NASA IG: Major technical problems with Orion remain unsolved
Damage to Orion heat shield caused during re-entry,
including “cavities resulting from the loss of large chunks”
A just released report [pdf] by NASA’s inspector general has found the major technical problems discovered after the first unmanned Artemis mission of Orion around the Moon remain unsolved, and threaten the safety of the astronauts that NASA plans to send around the Moon on the second Artemis mission.
The problems with Orion are threefold and are quite serious, involving its heat shield, separation bolts, and power distribution.
Specifically, NASA identified more than 100 locations where ablative thermal protective material from Orion’s heat shield wore away differently than expected during reentry into Earth’s atmosphere. Engineers are concurrently investigating ways to mitigate the char loss by modifying the heat shield’s design or altering Orion’s reentry trajectory.
In addition, post-flight inspections of the Crew Module/Service Module separation bolts revealed unexpected melting and erosion that created a gap leading to increased heating inside the bolt. To mitigate the issue for Artemis II, the Orion Program made minor modifications to the separation bolt design and added additional thermal protective barrier material in the bolt gaps.
NASA also recorded 24 instances of power distribution anomalies in Orion’s Electrical PowerSystem. While NASA has determined that radiation was the root cause and is making software changes and developing operational workarounds for Artemis II, without a permanent hardware fix, there is increased risk that further power distribution anomalies could lead to a loss of redundancy, inadequate power, and potential loss of vehicle propulsion and pressurization.
Moreover, like with any engineering system, without understanding the residual effects of introducing design and operational changes, it will be difficult for the Agency to ensure that the mitigations or hardware changes adopted will effectively reduce the risks to astronaut safety.
This is not all.
[D]uring recent qualification and acceptance testing of Orion’s circuitry and Crew Module batteries, NASA discovered hardware defects that increase crew safety risks. Regarding the circuitry issues, NASA is working to make modifications to hardware in difficult-to-access locations inside the already assembled Orion spacecraft and perform additional tests. The investigation into the battery issues is in the early stages, and NASA has not yet identified a resolution.
The report also found the launch caused five times the damage to the mobile launcher than expected.
Because of these issues NASA in January 2024 delayed the first Artemis manned mission from late 2024 to late 2025. I guarantee that new date won’t happen either. The heat shield damage remains unsolved, with no clear solution in sight. Expect this mission to be delayed into ’26, if not further.
What is most disturbing is that NASA decided — in order to reduce cost and increase safety — to use the same Apollo ablative heat shield designs of the 1960s and 1970s. Yet, modern engineers and technology produced a modern version that can’t do the job safely. Nor have modern engineers and technology explained the failure.
It is unclear why, but it makes using Orion at this point in a manned mission to the Moon a very dangerous proposition.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Damage to Orion heat shield caused during re-entry,
including “cavities resulting from the loss of large chunks”
A just released report [pdf] by NASA’s inspector general has found the major technical problems discovered after the first unmanned Artemis mission of Orion around the Moon remain unsolved, and threaten the safety of the astronauts that NASA plans to send around the Moon on the second Artemis mission.
The problems with Orion are threefold and are quite serious, involving its heat shield, separation bolts, and power distribution.
Specifically, NASA identified more than 100 locations where ablative thermal protective material from Orion’s heat shield wore away differently than expected during reentry into Earth’s atmosphere. Engineers are concurrently investigating ways to mitigate the char loss by modifying the heat shield’s design or altering Orion’s reentry trajectory.
In addition, post-flight inspections of the Crew Module/Service Module separation bolts revealed unexpected melting and erosion that created a gap leading to increased heating inside the bolt. To mitigate the issue for Artemis II, the Orion Program made minor modifications to the separation bolt design and added additional thermal protective barrier material in the bolt gaps.
NASA also recorded 24 instances of power distribution anomalies in Orion’s Electrical PowerSystem. While NASA has determined that radiation was the root cause and is making software changes and developing operational workarounds for Artemis II, without a permanent hardware fix, there is increased risk that further power distribution anomalies could lead to a loss of redundancy, inadequate power, and potential loss of vehicle propulsion and pressurization.
