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.
Statements like this:
"Put more simply, NASA is going to fly Artemis II based on vibes, hoping that whatever happened to the heat shield on Artemis I won’t get bad enough to harm the crew on Artemis II."
Are just so intellectually dishonest and completely ignore the extensive research and testing that's gone into qualifying this flight.
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.
Sort of. At a certain threshold, everything is untested. I’d put this closer to modified than untested—the general config was tested in Artemis I and the specific configuration in a variety of ground tests.
Fixes have been made to the design, but they haven't been tested in flight.
So that means this capsule will fly a different re-entry profile to attempt to avoid the issue and Artemis IV will fly with untested fixes for lunar return.