Moon & Mars Mondays · your week on the Moon and Mars

From The Decisional Pass

When a programme runs late you can change three things: the hardware, the schedule, or what you asked for. The third costs nothing and is the one nobody wants to touch, because requirements are where everybody's carefully argued worst case is written down.

Last week NASA touched it twice.

Take some of it off the suit

Eric Berger reported at Ars Technica on September 2 that NASA will work with Axiom Space on a "Sortie Suit," a stripped-down AxEMU, for the first landings. Artemis programme manager Jeremy Parsons directed it. The goals are to cut mass, cut complexity, and simplify how the suit mates to the landers from SpaceX and Blue Origin. Jeff Foust confirmed the change at SpaceNews a day later, adding that NASA is pouring extra resources into Axiom to protect the Artemis IV date.

Look at what the original spec asked for. Six spacewalks across a 6.5-day mission. After sitting dormant in storage, the suit still had to be good for more spacewalks 210 days later. Its thermal system had to run nominally for two hours inside a permanently shadowed region, about the coldest place anyone has stood.

Every one is defensible on its own. Together they are a mass budget nobody can close. You answer cold with layers, layers make the suit stiff, stiff costs the mobility that was the point, and the thing gets heavier, harder to build and later. NASA's inspector general called the requirements "over-burdensome" in 2024. Collins Aerospace walked away from its suit contract that same year, leaving Axiom as NASA's only provider.

At last week's Aerospace Safety Advisory Panel meeting, former astronaut Charlie Precourt said NASA leadership is now meeting Axiom six days a week, often in person. His line was careful and completely clear: "Requirements are being adjusted to reflect near-term mission needs, including shortening the spacesuit certification duration requirements."

That is a programme deciding it wants a good-enough suit in 2028 more than a perfect one later.

Nine spots instead of a hundred

The same panel got the other half.

The base of Orion is 186 blocks of Avcoat, and on Artemis I a lot of them lost chunks of char. The root cause: the material was effectively impermeable. It couldn't breathe. Avcoat gasifies as it ablates and heat keeps soaking deeper, so material underneath is still outgassing while the surface is busy, and if that gas can't vent, pressure builds and cracks pieces off. Artemis I's skip entry stretched the event out and made it worse.

NASA decided not to rebuild the Artemis II shield, which was already installed, and flew a steeper non-skip entry instead. Higher peak heating, but far less time in the regime where the outgassing happens.

The numbers, presented to the panel at Ames: Artemis I had more than 100 char loss sites, some more than an inch deep. Artemis II had about nine. Paul Hill, the former director of Mission Operations, called the shield's condition "highly satisfying."

They paid for it, and this is the part I keep chewing on. The steeper profile cut Orion's downrange capability from 4,800 nautical miles to about 1,775. Downrange is how far you can fly from entry interface before you splash, and it's the margin you spend when weather at the landing site turns bad. Ninety percent fewer divots, bought with two thirds of your ocean.

The permanent fix is in the material. Avcoat is now made more permeable so it vents instead of trapping, and Hill says that should restore the downrange too. It flies first on Artemis III next year.

Meanwhile in the VAB

SLS hardware kept moving at Kennedy. Both boosters have their centre segments mated, and all four RS-25 engines are now on Core Stage-3, finishing the job that started in late August. Artemis III is the low Earth orbit flight that tests rendezvous and docking against lander pathfinders from both providers. The landing is Artemis IV, targeted for 2028. That is the date the suit is chasing.

Eight places to look for life

On the Mars side, Tianwen-3 has a shortlist. Chief scientist Hou Zengqian said the team cut 86 candidate landing sites down to eight, weighing geological age, water history, habitability, and how well each site would preserve a biosignature. The final choice comes before year's end, with the spacecraft already in prototype build.

The plan is unchanged and still remarkable: launch around 2028 on two Long March 5 flights, one with the lander and ascent vehicle, one with the orbiter and return module, and bring home at least 500 grams around 2031. Sampling is by drill to two metres down, a first at Mars, plus a drone that fetches material away from the lander so the landing plume hasn't already stirred it.

The two-metre number is the whole thesis. Mars has been worked over by radiation and oxidation for a very long time, so if organics survived it's under a couple of metres of cover. ESA's Rosalind Franklin reached that conclusion years ago and launches toward Oxia Planum in 2028 carrying a two-metre drill. Two agencies, no coordination, same depth.

China is also standing up what it calls the world's first planetary protection laboratory to handle the samples on arrival. Which tells you they take the science objective literally.

References

• Wary of Artemis IV timeline, NASA is changing lunar spacesuit design — Ars Technica, Eric Berger, 2 September 2026
• NASA revising requirements to keep Artemis spacesuit on schedule — SpaceNews, Jeff Foust, 3 September 2026
• It turns out that Orion's much-maligned heat shield performed really well — Ars Technica, Eric Berger, 1 September 2026
• Artemis III SLS stacking advances as Orion results confirm trajectory fix — NASASpaceflight, 7 September 2026
• China narrows Tianwen-3 Mars sample return landing site selection, seeking traces of life — SpaceNews, Andrew Jones, 4 September 2026
• Tianwen-3 mission enters prototype phase, prioritizing search for Martian life traces: chief scientist — Global Times, 3 September 2026
• Chinese scientist details first planned Mars sample-return mission Tianwen-3 — The State Council of the PRC, 23 July 2025
• NASA Outlines Preliminary Artemis III Mission Plans — NASA, 13 May 2026

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