MMX launches tonight: Japan's mission to bring back rock from the Martian moon Phobos – with Europe on board

Key facts about MMX

• Launch: Monday 19 October 2026 at 19:41 UTC (20:41 in the UK, 21:41 in central Europe) – Tuesday 20 October at 04:41 in Japan.
• Rocket and site: H3 Flight No. 10 (H3 F10) from the Yoshinobu Launch Complex, Tanegashima Space Center.
• Back-up window: 21 October to 7 November 2026.
• Goal: at least 10 grams of material from Phobos, back on Earth in 2031.
• Rover: Idefix weighs 25 kg on Earth but only about 15 grams on Phobos.
• Partners: JAXA (lead), NASA, CNES, DLR and ESA.

When exactly does MMX launch?

According to JAXA's press release of 20 August 2026, lift-off is set for 04:41:03 Japan Standard Time on 20 October. Because Japan is nine hours ahead of UTC, it will still be Monday evening in Europe. ESA confirmed the time on 13 October: 20:41 BST, 21:41 CEST.

As of Sunday 18 October, the launch was still listed as scheduled on JAXA's MMX website. If it slips, JAXA has reserved a window from 21 October to 7 November, and the launch time may change within it.

What is MMX, and what is on board?

The spacecraft is built from three modules – propulsion, exploration and return – and stands 5.3 metres tall, 9.0 metres long and 4.5 metres wide, according to JAXA. ESA says the main spacecraft carries seven science instruments plus a radiation monitor, two high-resolution cameras and two sampling devices. Together with the rover, that makes 11 science instruments in all.

The samples will be shared among the partners, and European scientists will be able to apply to study them.

Why sample Phobos rather than Mars itself?

Phobos is the larger of Mars's two moons. It measures 27 × 22 × 18 kilometres and circles Mars three times a day, according to NASA. Creeping 1.8 metres closer each century, it will either crash into Mars or break up into a ring in roughly 50 million years.

As of October 2026, nobody knows for sure where Phobos came from. ESA outlines two leading ideas: it may be an asteroid captured by Mars's gravity, or debris thrown up by a giant impact on Mars. If the second is true, the samples could also tell us about the history of Mars itself.

“The data and samples returned by MMX are a window to study the evolution of Mars and the Solar System,” says Elliot Sefton-Nash, ESA's project scientist for MMX.

The 10-gram target is roughly double the 5.4 grams or so that Japan's previous sample-return mission, Hayabusa2, brought back from the asteroid Ryugu, according to JAXA (December 2021).

What is the Idefix rover, and what is Europe contributing?

Idefix is a compact rover built by CNES in collaboration with DLR. It carries four instruments, will help prepare the main spacecraft's landing and will examine what the surface is made of and how it is structured. Phobos's gravity is so weak that the 25 kg rover weighs only about 15 grams there.

How the rover will land

According to DLR (September 2026), Idefix will be dropped from a height of 40 to 100 metres, bounce a few times and then turn itself upright. Its science phase is expected to last about three months, with operations run from DLR's control centre in Cologne and from CNES in Toulouse.

DLR built the RAX Raman spectrometer, which will analyse the surface composition, and the miniRAD radiometer, which measures surface temperature. CNES supplied the cameras and the rover's central computer, power and communications. Rovers on other worlds are nothing new – NASA already uses AI to navigate on Mars – but on Phobos the vehicle weighs next to nothing.

Can I see Mars from Norway right now?

Yes, though not during the launch. Our own calculation with NASA/JPL Horizons shows that Mars is below the horizon in Oslo at 21:41 on Monday. The planet rises in the north-east shortly after midnight.

• Best time: the early hours of Tuesday 20 October, when Mars stands about 41 degrees above the south-eastern horizon at 06:00.
• What to look for: a reddish point of light at about magnitude +1.0, similar to a moderately bright star, in the constellation Cancer.
• Distance: about 229 million kilometres from Earth.

Those same pre-dawn hours bring shooting stars too: the Orionids peak before dawn on Thursday 22 October. For more sky events visible from Norway, see our Astronomy section.

What happens next? The timeline to 2031

JAXA calls MMX the largest international lunar and planetary mission Japan has ever led, and it is one of the highlights of the 2026 space year. According to ESA and JAXA, the plan is:

1. 19/20 October 2026: launch from Tanegashima (back-up window until 7 November).
2. August 2027: arrival in Mars orbit after a cruise of about a year.
3. September 2027: the spacecraft settles into a quasi-satellite orbit around Phobos and studies both Phobos and Deimos from a distance.
4. Early 2029: Idefix is dropped onto Phobos.
5. 2030: the main spacecraft lands and collects samples – JAXA plans two soft landings – before leaving the Martian system.
6. 2031: a capsule carrying the samples lands in Australia and is flown on to Japan.

Frequently asked questions

When does MMX launch, and when will the Phobos samples reach Earth?

Launch is planned for Monday 19 October 2026 at 19:41 UTC (20 October, 04:41 in Japan). The sample capsule is due to land in Australia in 2031.

What is MMX, and who is behind it?

MMX (Martian Moons eXploration) is a Japanese spacecraft that will explore the moons of Mars and bring back samples from Phobos. JAXA leads the mission, with NASA, CNES, DLR and ESA as partners.

Why is JAXA collecting samples from Phobos rather than Mars itself?

The origin of Phobos is unresolved: it could be a captured asteroid or the remains of a giant impact on Mars. The samples should settle the question and may also shed light on the history of Mars.

How much material will MMX bring back?

At least 10 grams, according to ESA – roughly twice what Hayabusa2 returned from the asteroid Ryugu.

What happens if the launch is delayed?

JAXA has reserved a launch window from 21 October to 7 November 2026, and the launch time may vary within that period.