The mission is called Exploring Martian Moons (MMX), and it will use a pneumatic vacuum device to collect its samples.

Why go to Phobos and try it? Because it is an unusual moon and understanding it better could answer questions about it and our solar system. And we always want more answers.

Phobos is the largest of Mars’ two moons, the other being Deimos. Both moons are irregularly shaped and look like potatoes, especially Phobos. Phobos has an average radius of only 11 km (7 mi). It is closer to Mars than Deimos and orbits only 6,000 km (3,700 mi) from the planet’s surface. It moves fast, it only takes 7 hours and 39 minutes to complete one orbit and complete three orbits each day.

Much of Phobo's surface is covered with strange linear tracks.  New research reinforces the idea that boulders blasted off the Stickney crater (the large depression on the right) carved the iconic tracks.  Image credit: NASA / JPL-Caltech / University of Arizona
Much of Phobo’s surface is covered with strange linear tracks. New research reinforces the idea that the iconic tracks were carved by boulders that exploded free from the Stickney crater (the large depression on the right). Image credit: NASA / JPL-Caltech / University of Arizona

Phobos is probably a captured high-altitude asteroid, although astronomers are still discussing its nature. It has a lot in common carbonaceous asteroids and is one of the least reflective objects in the solar system.

The little moon is getting closer and closer to Mars. Every year it gets about 2 cm closer and will eventually be destroyed. In about 30 million to 50 million years, it will either hit the surface of Mars and be completely destroyed or torn apart by tidal forces and form a litter around the planet. In fact, one hypothesis states that Mars’ moons were formed by dust created by a giant impact on Mars. Dust to dust, as they say.

An illustration of Mars with a junk ring.  Image credit: SETI
An illustration of Mars with a junk ring. Image credit: SETI

Japan leads the MMX mission, but NASA, CNES (France) and DLR (Germany) also contribute. It has two overarching objectives: (1) to determine the origin of the Martian moons, and (2) to observe processes in Mars’ circumplanetary planetary environment, based on remote sensing, on-site observations, and laboratory analyzes of returned samples of Phobos regolith. Scientists believe that a better understanding of the Mars-Phobos-Deimos system will shed light on the planetary formation process in the solar system.

Getting a sample from Phobos encounters several obstacles. The moon is not massive enough for a spacecraft to enter orbit around it in the usual way. Instead, MMX will enter orbit around Mars and then perform quasi-satellite orbits. These tracks become unstable over time but should allow several months of operation near Phobos. This maneuver also allows the MMX lander to reach Phobo’s surface.

JAXA designed the MMX mission with three components: a propulsion module, an exploration module and the return module. The French space agency CNES suggested that the mission would also place a small rover about the size of a microwave oven on the surface, built by France and Germany.

But the highlight of the MMX mission will be the test return. We have made tremendous progress in sending instruments to spacecraft, landers and rovers to examine the bodies of the solar system. When it comes to Mars, the in-situ study of the planet has unleashed a flood of new evidence and insights. But the Holy Grail in space missions is still trial return. No matter how advanced the instruments we send on assignment are, laboratory analyzes on earth will always surpass them.

MMX will collect samples in two ways. One is the Coring Sampler (C-SMP) developed by JAXA. The other is the Pneumatic Sampler (P-SMP), contributed by NASA and developed by Honeybee Robotics.

The pair of samplers will complement each other and partly explain the fact that we do not know what the surface is like. The Coring Sampler will be placed on the lander’s robot arm. It will use a special shape memory alloy to collect a 10-gram sample from deeper than 2 cm below the regolith.

P-SMP can capture regolith even if the surface is covered with gravel-sized material.  (Image credit: Honeybee Robotics)
P-SMP can capture regolith even if the surface is covered with gravel-sized material. (Image credit: Honeybee Robotics)

The pneumatic sampler will be placed near the footplate on one of the lander’s legs. It will use pressurized nitrogen to collect the samples, and contract operators can manipulate the gas flow depending on the requirements. It can be either continuous or pulsed.

This is a schematic view of P-SMP with 1. Sampling head, 2. N2 gas and sample return pipe and 3. Control box with a sample container.  (Image credit: Honeybee Robotics)
This is a schematic view of P-SMP with 1. Sampling head, 2. N2 Gas and sample return pipes and 3. Control box with a sample container. (Image credit: Honeybee Robotics)

P-SMP has three sets of nozzles to perform the procedure. Two digging nozzles point downwards, two retro-pressure nozzles point upwards and two transport nozzles point towards the sampling pipe. The three nozzle pairs light up simultaneously.

The excavation nozzles fire against the surface of Phobos and stir up material from the regolith. The transport nozzles lead material into the sampling head. The retro-pressure nozzles fire to counteract the traction of the spacecraft, so its position is stable during sampling.

Honeybee Robotics has tested its P-SMP extensively and is convinced that it can handle all surprises on Phobo’s surface. The company says its system can still collect a sample even if gravel covers the surface.

MMX will not be the only mission to use Honeybee’s vacuum system. NASA plans to use it on the moon to capture lunar regoliths in Mare Crisium in 2023. The system is also being considered for a Europa Lander mission and several other missions that are still in the concept and design phase.

It’s easy to understand why.

“The purpose of this technology is to allow easy and inexpensive capture of planetary materials from virtually unknown surfaces,” said Honeybee project manager Kris Zacny. “Vacuum cleaners are designed to catch” dirt “, therefore a vacuum cleaner-like method is ideal for working with planetary” dirt “.

More:

#Japans #upcoming #mission #vacuum #sample #Phobos

Leave a Comment

Your email address will not be published.