Moreover, like with any engineering system, without understanding the residual effects of introducing design and operational changes, it will be difficult for the Agency to ensure that the mitigations or hardware changes adopted will effectively reduce the risks to astronaut safety.
This is not all.
[D]uring recent qualification and acceptance testing of Orion’s circuitry and Crew Module batteries, NASA discovered hardware defects that increase crew safety risks. Regarding the circuitry issues, NASA is working to make modifications to hardware in difficult-to-access locations inside the already assembled Orion spacecraft and perform additional tests. The investigation into the battery issues is in the early stages, and NASA has not yet identified a resolution.
The report also found the launch caused five times the damage to the mobile launcher than expected.
Because of these issues NASA in January 2024 delayed the first Artemis manned mission from late 2024 to late 2025. I guarantee that new date won’t happen either. The heat shield damage remains unsolved, with no clear solution in sight. Expect this mission to be delayed into ’26, if not further.
What is most disturbing is that NASA decided — in order to reduce cost and increase safety — to use the same Apollo ablative heat shield designs of the 1960s and 1970s. Yet, modern engineers and technology produced a modern version that can’t do the job safely. Nor have modern engineers and technology explained the failure.
It is unclear why, but it makes using Orion at this point in a manned mission to the Moon a very dangerous proposition.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
It may be that DEI astronauts are the only folks who would agree to ride this rocket.
“What is most disturbing is that NASA decided — in order to reduce cost and increase safety — to use the same Apollo ablative heat shield designs of the 1960s and 1970s. Yet, modern engineers and technology produced a modern version that can’t do the job safely. Nor have modern engineers and technology explained the failure.”
I don’t quite understand this. It seems the first sentence says they reused an old design, but the next seems to say they used a “modern version”. Can you clarify, please?
I wonder how much of that heat shield damage is from spalling or shattering when the hot shield parts hit the cold water? They call them cavities in the photo.
I am sure they have infra red heat images of the craft coming down that should give them a better idea of how hot the shield was just before it hit the water.
You would have thought that they would have gone with the pretty well proven shuttle tile system.
If they did go with the shuttle tiles then i would say they placed them to close together and when they expanded in the heat they broke each other by pressure and vibration.
Ray, I assume it means that they used the old design but couldn’t manufacture materials to the same specs. The report refers to a material called “Avcoat”, which was used in Apollo, however:
from https://en.wikipedia.org/wiki/AVCOAT
“The Avcoat to be used on Orion is reformulated to meet environmental legislation that has been passed since the end of Apollo
Ray Van Dune: Andi more or less answers you question. The original plan for Orion’s heat shield was to go with an entirely new concept. NASA found however that it took too long, and cost too much. In 2014 they switched back to the ablative system used by Apollo. This still involved some changes, partly because of the larger size of the shield for Orion, and partly because NASA wished to take advantage of modern computer technology in building the shield.
Ray,
NASA did both – sort of.
The original Orion heat shield was a one-piece unit as were the heat shields for Apollo. But the Avcoat material used was only an approximation of the Avcoat formulation used back in the Apollo days. Several of the original Avcoat’s ingredient chemicals were no longer available any longer owing the their toxicity and limited other uses. EPA and OSHA regulations had, over the years since Apollo, rendered them economically impractical to continue making and using and they had been replaced, for other use cases, with other, more benign chemicals. Avcoat 2.0 was an approximation of the original formula and not the Avcoat of Apollo, but it was considered by NASA to be close enough for government work.
The original Orion heat shield was also fabricated using the same labor-intensive techniques as those of the Apollos – with human beings using caulking guns to individually fill each of thousands of cells in the heat shield framework with Avcoat. As had also proven the case with the original Apollo heat shields, the Orion shield required a lot of rework to re-do cells that proved to have voids of various sizes in the Avcoat after it was cured.
The expense of this process was probably viewed by LockMart as a positive given that Orion was being built on a cost-plus basis. But it was apparently also the case that the heat shields – being rather larger than the original Apollo items – would simply take too long to make and would adversely affect the overall program schedule.
