Great Debrief Philip . . . It was really good to see the recording of re-entry and see how the forensics of the event unfolded, capturing the heatshield loss. It took me back to Columbia with recurring images embedded in my memory of that terrible day. As always, your reports are greatly appreciated. Thanks again 😊
Thank you! What about the - visible but not glowing - pieces of unknown material, flying away in the early phase of re-entry? Is this some shrink-foil to protect the capsule from humidity while waiting for liftoff outside the construction facility, or something else? Especially some seconds before 5:00.
@RghHgr The upper portion of the capsule has a layer of foil-like TPS (for solar heating, not reentry heating) that will largely burn off during re-entry. This is expected, and there are Shuttle-derived tiles underneath.
What is your perspective on adopting an Apollo-type reentry profile as an alternative to a skip reentry? This approach reduces the risk of heat shield loss; however, I would like to understand the implications of the increased G-forces on astronaut safety.
While I can't speak for Philip, I personally would say that the Apollo experience shows the crew risk to be minimal. Having a gentler re-entry is certainly more desirable, but I don't think the lack of one represents a safety risk.
I don't think the skip reentry is for crew comfort; Apollo was not a particularly rough ride as far as capsules go. I think the skip reentry is to allow the ship to reach the splashdown area from a wider variety of inbound trajectories. Going with an Apollo style reentry limits the choices for which way to approach the earth or what time of day to plan the return.
Can any of the defects be traced to how the Avcoat was installed vs. Apollo? I understand the heat shield was installed in sections on Orion vs. homogeneous on Apollo.
Apollo's heatshield wasn't homogenous, it used a honeycomb like structure which was super labor intensive (and expensive) to manufacture. And just google about "Apollo 16 heatshield". It was waaaaaay worse than Artemis I. And it was literally mentioned _several_ times in the video that the problem was the skip-reentry profile. During the "slowdown" phase the shield became already hot and Inside the heatshield gases heaten up and expanded which lead to cracks and liberated some pieces from the heatshield when the actual reentry happened. And most importantly: the heatshield worked perfectly, NASA just wanted to know and understand why this happened.
@@saxusNot just the honeycomb substructure itself was a pain, each hole of it had to be manually filled with phenolic epoxy resin and it had to be done extremely meticulously with no air bubbles trapped inside. Highly skilled manual labor was one of the crucial and most intricate parts of the program.
As far as I can tell all of these issues with the new heatshield can be avoided by simply using the old design. The new design is not needed because the primary advantage of the new heatshield design (time to manufacture) is simply irrelevant given the current and projected Artemis schedule.
It's not just a production time concern: It's a manufacturability concern. The Orion heat shield is significantly larger than its Apollo counterpart. It is physically quite difficult to manufacture a single, monolithic part to the required standard of safety - not _just_ slow, costly, and time-consuming. Splitting it made sense, even if it had unintended consequences.
Love your stuff - I feel like this is your best work yet.
Great Debrief Philip . . .
It was really good to see the recording of re-entry and see how the forensics of the event unfolded, capturing the heatshield loss. It took me back to Columbia with recurring images embedded in my memory of that terrible day.
As always, your reports are greatly appreciated. Thanks again 😊
the legend returns with some mid week content! thank you, sir!
fantastic job at removing the echo from Amit's press conference segments!!!!!!
Great report. Wonder how they correlated a specific char libration event to an exact location on the heat shield.
Great video, love it.
Thank you! What about the - visible but not glowing - pieces of unknown material, flying away in the early phase of re-entry? Is this some shrink-foil to protect the capsule from humidity while waiting for liftoff outside the construction facility, or something else? Especially some seconds before 5:00.
@RghHgr The upper portion of the capsule has a layer of foil-like TPS (for solar heating, not reentry heating) that will largely burn off during re-entry. This is expected, and there are Shuttle-derived tiles underneath.
Great video Phillip
If the root cause was that permeability was not uniform, is there understanding - in terms of heat shield production - of why this was so?
Another great video. Thank you!🚀🛰🌑
Thanks Phillip!
Philp, is this type of skip reentry they plan to use on Artemis II🤔…
No, they are skipping the skip, so to speak, for this one time only. It'll be a lot more like the Apollo re-entries from the Moon.
@ it’s a shame that the Apollo heatshield process used on EFT-1 was too time & $ consuming for Orion.
@@PhilipSloss Apollo did use the skip-entry profile. It was tested on both Apollo 4 and 6: ruclips.net/video/KTqe7lz7aEM/видео.html
What is your perspective on adopting an Apollo-type reentry profile as an alternative to a skip reentry? This approach reduces the risk of heat shield loss; however, I would like to understand the implications of the increased G-forces on astronaut safety.
While I can't speak for Philip, I personally would say that the Apollo experience shows the crew risk to be minimal. Having a gentler re-entry is certainly more desirable, but I don't think the lack of one represents a safety risk.
I don't think the skip reentry is for crew comfort; Apollo was not a particularly rough ride as far as capsules go. I think the skip reentry is to allow the ship to reach the splashdown area from a wider variety of inbound trajectories. Going with an Apollo style reentry limits the choices for which way to approach the earth or what time of day to plan the return.
@@RCAvhstape@RCAvhstape Excellent response, I wish everyone answered the comments as well as you.
Can any of the defects be traced to how the Avcoat was installed vs. Apollo? I understand the heat shield was installed in sections on Orion vs. homogeneous on Apollo.
Apollo's heatshield wasn't homogenous, it used a honeycomb like structure which was super labor intensive (and expensive) to manufacture. And just google about "Apollo 16 heatshield". It was waaaaaay worse than Artemis I.
And it was literally mentioned _several_ times in the video that the problem was the skip-reentry profile. During the "slowdown" phase the shield became already hot and Inside the heatshield gases heaten up and expanded which lead to cracks and liberated some pieces from the heatshield when the actual reentry happened.
And most importantly: the heatshield worked perfectly, NASA just wanted to know and understand why this happened.
@@saxus I don't think chunks missing from a TPS counts as 'worked perfectly'.
@@IamZim11 It worked as intended because there was still plenty of margin left, it just didn't behave exactly as expected.
@@saxusNot just the honeycomb substructure itself was a pain, each hole of it had to be manually filled with phenolic epoxy resin and it had to be done extremely meticulously with no air bubbles trapped inside. Highly skilled manual labor was one of the crucial and most intricate parts of the program.
@ I'm picking on the 'perfectly' part of his post, it obviously worked but by no means it was a good result even if it was within tolerances.
As far as I can tell all of these issues with the new heatshield can be avoided by simply using the old design. The new design is not needed because the primary advantage of the new heatshield design (time to manufacture) is simply irrelevant given the current and projected Artemis schedule.
It's not just a production time concern: It's a manufacturability concern. The Orion heat shield is significantly larger than its Apollo counterpart. It is physically quite difficult to manufacture a single, monolithic part to the required standard of safety - not _just_ slow, costly, and time-consuming. Splitting it made sense, even if it had unintended consequences.
@TheBleggh That's fair, and it sounds like they have a solution either way.
@@TheBleggh Almost as if all of this was already explained in the conference...
investigated this