Before and after photographs show test results of heating Avcoat material for 660 seconds. – NASA<\/div>\n<\/figcaption><\/figure>\n
This phase of flight, called \u201creentry,\u201d causes a violent compression of air molecules that can heat the spacecraft\u2019s exterior to more than 5,000 degrees Fahrenheit (2,760 degrees Celsius).<\/p>\n
NASA engineers designed the Orion spacecraft for a \u201cskip reentry\u201d \u2014 the capsule acts like a flat stone skipping atop the surface of a still lake as it dips briefly into the atmosphere and briefly raises its altitude once more before final descent. The special trajectory allows Orion to target a precise splashdown location.<\/p>\n
In 2024, NASA\u00a0twice\u00a0opted\u00a0to delay the timeline for the Artemis II launch in part to allow more time to collect data.<\/p>\n
The problem, NASA concluded after months of research, was that the Avcoat material used in the Artemis I heat shield was not permeable enough. That meant that when the Orion capsule dipped into the atmosphere, gases built up in the heat shield\u2019s interior, causing chunks of the material to break off and cracks to form.<\/p>\n
None of the experts interviewed by CNN dispute this characterization of why the Artemis I heat shield did not perform as expected.<\/p>\n
Up for debate is how well NASA\u2019s Artemis mission managers understand the problem and exactly how much risk the suboptimal heat shield poses to the four astronauts slated to launch in a few weeks.<\/p>\n
In September, some of the space agency\u2019s Artemis program leaders said they believed Orion\u2019s heat shield would perform well on Artemis II, despite there being no substantial changes to its design.<\/p>\n
In fact, while NASA now plans to manufacture future heat shields to be permeable, Artemis II\u2019s heat shield is actually less permeable than the one built for Artemis I.<\/p>\n
About 6% of the Artemis I heat shield\u2019s surface area was permeable, Olivas noted, and that permeable area did not suffer any cracking. But the Artemis II heat shield, he added, does not have any permeable areas, noting that change was made prior to the Artemis I test flight and before NASA realized the heat shield needed to be permeable to perform well.<\/p>\n
Rick Henfling, the Artemis flight director leading reentry, said during a September news conference that the Artemis II reentry trajectory has been modified with the goal of avoiding the conditions that caused the Artemis I heat shield to crack.<\/p>\n
\u201cWe won\u2019t go as high on that skip, it\u2019ll just be a loft,\u201d Henfling said.<\/p>\n
This new reentry path, Henfling said, should allow the Avcoat material to erode normally.<\/p>\n
\u201cWe want to emphasize that safety is our top priority,\u201d Hawkins added, repeating a long-held NASA mantra.<\/p>\n
The decision to use an altered trajectory was made after extensive testing, NASA said in its Friday statement. And the adjusted return path is designed to create \u201ca steeper descent angle to reduce exposure time at peak heating, thus minimizing further char loss.\u201d<\/p>\n
\u201cThis thorough testing, analysis, simulation, and expert validation collectively formed NASA\u2019s official flight rationale providing sufficient justification to proceed without redesigning the heat shield,\u201d the statement reads.<\/p>\n
Other experts, however, disagree that changing Orion\u2019s flight path is enough to guarantee that the crew will make it home safely.<\/p>\n
\u201cThe reason this is such a big deal is that when the heat shield is spalling \u2014 or you have big chunks coming off \u2014 even if the vehicle isn\u2019t destroyed, you\u2019re right at the point of incipient failure now,\u201d said Dr. Dan Rasky, an expert on advanced entry systems and thermal protection materials who worked at NASA for more than 30 years.<\/p>\n
\u201cIt\u2019s like you\u2019re at the edge of the cliff on a foggy day,\u201d Rasky said.<\/p>\n
Rasky, like Camarda, does not believe that NASA should allow astronauts to fly on board the Artemis II Orion capsule.<\/p>\n
\u2018Yes, it\u2019s going to crack\u2019<\/h3>\n Even some experts who believe Artemis II is safe to fly acknowledge that the Orion heat shield will likely crack and display signs of damage upon its return from Earth, even with the modified trajectory.<\/p>\n
\u201cWill the heat shield crack? Yes, it\u2019s going to crack,\u201d Olivas, the astronaut who aided NASA\u2019s heat shield investigation, said.<\/p>\n
But Orion has some built-in \u201crobustness,\u201d said Dr. Steve Scotti, a distinguished research associate at NASA\u2019s Langley Research Center in Hampton, Virginia, who served as a volunteer on an\u00a0advisory team\u00a0that was involved in the Artemis I heat shield investigation.<\/p>\n
Underneath the Avcoat layer, Scotti said, lies a composite structure that during testing has been able to briefly survive the extreme temperatures of reentry. And that structure could serve as a last line of defense in the unlikely case that the Avcoat material becomes so deformed it begins to expose the underside of the spacecraft, Scotti said.<\/p>\n
The composite structure wasn\u2019t put there as a fail-safe or backup for the heat shield \u2014 but it\u2019s lucky it is there, Scotti said.<\/p>\n
Olivas emphasized that NASA isn\u2019t expecting to rely on the composite structure to keep the astronauts safe. The Avcoat material should still do that, he said. But the structure does provide an extra layer of safety, Olivas noted.<\/p>\n
