![\"\"](\"https:\/\/cdn.arstechnica.net\/wp-content\/uploads\/2024\/05\/orion-char.jpg\")
<\/p>\n
The inspector general\u2019s report, released on May 1, 2024, included new images of Orion\u2019s heat shield.<\/p>\n
Credit:
\n NASA Inspector General<\/p>\n<\/figure>\n
Convened in a ninth-floor conference room at NASA Headquarters known as the Program Review Center, the meeting lasted for more than three hours. Isaacman attended much of it, though he stepped out from time to time to handle an ongoing crisis involving an unwell astronaut on orbit. He was flanked by the agency\u2019s associate administrator, Amit Kshatriya; the agency\u2019s chief of staff, Jackie Jester; and Lori Glaze, the acting associate administrator for NASA\u2019s Exploration Systems Development Mission Directorate. The heat shield experts joined virtually from Houston, along with Orion Program Manager Howard Hu.<\/p>\n
Isaacman made it clear at the outset that, after reviewing the data and discussing the matter with NASA engineers, he accepted the agency\u2019s decision to fly Artemis II as planned. The team had his full confidence, and he hoped that by making the same experts available to Camarda and Olivas, it would ease some of their concerns.<\/p>\n
What followed was a spirited discussion, with Camarda sparring regularly with the presenters and Olivas asking questions more infrequently. The engineering team in Houston, led by Luis Saucedo, went through dozens of charts and presented reams of data that had not been made public before.<\/p>\n
,<\/p>\n
\u201cThat level of openness and transparency is exactly what should be expected of NASA,\u201d Isaacman said after the meeting.<\/p>\n
\u201cWhat if we\u2019re wrong?\u201d<\/h2>\n
Perhaps the most striking revelation was what the NASA engineers called \u201cwhat if we\u2019re wrong\u201d testing.<\/p>\n
At the base of Orion, there are 186 blocks of a material called Avcoat, individually attached to provide a protective layer that allows the spacecraft to survive the heating of atmospheric reentry. Returning from the Moon, Orion encounters temperatures of up to 5,000\u00b0 Fahrenheit (2,760\u00b0 Celsius). A char layer that builds up on the outer skin of the Avcoat material is supposed to ablate, or erode, in a predictable manner during reentry. Instead, during Artemis I, fragments fell off the heat shield and left cavities in the Avcoat material.<\/p>\n
Work by Saucedo and others\u2014including substantial testing in ground facilities, wind tunnels, and high-temperature arc jet chambers\u2014allowed engineers to find the cause of gases becoming trapped in the heat shield, leading to cracking. This was due to the Avcoat material being \u201cimpermeable,\u201d essentially meaning it could not breathe.<\/p>\n
After considering several options, including swapping the heat shield out for a newer one with more permeable Avcoat, NASA decided instead to change Orion\u2019s reentry profile. For Artemis II, it would return through Earth\u2019s atmosphere at a steeper angle, spending fewer minutes in the environment where this outgassing occurred during Artemis I. Much of Thursday\u2019s meeting involved details about how the agency reached this conclusion and why the engineers deemed the approach safe.<\/p>\n A test block of Avcoat undergoes heat pulse testing inside an arc jet test chamber at NASA\u2019s Ames Research Center in California. The test article, configured with both permeable (upper) and non-permeable (lower) Avcoat sections for comparison, helped to confirm an understanding of the root cause of the loss of charred Avcoat material on Artemis I.<\/p>\n Credit: However, toward the end of the meeting, the NASA team agreed to discuss something that \u201cno one really liked to talk about.\u201d This was an analysis of what would happen to Orion if large sections of the heat shield failed completely during Artemis II. Formally, this is known as a \u201cdamage tolerance evaluation,\u201d the engineers said. Informally, it\u2019s known as \u201cWhat if we\u2019re wrong.\u201d<\/p>\n ,<\/p>\n The Avcoat blocks, which are about 1.5 inches thick, are laminated onto a thick composite base of the Orion spacecraft. Inside this is a titanium framework that carries the load of the vehicle. The NASA engineers wanted to understand what would happen if large chunks of the heat shield were stripped away entirely from the composite base of Orion. So they subjected this base material to high energies for periods of 10 seconds up to 10 minutes, which is longer than the period of heating Artemis II will experience during reentry.