NASA still flew the original monolithic Avcoat heat shield on the boilerplate version of Orion that was test launched on a Delta IV Heavy back in 2014, but the decision had apparently already been made to re-engineer the whole shield. The new version – which is what flew on the Artemis 1 mission – is a segmented design constructed of blocks of cast Avcoat that were machined to final size after curing. The general approach turned out to be quite reminiscent of how SpaceX fabricates the PICA-X heatshields for Dragons.
If your doing all that work for an ablative shield they might as well just went whole hog and used the shuttle tiles and system.
If the whole heat shield comes off as one piece then it would be easy to unbolt and replace each tile at the end of each mission. Unlike on the shuttle they actually had to chip them off and then replace them.
I do not have access to the data on either material.
Do the ceramic tiles as used on the shuttle have a weight penalty, compared to the modernized AVCOAT
sippin_bourbon:
AVCOAT 32lb/ft^3 (https://en.wikipedia.org/wiki/AVCOAT)
Shuttle tile Black 9 – 22 lb/ft^3 White 9 – 12 lb/ft^3 (https://www.nasa.gov/wp-content/uploads/2023/06/shuttle-tiles-9-12v2.pdf) Pg 3.
Some comments:
1. The angle of the view makes it difficult to be sure, but from the “before” picture of the Orion heat shield, it appears there may be instances of continuous aligned seams near the attachment bolts that exhibited greater than expected erosion. The avoidance of such seam alignment was a design feature of the SpaceX hexagonal tile design.
2. The (notorious in some quarters) Aerospace Safety Advisory Panel (ASAP) does not seem to be mentioned in the report, which is authored by the OIG, or Office of Inspector General. In the conclusion of the report there is an acknowledgment of questions of whether the OIG was becoming involved in “engineering” recommendations. Is there a possible role overlap or lack of role clarity?
3. The Apollo capsule used a “skipping” trajectory on return to the atmosphere to mitigate exposure to atmospheric entry heating (also for course correction). Is this being used (or could it be) for Orion?
Dick Eagleson wrote: “NASA still flew the original monolithic Avcoat heat shield on the boilerplate version of Orion that was test launched on a Delta IV Heavy back in 2014, but the decision had apparently already been made to re-engineer the whole shield.”
This is correct. I recall that Robert had complained at the time that flying the heat shield that would not be used, back in 2014, didn’t give useful information and was a waste of a test mission. He was proved correct. Had they waited until the new heat shield was available (slipping a milestone payment to Lockheed Martin), then they could have discovered this problem several years ago and probably would have had time to solve the problem and flown a good heat shield on Artemis I.
The milestone payment was made in a timely manner, but the information needed was not found in such a timely manner.
Edward and Dick Eagleson: See this post from December 2014:
Orion launch on Thursday given go-ahead
“The Apollo capsule used a “skipping” trajectory on return to the atmosphere to mitigate exposure to atmospheric entry heating (also for course correction). Is this being used (or could it be) for Orion?”
Yes, skipping is being used. I can’t get excited about Artemis. It seems mainly to be designed to waste money. The useful function is to actually demonstrate to the world how hopeless any government effort is. Pity it is so expensive to do that.
As an aside, it is not only at NASA and its contractors that hard won skills and technologies are being lost. https://threadreaderapp.com/thread/1785649451702337543.html
One of the things that happens when you outsource the ability to make most of the things that you consume is that you also lose the cultural infrastructure — from shop classes to local machine shops — that supports such endeavors. And, when it’s gone, it’s hard to get it back. Oh, well. According to the World Economic Forum, we aren’t supposed to have automobiles or much of anything else in the future anyway.
I would have taken the weight penalty in exchange to the ease of replacement and the known functionality of the tile system.
But this is NASA and they will spend a billion to save a few pounds thinking that in the long run it gets them a better return.
That billion could have been used to fund another launch instead.
It seems to have always broken in from an edge. Almost looks like a ‘popcorning’ effect.
To Milt–you are very right.
