idlewordsMar 31

Artemis II is not safe to fly

https://idlewords.com/2026/03/artemis_ii_is_not_safe_to_fly.htm

Artemis II Is Not Safe to Fly (Idle Words)

Show threadbsilvereagleMar 31

> “Our test facilities can’t reach the combination of heat flux, pressure, shear stresses, etc., that an actual reentering spacecraft does. We’re always having to wait for the flight test to get the final certification that our system is good to go.”—Jeremy VanderKam, deputy manager for Orion’s heat shield, speaking in 2022

This is a strange claim, considering NASA used to have 2 facilities that were capable of this - one at Johnson and one at Ames. They were consolidated (https://ntrs.nasa.gov/api/citations/20160001258/downloads/20...) but it seems like the Arc Jet Complex at Ames is still operational https://www.nasa.gov/ames/arcjet-complex/

Show threadidlewords
The Orion heat shield is sixteen feet across. NASA's test facilities can only test small material samples in these facilities, not capture how the entire heat shield will behave.
Mar 31 at 4:12amWeb
Show threadsillysaurusxMar 31
How does SpaceX test it? Have they needed to solve this problem?
Show threadrkagererMar 31
By blowing up unmanned spacecraft and letting the ones that survive catch fire?
Show threadmargalabargalaMar 31
SpaceX tests these in prod. Kinda like Artemis I did.
Show threaderuMar 31
And this is actually a decent strategy, but you can only really do this when you have lots of unmanned flights.
Show threadidlewordsMar 31
They do iterative flight testing. Starship is I believe on its twelfth flight test; the first one was in 2023.
Show threadhvb2Mar 31

By having a much higher launch cadence and then analyzing the flight hardware afterwards.

Also, they don't have anything human rated going beyond LEO. Coming back from the moon means you're going significantly faster and thus need a better heat shield

Show threadSyzygyRhythmMar 31
There were 19 successful unmanned Dragon 1 missions before Crew Dragon, and an unmanned Crew Dragon mission before the first crewed one (actually two missions, but one didn't reenter from orbit). The heat shield material and design was essentially the same and so there was a great deal of flight heritage.