USAF: Orion Crew Will Not Survive Early Mission Abort.

[exoscientist]

Just saw this being discussed on another forum:

July 17, 2009.
USAF: Orion Crew Will Not Survive Early Mission Abort.
http://www.nasawatch.com/archives/2009/ ... _crew.html

USAF 45th Space Wing Study: Capsule~100%-Fratricide Environments (Implications for NASA's Ares-1 and Crew).
STATUS REPORT
Date Released: Thursday, July 16, 2009
http://www.spaceref.com/news/viewsr.html?pid=31792


Bob Clark

 

[mr_mark]

Ok lets, face it, these reports are biased and probably written by airforce contractors who would rather see the Orion capsule fly on one of their launchers. Did you not think that Nasa has not thought of this when they designed Ares 1? Please! Alot of thinking goes into the building of rockets. You could say the same thing about any space vehicle, if it blows up you probably will not survive. Hey, if you are driving in your car and the fuel tank blows you probably won't survive, if you are flying in a plane and a stactic charge ignites the fuel tank you won't survive either. This is how it is when you take the ride, you can never be sure. You walk across the street and you could get hit by a car. It's really all an odds game. An escape system can only increase the odds of survival, not guarantee them.

 

[scottb50]

An escape system can only increase the odds of survival, not guarantee them.

Well, that's what statistics are all about, there is a number for any outcome, foreseen or out of the blue. If it can happen then it very well might or very well might not, basically the same odds.

The Apollo, or ARES system probably offers, or offered, the best chance of escape from a vertically staged vehicle, that it offers 100% safety involves too many variables.

A TSTO vehicle could offer even better odds, but again 100% is unattainable,you could slip in the shower tomorrow, there's a number for that also.

With a TSTO vehicle an upper stage could boost the crew Module independently to a survivable altitude, or away from a failing first stage once airborne, greatly increasing the odds of survival. That would be much better, but again it couldn't be made fool-proof.

Launching a 747 from the end of a runway with maximum fuel at maximum weight also assumes a lot of risk, a lot can be foreseen and dealt with but not everything.

 

[radarredux]

The danger seems to be the super hot debris from the SRB destroying the parachute system (and possibly capsule). Some of the variants to Constellation architecture (the Ares IV (stumpy) and the renewed interest in the Shuttle-C (I've been away too long, forgot the names)) also include the SRBs, so wouldn't they have the same issue?

It seems to me that this analysis, if accepted, is a threat to more than just the Ares I. Virtually all manned launches using solid rocket motors would have similar risks.

 

[radarredux]

Ok lets, face it, these reports are biased and probably written by airforce contractors who would rather see the Orion capsule fly on one of their launchers.

That is a pretty strong statement. Disagreements with their conclusions should probably be based on looking at their analysis approach and pointing out flawed assumption, limited data points, etc.

Did you not think that Nasa has not thought of this when they designed Ares 1?

From one of the articles: [Jeff Hanley] "said NASA had done its own study, using supercomputers to replicate the behavior of Ares I, that predicted a safe outcome."

This would be a good place to pick up on the analysis. NASA could run its supercomputer models on the Titan IV and see if they come up with the same results that actually happened with the Titan IV. If NASA's supercomputer models comes up with the same results as the Titan IV, it would lend credibility to NASA's view that Ares I is safe. If the models come up with something different, it would raise questions to NASA's supercomputer models. In any case, it seems like a good starting point.

You could say the same thing about any space vehicle, if it blows up you probably will not survive.

I think the primary issue is the different profiles between a liquid fueled rocket being destroyed and a solid fueled rocket being destroyed. From the evidence I've heard, the crew of the Challenger did in fact survive the destruction of the liquid fueled portion of their rocket (the SRB's were not destroyed), but they had no parachute system for the crew cabin. If, say (to throw out numbers pulled out of the air) survival from the destruction of a solid fuel rocket is 10% and survival of a liquid fueled rocket is 30%, I think a lot of consideration should be given to this difference.

