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Japan tests probe to land on Martian moon Phobos, bring a chunk of it back to Earth

COVID hiccups be damned, work on instruments and connectivity is under way and space agency JAXA is determined to hit launch window

The world’s first mission to collect samples from Phobos, one of two moons orbiting Mars, has progressed to testing its bus system and mission instruments.

Work on the mission - Japan Aerospace Exploration Agency (JAXA)’s Martian Moons eXploration (MMX) - was detailed in an article in which spacecraft system lead engineer Takane Imada said evaluations of the spacecraft’s instruments and bus system, which provides essential functions such as electric power, communication, attitude control and more, were almost completed.

Next comes “structural tests, electrical/mechanical interface check to check the mechanical and electrical compatibility between the bus system and mission instruments, and [electromagnetic] tests using an engineering model to check the functions, performance, durability, and others,” outlined Imada.

After those milestones, the mission will have to test the spacecraft’s connection with ground systems. All tests are scheduled for completion by the end of fiscal year 2023, at which point the spacecraft will be transported to Tanegashima Space Center.

The goal of MMX is to gather information that could help determine whether Mars’ two moons are captured asteroids or fragments of a celestial body that hit Mars at one point in time.

The spacecraft will orbit Mars, transfer to Phobos, land and gather at least ten grams of samples from the moon, before making several flybys of smaller moon Deimos and sending a return module with the samples back to Earth.

“Exploring Martian moons could help uncover new findings to clarify the evolution process of the Solar System, including how the planets were born and shaped," said mission engineer Hirotaka Sawada.

Sawada knows a bit about collecting samples from celestial bodies, having previously worked on the MMX predecessor known as the Hyabusa-2 mission to asteroid Ryugu.

But while Hayabusa-2 had a 40 cm diameter capsule for samples, MMX has a 60 cm version. And MMX won’t simply brush up against Phobos as Hayabusa did at Ryugu. This mission will land, meaning it needs more fuel. In turn, instruments will have to be lighter to account for all the fuel the spacecraft will have to lug around the inner solar system.

The mission is expected to launch in September 2024, land on Phobos in August 2025 and return to Earth in July 2029.

Building MMX was complicated by COVID-19, which delayed travel to see hardware under development by manufacturers. The lead engineer said the team is currently rearranging schedules to make up for delays.

"We cannot feel relaxed during the period from this testing phase to the launch of the spacecraft,” said Sawada. “If we miss the launch opportunity, we will have to wait another two years for the next attempt.” Sawada added the team may encounter troubles but will just have to “press forward.” ®

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