Updates Artemis Program Updates & Discussions

[Urwumpe]

Water hammer, when the liquid slams to a stop when a valve suddenly closes. It can burst piping.

And did so in spaceflight. The N1 was a victim of this.

 

[Urwumpe]

Funny how it sounds when the RCS fire.
Remindes my of the tubing of the central-heating at my home when a valve is closed to quick and causes "a backslash" (if that's the right term)
...and Yes, there is some air-pockets in the system that should not be there (in my central-heating I mean)

"Ist bei Ihnen schon ein Schnüffelstück gesetzt wurden?"

Spoiler: Northern German Regional Humor Warning

In englisch language it just means "Was already an automatic deaerator valve installed in your house?"

ADG Valve

epuis 1984, ADG Conçoit et commercialise des gammes complètes de robinetteries et de raccords pour les secteurs d'activités très diversifiés : industrie, bâtiment, chauffage, irrigation, adduction d'eau ...

www.adgvalve.com

Which here is plainly called "Schnüffelstück" ("Sniffing piece")

 

[barrygolden]

Just watch this and was impressed. 20 launches per mission never work

Really, really good (and fun) video, not kind to the Artemis architecture, and effectively, its management.

The number of launches needed for a single mission...

 

[kuddel]

Water hammer, when the liquid slams to a stop when a valve suddenly closes. It can burst piping.

I knew that term, but that's a bit to violent - so I didn't use that. If it was water-hammer I would be very concerned
I even built a "demonstrator" with plastic pipes once, to demonstrate that effect to youngsters that thought "close the valve as quickly as possible" was a smart idea

 

[GLS]

Reality slowly converging on what this video mentioned...

https://twitter.com/i/web/status/1744792823851856091

 

[Thunder Chicken]

The Inspector General report on Artemis I was far from good:

https://oig.nasa.gov/wp-content/uploads/2024/05/ig-24-011.pdf

Summarized here:

MSN

The heat shield damage (Fig. 3 in the report):

Melted capsule / service module separation bolt (Fig. 4)

From the report:

Separation bolt melt beyond the thermal barrier during reentry can expose the vehicle to hot gas ingestion behind the heat shield, exceeding Orion’s structural limits and resulting in the breakup of the vehicle and loss of crew. Post-flight inspections determined there was a discrepancy in the thermal model used to predict the bolts’ performance pre-flight. Current predictions using the correct information suggest the bolt melt exceeds the design capability of Orion.

They really need to do a repeat of Artemis I before they put a crew on this thing. What a mess. It gets worse the more you read.

EDIT: There was also significant damage to the pad launch complex. Post flight repairs were budgeted for $5 million, but actual damage was assessed at $26 million.

 

[Gargantua2024]

So, Orion needs a major redesign of its heat shield before they allow Artemis 2 to fly?

 

[Thunder Chicken]

So, Orion needs a major redesign of its heat shield before they allow Artemis 2 to fly?

They need to understand what happened to this heat shield before they can design another. They currently don't.

They also have hardware-related random power problems due to the radiation environment which basically forces them to reset the panel breakers every time it happens. They don't have a fix for this. Losing power randomly during critical mission events probably is very bad. The systems are supposed to be redundant, but they lose that redundancy when one falls off line, and there is some non-zero probability of losing both at the same time.

Here goes NASA management trying to get a mission to happen without complete understanding of the vehicle and fixing problems by simply hoping that they don't happen because they don't have the budget for anything else. If they don't shut down this program somebody is going to die on this thing.

 

[Gargantua2024]

A Challenger/Columbia waiting to happen

 

[Thunder Chicken]

 

[TheShuttleExperience]

The Inspector General report on Artemis I was far from good:

https://oig.nasa.gov/wp-content/uploads/2024/05/ig-24-011.pdf

Summarized here:

MSN

The heat shield damage (Fig. 3 in the report):

Melted capsule / service module separation bolt (Fig. 4)

From the report:



They really need to do a repeat of Artemis I before they put a crew on this thing. What a mess. It gets worse the more you read.

EDIT: There was also significant damage to the pad launch complex. Post flight repairs were budgeted for $5 million, but actual damage was assessed at $26 million.

Quite a flashback to STS.

The base heat shield looks really bad. I would not yet ride on this vehicle. At least not on a mission returning from deep space.

 

[TheShuttleExperience]

 

[TheShuttleExperience]

I'm not an engineer and I don't have a scientific background. When I consider the time frame Orion has been in development and when I look at that devastating report, I'm curious how the Apollo engineers managed to do this with less experience, less advanced tools and in a shorter period of time. Or was it simply the 10x higher budget that was available back then?

 

[diogom]

Not excusing the necessity of understanding why this happened, but I thought they also had an intentionally harder re-entry than a crew would have? Specifically to push the heatshield and systems.

 

[Thunder Chicken]

I'm not an engineer and I don't have a scientific background. When I consider the time frame Orion has been in development and when I look at that devastating report, I'm curious how the Apollo engineers managed to do this with less experience, less advanced tools and in a shorter period of time. Or was it simply the 10x higher budget that was available back then?