 

[mr_mark]

ok, I say the darn thing flies(lol). My family has been in aviation since it's very beginnings. In fact I'm pretty much the only member who isn't. My grandfather helped the army aircore in world war 2 as a civilian contractor before going on to work for the company that supplied chemical lubricants and outer coatings to aircraft such as the stealth fighter and bomber. Also my great uncle was one of the mechanics for the spirit of st.louis and was there during it's intial trials in san diego. He later went on to help design the landing gear assemblies for the p38 lightning and the p51 mustang. After that he worked for Eastern airlines. So flight runs in my blood, so I say let ares fly. If the thing has wings we'll soon find out. I have a hunch that everything will turn out ok. Like all designs it needs some tinkering. I remember my great uncle saying that fully loaded they were not even sure if the spirit of st.louis would get off the ground. History showed a different result.

 

[steve82]

The report seems to use "abort" synonymously with "destruct". An Abort is an early mission termination for any reason, not necessarily a booster explosion. The geometry of the Ares vehicle is also not taken into consideration-the Orion CM is atop the Orion SM which is atop the Ares liquid 2nd stage which is atop the solid fueled first stage, putting it quite a ways away from the center of the assumed explosion that will likely have most of its debris heading radially outward and not upward through the 2nd stage/SM structure. They also don't take into consideration how the LAS abort sequence works and how late the various parachutes deploy or the protection afforded by the Boost Protective Cover assuming the LAS has to power the CM through the debris cloud. This report is getting a lot or attention for the wrong reasons. Instead of being a stepping off point for improving the range safety strategy, it is being waved around as a supposed inadequacy of the Ares vehicle.

 

[gunsandrockets]

Here is a link to a video of a Delta II SRB explosion that puts this abort issue into perspective...

http://www.youtube.com/watch?v=WsVzpE7ltb8

From what I have heard, the early abort scenario for an Ares I has a fallout zone of three miles diameter! If true I can see how an Orion parachute wouldn't survive in such an environment. Maybe this is a false alarm, but it sounds like real trouble for any SRB boosted crew launch vehicle, Ares I or otherwise.

 

[radarredux]

Here is a link to a video of a Delta II SRB explosion that puts this abort issue into perspective...

One (of many) questions I have is the Delta II explosion in the video and the Titan IV used in the analysis had solid propellant boosters and liquid propellant cores (correct?). How much more solid propellant is there in the Ares I versus the Delta II and Titan IV?

 

[tanstaafl76]

So forgive the layman request for clarification here, but my understanding is that the primary claim here is that the occupants of the capsule could not survive an early mission abort resulting from catastrophic explosion of the SRB because the highly disbursed fragments of burning solid rocket fuel would surely result in parachute failure, so even if the occupants survived the explosion itself, they would then plunge to their deaths with a hole-filled parachute, correct?

I was a bit surprised the capsule occupants could survive the event itself, I would think the force from the large exploding SRB alone would be enough to kill them, especially with the capsule stacked directly on the SRB as it is in Ares I. But this has always been the case with this rocket in particular and I figured they were planning on addressing it through extra precautions in the manufacturing of a reliable SRB since that would essentially be the primary source of catastrophic launch failure in this rocket design.

On the other hand, if the crew could really could survive such a catastrophic explosion, and they just need to figure out how to get back down safely, it seems like that's a much easier problem to fix. For instance, why couldn't they have the escape system propel the capsule higher prior to the parachutes deploying to avoid the SRB debris, or if they are still worried about it descending through the debris field, they could even hook up some sort of balloon device or parafoil that could carry the capsule laterally out of the fallout area prior to descending.

 

[radarredux]

the primary claim here is that the occupants of the capsule could not survive an early mission abort resulting from catastrophic explosion of the SRB...