<\/p>\n What they found is that, in the event of such a failure, the structure of Orion would remain solid, the crew would be safe within, and the vehicle could still land in a water-tight manner in the Pacific Ocean.<\/p>\n \u201cWe have the data to say, on our worst day, we\u2019re able to deal with that if we got to that point,\u201d one of the NASA engineers said.<\/p>\n The composite layer beneath the heat shield is intended to withstand a maximum temperature of 500\u00b0 F during reentry. During Artemis I, the maximum temperature recorded, despite the persistent cracking and char loss, was 160\u00b0. So any crew on board would have been safe. Even so, the heat shield damage was a serious concern because the agency\u2019s modeling did not predict it.<\/p>\n After more than two years of testing and analysis of the char loss issue, the NASA engineers are convinced that, by increasing the angle of Orion\u2019s descent during Artemis II, they can minimize damage to the heat shield. During Artemis I, as the vehicle descended from about 400,000 to 100,000 feet, it was under a \u201cheat load\u201d of various levels for 14 minutes. With Artemis II, this time will be reduced to eight minutes.<\/p>\n Orion\u2019s entry profile will be similar for the first two and a half minutes, but afterward, the Artemis II entry will undertake a bit of a higher heat load than Artemis I for a couple of minutes. All of the agency\u2019s modeling and extensive arc jet testing indicate this will produce significantly less cracking in the Avcoat material.<\/p>\n ,<\/p>\n Much of the discussion Thursday delved into the technical minutiae of heat shields, tamp planes (the process of packing Avcoat into blocks), early char loss, spallation, and more. The discourse also revealed that one test in 2019, three years before Artemis I, indicated hints of the char loss later observed in flight. But this finding was not unequivocal, nor did it throw up a huge red flag at the time, the NASA officials said.<\/p>\n Technicians inspect the heat shield for the Artemis II launch.<\/p>\n Credit: The message from Isaacman, Kshatriya, and other NASA officials at the meeting was clear. This heat shield was not perfect. If NASA knew several years ago what it knows now, the heat shield would be designed differently. It would be permeable to prevent the outgassing problems. Those changes are being incorporated into the Artemis III mission\u2019s heat shield. There will be other tweaks to increase reliability.<\/p>\n Nevertheless, the agency is confident that flying the Artemis II heat shield on the revised profile is perfectly safe. In NASA jargon, such a rigorous justification that a space mission is safe to fly is known as flight rationale.<\/p>\n But why get to flight rationale at all? About 18 months ago, as the agency was narrowing in on the root cause of the heat shield issues, NASA\u2019s leaders at the time, including Kshatriya, considered their options. They mulled the possibility of flying Artemis II in low-Earth orbit to test its life support equipment but not overly stress the heat shield. They thought about flying a second robotic mission around the Moon.<\/p>\n Perhaps most seriously, they considered moving forward with the Orion spacecraft (or at least its heat shield) that will be flown in Artemis III, which has permeable Avcoat, to be used for this mission. I asked Kshatriya on Thursday why they had not simply done this.<\/p>\n \u201cWe had considered \u2018let\u2019s just pull forward CSM 3 (the Artemis III spacecraft),\u2019\u201d he said, in part. \u201cand essentially turn CSM 2 (Artemis II) either into a test article or something else. Again, CSM 3 has unique capabilities, docking systems on it, right? We didn\u2019t have a docking mode for that mission (Artemis II). CSM 2 could not be retrofitted with the docking system because of the uniqueness of the tunnel. Really, CSM 2 is kind of uniquely a free return vehicle because of the way it was designed initially. So the mods that would have had to be made for (Artemis) II and III to do that swap would have been too odious, and we wouldn\u2019t have gotten the learnings. And, you know, we\u2019re trying to get up hill as quickly as we can.\u201d<\/p>\n ,<\/p>\n Given all of this, how should we feel about this flight rationale, with Artemis II potentially launching in early February?<\/p>\n Over the last 18 months, I have had many discussions with experts about this, from mid-level engineers and current and former astronauts to senior leaders. I know definitively that the four Artemis II astronauts, Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen, are comfortable with the decision. They did not feel that way at the beginning of the process. Wiseman, in particular, was quite skeptical. But they\u2019ve been won over. Like almost everyone else who has reviewed NASA\u2019s data at length, they accept the plan. Indeed, they are ready and eager to fly.