If you are not using you’re losing
I consider what is going on part of regaining old know-how—something not done by killing programs
pzatchok wrote: “I wonder how much of that heat shield damage is from spalling or shattering when the hot shield parts hit the cold water?”
A good question, but it seems that such behavior is still outside the expectation of the engineers. In order to ensure crew safety, the engineers must understand how the materials, the configuration, and the construction work, otherwise it is all guesswork. If this is happening, then they need to know, and they need to know why it happens.
“If your doing all that work for an ablative shield they might as well just went whole hog and used the shuttle tiles and system.”
The Shuttle’s tile are not ablative. To use non-ablative heat shielding, the reentry vehicle needs to stay higher in the atmosphere for a longer time, so it needs to be more of a lifting body and less of a capsule. See the graph in the following link:
https://www.researchgate.net/figure/Earth-Re-entry-paths-as-Velocity-altitude-graphs-showing-the-influence-of-the_fig4_261316575
For non-ablative, reusable heat shields (thermal protection system, or TPS), the vehicle must stay above the thick black line. If the vehicle goes below that line, then ablation is needed to take away the excessive heat. An ablative heat shield melts, and the hot melted material (full of heat energy) is swept away from the vehicle by the wind, carrying away quite a bit of energy, as the kinetic energy of the motion of the spacecraft is turned into heat energy as the vehicle slows down.
I noticed that the reentry line for Apollo does not rise, as I would expect for a skipping reentry trajectory, but the green line for Mars return trajectory does. Also, note that there is no time axis, only speed and altitude. So I went on a search for a previously asked question about an Apollo skip reentry:
https://space.stackexchange.com/questions/49546/did-the-apollo-command-module-really-skip-within-or-off-of-the-atmosphere-as
One of the answers contained this:
Another answer in that link presented a chart that shows Apollo rising several thousand feet during reentry, so perhaps what we have been thinking of as a skip trajectory is not quite a skip trajectory.
From a second search, here is what someone said about the skip maneuver:
https://space.stackexchange.com/questions/3068/how-does-skipping-off-the-atmosphere-work
Of course, I am finding relatively random answers from people whose pedigrees we don’t know, so these should be taken with a grain of salt.
Wikipedia, which may be more reliable (please don’t laugh that hard), says this:
https://en.wikipedia.org/wiki/Non-ballistic_atmospheric_entry
Also note that these answers tend to suggest that there is an “out of the atmosphere,” which really only means that somewhere in the answer there is an arbitrarily assumed “edge” to the atmosphere.
Since SpaceX has obviously mastered heat shield technology for space capsules returning to Earth (I’m not talking about Starship) how about SpaceX offering to share their technology for……say…….20-40 launch licenses with absolutely NO strings attached. Since the FAA has no ability or desire to really independently review SpaceX (as Robert states, they just retype the internal SpaceX review, and take their sweet time about it), SpaceX will investigate, report, and fix any issues.
But what if you didn’t “need” a heat shield?
Here is a bit of forgotten history from the First Space Age:
https://getpocket.com/explore/item/chrysler-s-radical-space-shuttle-design-was-50-years-ahead-of-its-time
After watching this amazing video, all I can think of is the Roadrunner (as adopted by Chrysler for one of its cars) saying “Meep, Meep!”
to Boeing, lol.
https://www.youtube.com/watch?v=Hd2JgADY9d8
Nasa said that on a return from the moon the capsule is moving 40% faster than any capsule coming in from low Earth orbit like the ISS.
So yes I can see the differences. But….
They have to make a few choices at this point. All about how they might slow down the craft or improving the heat shield far beyond what they are doing now.
How could they slow down the craft?
Aerobraking could be done better and for longer. Somehow either bounce into and out of the atmosphere for a longer time.
Or maybe place three of 4 winglets on the sides of the capsule that would fold out and show more surface area and help fly the craft(give it better lift).
Or they could just slap more shield material on and let it crush its way through the air the way it is now.
Or slow it down before or even after it gets into an Earth orbit. Come into a higher Earth obit and while there use fuel and the motors already on it to slow it down.
More than likely Nasa will just crush it through the atmosphere like they are now and try to improve the shield.