Japan will launch a spacecraft on the world’s first mission to bring back samples from Phobos, one of two small potato-shaped moons orbiting Mars. Scientists hope the mission, which is expected to last five years, will provide clues about how Phobos and its younger brother Deimos formed and hopefully even shed light on the origins of life in the solar system. The Japan Aerospace Exploration Agency (Jaxa) aims to launch the spacecraft on Tuesday over a new Japanese pillar. H3 rocket. Yasuhiro Kawakatsu, project manager for the Martian Moons eXploration (MMX) mission, said the Phobos samples would provide useful data for scientists to consider using a Martian moon as a base for a future manned mission to the planet. The United States, China and other countries hope to send astronauts to Mars. “Despite their potential importance, Martian moons have never been thoroughly investigated,” Kawakatsu said. “They are known as the most important unclimbed mountains in the solar system.” Japan leads an international mission, including equipment and communications support from NASA and other national space agencies. Since the 1960s, dozens of missions have been sent to Mars, but its moons remain largely a mystery. Multiple Russian attempts to land on Phobos, including one launched in 2011, have failed. Phobos and Deimos take their names from the Greek mythological personifications of fear and terror, sons of the god of war Ares, whose Roman counterpart is Mars. A key question is how they were formed and what they are made of. Some scientists believe the two irregular, cratered bodies could be debris formed after a large celestial object crashed into Mars. Others say the moons could be asteroids that come from other places. Jaxa officials believe the Phobos samples will provide answers. “We can almost certainly reach a conclusion by analyzing soil samples,” said Kiyoshi Kuramoto, the mission’s principal investigator. Jaxa unveiled the spacecraft for its mission to the Martian moon at the Tanegashima Space Center in August. Photograph: Yuika Kawazoe/Kyodo News/APS Scientists chose to collect samples from Phobos mainly because the moon is closer to Mars than Deimos and therefore they may have more information about the planet. Material from Mars is expected to make up about 0.1% of the material collected from Phobos, Jaxa officials say. Phobos is about 27 kilometers (17 miles) in diameter at its widest point and orbits Mars at a distance of about 6,000 kilometers (3,700 miles) three times a day. The Phobos samples could also shed light on the origin of Deimos, as the two moons were believed to have similar roots, Kuramoto said. The mission includes plans to fly over Deimos and collect observations. It will be a long journey to reach the red planet, which is 55 million kilometers from Earth at its closest point. The actual flight distance would be 500 to 600 meters, Kawakatsu said. After launch on the H3 rocket, the spacecraft will arrive in the Mars region around August 2027. It will then fly near and around Phobos for three years to collect data and samples from the moon, before returning home in 2031. MMX is made up of three modules, for propulsion, exploration and return. Only the third module will return home with the samples. The spacecraft will carry 13 instruments, including a rover jointly developed by France and Germany that will land on the moon, as well as a NASA sampling device and an instrument for measuring gamma rays, and the European Space Agency’s deep space communication device. A Japanese radiation monitor will collect data that can help in future manned exploration of Mars. The Franco-German Idefix rover will arrive first at Phobos. During a 100-day mission around 2029, it will explore the surface to assist in subsequent sampling of Japanese soil. The spacecraft will choose a relatively flat and level site for its landing based on topographic data provided by the rover. Once the MMX mission lands, Jaxa scientists aim to collect at least 10 g (0.35 oz) of soil from the moon in two sampling attempts using American and Japanese methods. NASA’s sampling device uses pressurized gas to lift surface dust into a container, and Jaxa’s coring method will collect samples to a depth of about 2 cm. On the first attempt, the MMX will collect surface and underground samples using both devices, and take additional underground samples on the second landing. Scientists say collecting samples from multiple locations increases the chances of obtaining any potential traces of past microbial life on Mars. Landing on the pockmarked moon, which has only two-thousandths of Earth’s gravity, is a challenge. To minimize bouncing upon landing, the MMX’s exploration module is equipped with four-legged landing gear with shock-absorbing features. The rover has wheels that can gain traction in low-gravity conditions, right themselves if it tips over, and move “at a snail’s pace,” according to Jaxa. The samples will be stored in a heat-protected capsule designed to survive re-entry into Earth’s atmosphere. The module is expected to land in Australia before being sent back to Japan.