And even if the Artemis II heat shield performs worse than it did during Artemis I, Olivas and Scotti are confident the astronauts will remain safe.<\/p>\n
\u201cI don\u2019t have any strong fears that the crew is in danger,\u201d Scotti told CNN, echoing Olivas\u2019 sentiments.<\/p>\n
But neither Scotti\u2019s nor Olivas\u2019 expressions of optimism come without an asterisk. Both experts acknowledge, as Camarda argues, that engineers cannot possibly predict exactly how the heat shield will behave.<\/p>\n
\u201cThere\u2019s very little data to be able to put into an analysis\u201d of the heat shield, Scotti told CNN. \u201cThe material itself changes every 20 seconds or so during reentry,\u201d he said, referring to the Avcoat layer.<\/p>\n
\u201cWe still have things we don\u2019t know,\u201d Scotti added. \u201cIt\u2019s not low risk, it\u2019s a moderate risk.\u201d<\/p>\n
\u2018Things we can never know\u2019<\/h3>\n Scotti\u2019s and Olivas\u2019 votes of confidence in the Artemis II mission were hard won.<\/p>\n
Olivas, in fact, held serious doubts about NASA\u2019s intention to fly the Artemis II mission with crew until he sat through a three-hour meeting at the space agency\u2019s headquarters in Washington, DC, on January 8.<\/p>\n
CNN requested and was denied access to the meeting. Only two journalists were invited to attend, and the meeting was expected to be largely off the record because confidential information was being discussed.<\/p>\n
NASA\u2019s newly installed administrator, Jared Isaacman, convened the meeting to gauge dissenting opinions, he told CNN affiliate station\u00a0WESH\u00a0in Orlando.<\/p>\n
The meeting, Isaacman said, \u201conly reaffirmed my confidence in the decisions of the bright engineers at NASA.\u201d<\/p>\n
\u201cWe have modified our reentry profile. We have regained margin to safety, and I feel very good about that with Artemis II,\u201d he added.<\/p>\n\n<\/div>
\nThe flags of the United States and Canada are seen on the left shoulder of the Orion Crew Survival System suits on January 17 at Kennedy Space Center. – Joel Kowsky\/NASA<\/div>\n<\/figcaption><\/figure>\n
But Olivas said his hesitations were absolved by a presentation from a \u201cTiger Team\u201d \u2014 a NASA term for a specialized team brought together to solve a complex problem \u2014 at Johnson Space Center in Houston.<\/p>\n
\u201cThe key parameter here is: When is the heat shield going to crack? And how deep into the atmosphere are you going to be if it does crack?\u201d Olivas said.<\/p>\n
\u201cThere\u2019s things that we can never know until it actually happens,\u201d he added, referring to the heat shield. But the Tiger Team\u2019s analysis gave him confidence that NASA understood the Avcoat material well enough to be certain the crew would not be in danger.<\/p>\n
\u201cThe Tiger Team did a phenomenal job,\u201d Olivas said. \u201cI trust those engineers emphatically, and the program managers who are driving them.\u201d<\/p>\n
That, however, is where Camarda \u2014 who also attended the January 8 meeting at NASA headquarters \u2014 disagrees.<\/p>\n
Fighting with physics<\/h3>\n Camarda takes issue, for example, with a computer program that the Tiger Team used in its heat shield analysis.<\/p>\n
Called the Crack Indication Tool, or CIT, it was meant to model how and when the Avcoat material might begin fragmenting in various conditions.<\/p>\n
What if Orion were to take a smaller \u201cskip\u201d before making its final plunge?<\/p>\n
The CIT is meant to churn out data about how such changes might impact the heat shield \u2014 and whether those scenarios would trigger cracking.<\/p>\n
But the data is imperfect, Camarda argues, and the tool relies on \u201csimplifying assumptions.\u201d<\/p>\n
\u201cThe analysis is a simplistic model to predict gas generation, material charring and qualitatively when cracks happen,\u201d Camarda said. \u201cBut the failure mechanism is how the cracks grow, and it definitely can\u2019t predict that. It cannot predict the stresses and strains that cause the cracks or how they can grow.\u201d<\/p>\n
When asked about Camarda\u2019s criticisms of the CIT, Olivas acknowledged that no computer modeling program is completely accurate. And the CIT cannot predict crack growth.<\/p>\n
But among the data points that assuaged Olivas\u2019 concerns, he said, was the fact that the Tiger Team lined up the computer program\u2019s predictions with real-world lab tests involving Avcoat material. The CIT was also able to correctly predict and re-create the conditions that led to the cracking on Artemis I.<\/p>\n
\u201cThat gave me a confidence that the tool itself was indeed a good predictor,\u201d Olivas said.<\/p>\n\n<\/div>
\nOn the fifth day of the Artemis I mission, a camera on the tip of one of Orion\u2019s solar arrays captures the spacecraft with the moon beyond in November 2022. – NASA<\/div>\n<\/figcaption><\/figure>\n
But, Camarda counters, it is possible to create modeling tools that take a more interdisciplinary approach.<\/p>\n
\u201cA multi-physics analysis can do everything in one computer code,\u201d Camarda said. \u201cIt\u2019s predicting the aero thermodynamic heating on the outside of the vehicle, and studying how the material changes phases and starts to burn and produces gases.\u201d<\/p>\n