10x budget and engineering that relied much more heavily on physical testing and verification than computational simulation. They flew over a dozen missions on the Saturn IB and two of the full Saturn V stack before flying crews, testing nearly all the systems under flight conditions. That 10X budget really wasn't extravagant as they really had no alternative than to flight test everything back then. Hardware is expensive. And even still, we lost the crew of Apollo 1 and had the Apollo 13 incident.

Even with modern computer modeling and simulation, your results are only as good as your inputs and physics models. Just because a computer spits out an answer doesn't mean it's correct. Apparently there was some parameter in the Artemis thermal modeling that was incorrect and they only discovered that after they had the test flight. Computer modeling is not a substitute for actual test data. But computer simulations are far cheaper, so there is a tendency to lean on those results vs. doing more physical testing. But computer simulations must be validated against test data, otherwise it is nothing more than a best guess.

Not excusing the necessity of understanding why this happened, but I thought they also had an intentionally harder re-entry than a crew would have? Specifically to push the heatshield and systems.

They did a free-return with a low perilune on Artemis I like planned for Artemis II. Unless they actually burned prograde when on return to increase their kinetic energy it should have been a representative test of a nominal Artemis II re-entry.

If they forced it to undergo a reentry say 120% harder than the intended mission reentry and the heat shield came through flawlessly, they could be very confident in that heat shield. But if they proof to 120% and the heat shield picks up all sorts of unexpected damage, what does that tell us? The damage would tell us that there is something that isn't understood about the physics, and the fact that it survived doesn't necessarily mean there is any safety margin - it could just mean that they got damned lucky.

The shuttle experienced lots of debris damage on the TPS for many years and many flights, and NASA management took that as a sign that it was not a safety concern. What they unwittingly did with this decision was play Russian roulette on each flight until a particular piece of foam hit a particular sensitive spot when the Columbia was lost. Doing analysis beforehand costs a lot of money and schedule, but relying on luck costs nothing ... except lives, when the luck invariably runs out.

 

[Gargantua2024]

Apollo had 5 test flights (2 suborbital, 2 HEO, 1 LEO) dedicated in testing its heat shield performance before Apollo 8, while Orion had only EFT-1 doing it before Artemis 1. I think even if Apollo engineers had less experience in terms of actual spaceflight time, they understood more of how Apollo's heatshield work than current engineers do sadly, despite using basically the same technology (could be knowledge lost after almost 60 years being unused)

 

[Thunder Chicken]

What concerns me is that they are struggling with a technical capability that was sorted out during Apollo just to fly a modern mission replicating Apollo 8, even with all our modern engineering technology. Knowledge has been lost or ignored. And the mission architecture envisioned for a human landing and return under Artemis is more complicated than Apollo with more components like Gateway and HLS. Gateway is basically a mini ISS to be put into orbit around the moon, and NASA seems to have forgotten how difficult it was just to get ISS assembled and operational in LEO. The Starship-based HLS is a Heinleinian fantasy at this point and it's not even clear how they are going to keep it all fueled, or land it safely, or get in or out of the damned thing once it is on the surface. It's insane.

Apollo got humans to the moon because the engineers and scientists had a clear objective and they were humbled by the unknowns involved, and so they worked to keep the systems as simple and robust as possible, and they very thoroughly tested the full systems before sending crews on them. Artemis seems to be complexity for complexity's sake, making sure all the contractors get a nice slice of pork. I'm horrified that they actually are going to try to send humans to the Moon in this mess. The managers of the Artemis project need to get humble, and I hope it doesn't take the loss of a crew for them to do so.

 

[GLS]

Apollo had 5 test flights (2 suborbital, 2 HEO, 1 LEO) dedicated in testing its heat shield performance before Apollo 8, while Orion had only EFT-1 doing it before Artemis 1. I think even if Apollo engineers had less experience in terms of actual spaceflight time, they understood more of how Apollo's heatshield work than current engineers do sadly, despite using basically the same technology (could be knowledge lost after almost 60 years being unused)

What concerns me is that they are struggling with a technical capability that was sorted out during Apollo just to fly a modern mission replicating Apollo 8, even with all our modern engineering technology. Knowledge has been lost or ignored.

Specifically on the heatshield, the current design is not what was used in the Apollo CM. Did they change it for reusability? Mass? Safety margin? Ease of manufacturing? All good reasons, but clearly the one test flight in 2014(?) wasn't enough.

The Starship-based HLS is a Heinleinian fantasy at this point and it's not even clear how they are going to keep it all fueled, or land it safely, or get in or out of the damned thing once it is on the surface. It's insane.

IMO, Starship on the Moon makes no sense. I think the landers should have a horizontal design, so that the c.g. is lower and surface access is easier. Also, why use an aerodynamic design with heashield and wings/flaps on the Moon? A single-stage reusable lander, that goes from the surface to a station (in LLO and not the high-orbit non-sense) seems more sustainable.

 

[Gargantua2024]

I'd understood why Gateway is planned to be placed in high lunar orbit than a low one. Less time for communication blackouts by simply going behind the Moon on Earth's perspective, and (pure speculation here) they also want to have crewed landings on the Far Side sometime in the future

 

[GLS]

I'd understood why Gateway is planned to be placed in high lunar orbit than a low one. Less time for communication blackouts by simply going behind the Moon on Earth's perspective, and (pure speculation here) they also want to have crewed landings on the Far Side sometime in the future

Put a couple of relay sats in that orbit instead.