Space Agency’s Mission Aims To Uncover How Moons Of Mars Formed

Japan Aerospace Exploration Agency has announced a mission to Mars two moons and to return a sample of rock to Earth. This mission aims to unravel the mysteries of the moons origins and perhaps reveal how life began in the Solar System. Names of the Solar System’s planets are derive from Roman and ancient Greek mythology. Mars is the god war and the two red planet moons are name after the deity’s twin brothers, Deimos (meaning panic), and Phobos (fear).

Deimos and Phobos are smaller than our Moon. Phobos measures 22.2 km in diameter, and Deimos is only 13km. Both moons are in a stable orbit. Deimos is slowly moving away from Mars, while Phobos will reach the Martian surface within 20 million years.

Their gravity is too weak to pull the moons into spheres due to their small sizes. Instead, the pair has the irregular, lumpy structure typical of asteroids. This raises a question: Did they form from Mars? Or are they capture asteroids?

What Is The Difference Between Impact And Capture?

It is believed that our Moon was formed from material from Mars, which collided with the Earth’s early Earth. To form our Moon, material from the collision was flung into Earth’s orbit. Similar events could have created Deimos and Phobos. During the last stages of Solar System formation, the terrestrial planets were hit with a torrent of impacts.

Mars may have been the site of one such impact. The planet’s northern terrain is on average 5.5 km lower than its southern counterpart. This or other impacts could have caused the birth of the moons

Phobos and Deimos could also be asteroids, which were push inwards by Jupiter’s gravitational influence. The planet may have taken its moons, possibly by being pull in by Mars’s gravity. This is how Neptune obtained Triton, its moon. It is believe that Triton was once a Kuiper belt object similar to Pluto. Both the #TeamImpact scenario and the #TeamCapture scenario have compelling arguments.

Moons Orbit In The Same Plane Mission

Both moons orbit in the same plane as Mars’s rotation and are circular. Although the chances of this happening during a capture event is very unlikely, observations of the moons indicate that they could have a composition similar or even identical to other asteroids.

A clear determination of the composition of the moons would be a key to distinguishing the two models. Moons should made from the same rocks as Mars if there is a collision. If the moons had been capture, however, they would have formed in another part of the Solar System with different minerals.

Here is the new mission. JAXA’s Martian Moon eXploration Mission, (MMX), is schedule to launch in September 2024. It will arrive at Mars in Aug 2025. The spacecraft will spend the next three-years exploring the moons and the surrounding environment. MMX will descend to Phobos’ surface to collect a sample for return to Earth in 2029.

It is difficult to collect samples from small rocky bodies due to their weak gravity. This is JAXA’s specialty. In 2010, samples were return by JAXA from the asteroid Itokawa. Hayabusa2, the sequel to that mission is expect to reach asteroid Ryugu in 2012.

International Mission Collaborations

International participation in MMX has been strong due to the excitement surrounding a Mars moon mission. Naoki Okumura, president of JAXA, met Jean-Yves Le Gall, his counterpart at France’s Centre National d’Etudes Spatiales. This meeting established a partnership between the two space agencies. CNES will provide a tool for MMX and combine expertise in flight dynamics to help with the Martian moon encounter.

The French instrument will include a high-resolution, infrared camera as well as a spectrometer that analyzes the composition of each pixel. This will enable the investigation of rocks from the Martian moons down to just a few tenths a meter. The spectrometer has a pixel size that is an order of magnitude smaller then similar instruments on missions like NASA’s Mars Reconnaissance Orbiter or ESA’s Mars Express. This will allow MMX to select the best landing spot on Phobos and collect the sample.