<\/p>\n But what of the outside critics? That was the whole point of Thursday\u2019s session. Could the NASA engineers convince Olivas and Camarda?<\/p>\n Olivas flew two Space Shuttle missions in 2007 and 2009 and has an advanced degree in materials science from Rice University. Before this week\u2019s meeting, he had not gone public with his heat shield concerns. But he has been talking to me and another space reporter, Robert Pearlman, for about a month now.<\/p>\n Olivas is very credible on these issues. He was asked by the NASA leadership in late 2023, before the independent review team was formally named, to provide a second set of eyes on the space agency\u2019s heat shield work. He saw all of the investigative data in real time. Although not formally a member, he sat in on the review team\u2019s meetings through 2024 before that process ended. Afterward, he had some lingering questions he felt were unresolved by that process. A few weeks ago, he told Pearlman and me he would be reluctant to fly on Orion. It was a stunning admission.<\/p>\n Isaacman appeared to take these concerns seriously. In advance of Thursday\u2019s meeting, he engaged with Olivas to hear him out and share information about what NASA\u2019s engineers had done over the last 18 months to resolve some of the independent review team\u2019s questions. These included char loss very early in Orion\u2019s reentry.<\/p>\n ,<\/p>\n After Thursday\u2019s meeting, Olivas told me he had changed his mind, expressing appreciation and admiration for the in-depth engineering work done by the NASA team. He would now fly on Orion.<\/p>\n Camarda, another former shuttle astronaut, was less effusive. He has been very public with his criticism of NASA\u2019s handling of the Orion heat shield. He told me in December 2024 that the space agency and its leadership team should be \u201cashamed.\u201d Unlike Olivas, however, he has been on the outside the whole time. NASA had kept Camarda, 73, at arm\u2019s length, and he felt disrespected. Given his credentials\u2014the aerospace engineer spent two decades working on thermal protection for the space shuttle and hypersonic vehicles\u2013Camarda could be a potent voice of skepticism leading up to the Artemis II launch.<\/p>\n After the meeting, I asked Camarda whether he felt any better about flying crew on the Artemis II heat shield.<\/p>\n \u201cI would never be happy accepting a workaround and flying something that I know is the worst version of that heat shield we could possibly fly and hoping that the workaround is going to fix it,\u201d Camarda said. \u201cWhat I really hope he [Isaacman] gets is that if we don\u2019t get back to doing research at NASA, we\u2019re not going to be able to help Starship solve their problems. We\u2019ve got to get back to doing research.\u201d<\/p>\n But Camarda was no longer the firebrand he was at the outset of the meeting. Near its end, in fact, he even thanked the leadership team for being brought in, read in on the data, and allowed to have his say.<\/p>\n","protected":false},"excerpt":{"rendered":" WASHINGTON, DC\u2014This week, NASA\u2019s new administrator, Jared Isaacman, said he has \u201cfull confidence\u201d in the space agency\u2019s plans to use the existing heat shield to protect the Orion spacecraft during its upcoming lunar mission. Isaacman made the determination after briefings with senior leaders at the agency and a half-day review of NASA\u2019s findings with outside […]<\/p>\n","protected":false},"author":1,"featured_media":44084,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[7856,720,190,640,21],"class_list":["post-44082","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-heat-shield","tag-jared-isaacman","tag-nasa","tag-orion","tag-space"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/44082"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=44082"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/44082\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/44084"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=44082"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=44082"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=44082"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/cdn.arstechnica.net\/wp-content\/uploads\/2026\/01\/jsc2024e078233medium.jpg\")
<\/p>\n
\n NASA<\/p>\n<\/figure>\nGetting to \u201cflight rationale\u201d<\/h2>\n
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<\/p>\n
\n NASA<\/p>\n<\/figure>\nYes, and maybe<\/h2>\n