| ▲ | russdill 2 hours ago | |||||||||||||||||||||||||||||||
I mean, that's how these heat shields work. They aren't reusable, you can't test them and then use them again. Or do you mean the design? We already did Artemis I. | ||||||||||||||||||||||||||||||||
| ▲ | palata an hour ago | parent | next [-] | |||||||||||||||||||||||||||||||
See this recent blog post about it (I am not the author): https://idlewords.com/2026/03/artemis_ii_is_not_safe_to_fly.... It says that it is not safe to fly. They are sending humans without having tested in real conditions that their design was sound, GIVEN that the first time they did that (without humans), it turned out that their design was unsafe. | ||||||||||||||||||||||||||||||||
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| ▲ | adamsb6 an hour ago | parent | prev | next [-] | |||||||||||||||||||||||||||||||
I mean the design. They've changed the AVCOAT to be less permeable and altered the re-entry profile. One of the findings of Artemis I is that lack of permeability led to trapped gas pockets which expanded and blew out pieces of heat shield. The reason for the change to be less permeable is to make it easier to perform ultrasonic testing, not to improve performance. They altered the re-entry profile on the theory that the skip period contributed to spalling, but Charles Camarda disagrees in this doc: https://docs.google.com/document/d/1ddi792xdfNXcBwF8qpDUxmZz... > Another chart which the Artemis Tiger Team did not intend to show on Jan. 8th, was the figure showing the spallation events as a function of time during the skip entry heating profiles (Figure 6.0-4 of NESC Report TI-23-0189 Vol. 1). In this figure, it was quite clear that the Program narrative they were feeding to the press, that it was the dwell time during the skip which allowed the gases generated to build up and cause the delta pressures which caused most of the spallation was, again, patently false. In fact, during the first heat pulse (t ≈ 0 to 240 sec), approximately 40-45% of all the medium to large chunks of ablator spalled off the Artemis I heatshield. > Hence, varying the trajectory would do little to prevent spallation during Artemis II. I was never shown the new, modified trajectory at the Jan. 8th meeting. | ||||||||||||||||||||||||||||||||
| ▲ | 4khilles 2 hours ago | parent | prev | next [-] | |||||||||||||||||||||||||||||||
The heat shield is a bit different, and the reentry profile is a bit different as well. | ||||||||||||||||||||||||||||||||
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| ▲ | wat10000 an hour ago | parent | prev [-] | |||||||||||||||||||||||||||||||
We already did Artemis I and the heat shield lost a lot more material than it was supposed to on that flight. "Specifically, portions of the char layer wore away differently than NASA engineers predicted, cracking and breaking off the spacecraft in fragments that created a trail of debris rather than melting away as designed. The unexpected behavior of the Avcoat creates a risk that the heat shield may not sufficiently protect the capsule’s systems and crew from the extreme heat of reentry on future missions." Fixes have been made to the design, but they haven't been tested in flight. | ||||||||||||||||||||||||||||||||