That, he said, is the type of analysis that could give program managers a more holistic understanding of the risks this heat shield poses.<\/p>\n
Assessing risk<\/h3>\n To Camarda, the heat shield problem is one symptom of a widespread ailment plaguing NASA that took root in the shuttle era. His view of the agency is informed by his experience as a young astronaut preparing to fly when the Space Shuttle Columbia broke apart during reentry in 2003, killing all seven passengers.<\/p>\n
It marked the second tragedy for the program after the Space Shuttle Challenger was destroyed during ascent in 1986.<\/p>\n
In a phone interview with CNN, Camarda highlighted that in the early 1980s, NASA had estimated that the space shuttle would have a roughly\u00a01 in 100,000\u00a0chance of experiencing a deadly malfunction.<\/p>\n
Ultimately, however, the shuttle flew a total of 135 missions with two explosions, resulting in 14 total casualties. That put the vehicle\u2019s actual odds of experiencing a catastrophic failure at 1 in 67.5.<\/p>\n
At one point during his NASA career, Camarda was appointed head of engineering at Johnson Space Center only, he said, to be pushed out from that role after vocally expressing concerns about mission safety in the aftermath of the Columbia disaster, he wrote in \u201cMission Out of Control,\u201d a memoir and technical deep dive about his years at the agency.<\/p>\n\n<\/div>
\nThe American flag is lowered to half staff at the press site with launchpad 39A in the background, at Kennedy Space Center on February 1, 2003, following the Space Shuttle Columbia disaster. – Duffin McGee\/Reuters<\/div>\n<\/figcaption><\/figure>\n
Camarda\u2019s former boss did not respond to an email request for comment.<\/p>\n
Camarda ultimately left NASA in 2019 after 45 years of service.<\/p>\n
In his view, the space agency has shifted away from a research and discovery mindset that it embodied during the Apollo era \u2014 when engineers were encouraged to identify and express concerns about potential safety issues as they picked apart engineering challenges on a fundamental level.<\/p>\n
In today\u2019s climate, Camarda said, he worries NASA employees are encouraged to fall in line with the assessments and goals of the agency\u2019s management and leadership.<\/p>\n
Edgar Zapata, a retired Kennedy Space Center engineer who still serves on the NASA Innovative Advanced Concepts (NIAC) External Council, a program that aims to fund bleeding-edge technology development, said he shares Camarda\u2019s concerns.<\/p>\n
\u201cI think our experiences are shaded by having seen that once this body politic decides, almost by mysterious forces, that it\u2019s going to do something \u2014 it tends to figure out a way to move forward,\u201d Zapata said of NASA\u2019s decision-making process and risk assessments.<\/p>\n
NASA spokespeople did not respond to a request for comment about criticisms from Camarda regarding the agency\u2019s culture. NASA has long maintained and emphasized that it considers safety to be its top priority.<\/p>\n
\u2018Our history is not perfect\u2019<\/h3>\n Camarda also emphasized that his opposition to Artemis II isn\u2019t driven by a belief it will end with a catastrophic failure. He thinks it\u2019s likely the mission will return home safely.<\/p>\n
More than anything, Camarda told CNN, he fears that a safe flight for Artemis II will serve as validation for NASA leadership that its decision-making processes are sound. And that\u2019s bound to lull the agency into a false sense of security, Camarda warned.<\/p>\n
The two former astronauts and heat shield experts \u2014 Olivas and Camarda \u2014 do not share the same opinion about whether NASA should launch the Artemis II mission with crew on board. But on this point, they agree: \u201cSometimes we get lucky. And when we get lucky, sometimes we trade that for being good \u2014 and then we convince ourselves we\u2019re better than we really are,\u201d Olivas told CNN.<\/p>\n
\u201cI think it\u2019s valid to question what\u2019s happening at NASA,\u201d Olivas added, \u201cbecause our history is not perfect.\u201d<\/p>\n
EDITOR\u2019S NOTE:<\/span>\u00a0 This story has been updated with additional information.<\/p>\nFor more CNN news and newsletters create an account at\u00a0CNN.com<\/p>\n","protected":false},"excerpt":{"rendered":"
When four astronauts begin a historic trip around the moon as soon as February 6, they\u2019ll climb aboard<\/p>\n","protected":false},"author":6,"featured_media":2609,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[73,7,48],"tags":[],"class_list":["post-2608","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-nasa","category-news","category-us"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/posts\/2608","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2608"}],"version-history":[{"count":1,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/posts\/2608\/revisions"}],"predecessor-version":[{"id":2610,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/posts\/2608\/revisions\/2610"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=\/wp\/v2\/media\/2609"}],"wp:attachment":[{"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2608"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2608"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.cedritech.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2608"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}