Launch set for Tanegashima

Japan's space agency JAXA plans to send the Martian Moons eXploration (MMX) spacecraft into space on a new H3 rocket from the Tanegashima space centre. Deutsche Welle and the BBC name Monday, 19 October, as the launch day, while NZZ and The Independent give Tuesday, 20 October, so the date is reported inconsistently. Deutsche Welle puts the liftoff at 21:41 Central European Time, whereas The Verge gives 2:41PM Eastern time for the same launch. The H3 is meant to become a central launch vehicle for Japan, and Mitsubishi Heavy Industries builds it.

A first return trip to the Mars system

If the mission succeeds, it would be the first time a sample has been returned from Mars or its moons for analysis in laboratories on Earth, according to the BBC. The spacecraft is due to reach Mars orbit in August 2027, where it will circle Phobos before attempting a landing on its surface. Deutsche Welle reports that it is to gather at least 10 grams of material during a roughly three-year stay in the Mars system. The sample capsule is set to return to Earth in 2031, and the project is expected to last five years in total, according to The Independent. Kiyoshi Kuramoto, the MMX principal investigator, said the team can almost certainly reach a conclusion from analysing the Phobos soil.

Origins of the two moons

Phobos and Deimos are both small and irregular, with Phobos about 20 km across and Deimos about 10 km, according to the BBC. Scientists disagree about their origin: one idea holds that a large celestial body struck Mars and the moons formed from the debris, while the other holds that they are asteroids pulled in by Mars's gravity. Phobos was chosen as the sample target mainly because it orbits closer to Mars than Deimos and may carry more information about the planet, JAXA officials said. About 0.1% of the material collected from Phobos is expected to come from Mars itself, JAXA officials say. Kuramoto added that samples from Phobos could also shed light on Deimos, since the two moons are believed to share similar roots.

Landing on a tiny moon

The MMX spacecraft will study Deimos as it arrives and then focus on Phobos, and it plans to set down a small rover named Idefix to scout a landing site. Idefix is a co-production of the German aerospace centre DLR and France's CNES, and once on the surface it will deploy a robotic arm and two samplers to collect moon dust. The sample material will be packed into a small capsule that lands in the Woomera desert of South Australia in 2031. Sara Russell, a Natural History Museum scientist and deputy for sample analysis on the mission, described the overall plan in the BBC interview.

“I think this is an incredibly ambitious and fun mission.”

Japan's role in the wider race

The mission underlines Japan's rise as a space power, according to NZZ, with companies such as Canon, Honda and the startup Interstellar Technologies also pursuing launch projects. NASA and other national space agencies provide equipment and communications support for the Japan-led mission, according to The Independent. The United States, China and others are considering sending astronauts to Mars, which gives the Phobos samples added weight for future crewed missions. Yasuhiro Kawakatsu, the MMX project manager, said the moons have never been fully investigated.

“Despite their potential importance, Martian moons have never been fully investigated.”