That is what I am thinking, but I would like to hear someone with some authority and knowledge speak on the subject. The reason this is raising red flags for me is that this could potentially doom all the shuttle-derived solutions (Ares IV, Shuttle-C) for manned launches because IIRC they all involve large SRBs. This is more than just an issue with the Ares I.

I recall a year or two back comments on a capsule video of a Soyuz launch, and how super smooth their ride to space was compared to the Shuttle crew's jerky ride, which I believe was largely attributed to the SRBs. Then there was the stories that the Ares I was going to have such strong vibrations that it could potentially kill the crew (hence a lot of time (and loss of available mass?) to build a dampening system). Then there was the stories that the Ares I-x vibrations might be strong enough to damage the self-destruct mechanism. Now the stories that a capsule could not survive the debris cloud from the Ares I destruction.

I am beginning to think solid fuel rockets and humans don't belong together.

 

[drwayne]

Tangential note. There is a tendency to think that liquid fueled rockets are generically "smoother"
than solids. Please note that the Saturn 5 and Titan are two example of liquids that afforded
a very bumpy ride at times in the fight profile. Man rating the Titan because of this was a bear.

Wayne

 

[ThereIWas2]

...especially with the capsule stacked directly on the SRB as it is in Ares I.

This is not true. There is the whole second stage in between.

In any case, the escape system is useful only when you know about something going wrong before it explodes. For example in the case of the Challenger, if a camera had been in the right place so that somebody could see the flames coming out the side of the SRB, they could have done an abort right then, not 60 seconds later when it was too late. (Assuming the Shuttle had an abort-during-boost capability, which it did not.) In Apollo, the Commander could initiate an abort with his hand controller - that certainly requires at least human reaction time after him observing something going wrong. Several seconds at least - in Apollo 12 Pete Conrad had his hand on that control all the way thru the lightning strike and the subsequent loss of all command-module instrumentation and fuel cell power and its pretty interesting that he was that cool.

Any abort system that can yank you away from an explosion faster than the expanding wavefront of the explosion itself is likely to kill you anyway.

 

[CalliArcale]

Any abort system that can yank you away from an explosion faster than the expanding wavefront of the explosion itself is likely to kill you anyway.

I'd just like to point out that this is not necessarily true, and there is evidence against it. Tests of the Mercury and Apollo LAS systems did not demonstrate unsurvivable G loads. And then there is the crew of Soyuz T-10A (also called Soyuz T-10-1, though officially it really had no designation). It was supposed to have flown the Soyuz T-10 mission, but the launch vehicle exploded on the pad. The crew (Vladimir Titov and Gennady Strekalov) were saved by the LAS, which fired and pulled them clear of the exploding Soyuz rocket. Both men not only survived but went on to make additional spaceflights. (Titov even rode twice aboard the Space Shuttle -- once on Atlantis, and once on Discovery.)

 

[drwayne]

Another tangent - Gemini employed ejection seats as an abort method.

Wayne

 

[tanstaafl76]

Wouldn't ejection seats hold the same risk of parachute failure combined with the inherent danger of the astronauts themselves being impacted by 4,000 degree chunks of flaming solid rocket booster fuel? I think I would take my chances as the marble in the tin can at that point!

 

[CalliArcale]

Wouldn't ejection seats hold the same risk of parachute failure combined with the inherent danger of the astronauts themselves being impacted by 4,000 degree chunks of flaming solid rocket booster fuel? I think I would take my chances as the marble in the tin can at that point!

Yes, and in the specific case of Gemini, there were real concerns about whether they would be useful in a pad abort situation, since they couldn't get the crew very far away from the pad -- and since a horizontal ejection is dangerous anyway, especially near the ground. That said, there have been some remarkable survival stories from aircraft ejections near the ground, including some in very unstable circumstances. One famous example is Neil Armstrong's ejection from an LLTV during Apollo training. The thing had rolled almost 90 degrees when he ejected, but he was fine, of course, and went on to glory on Apollo 11. Of course, an LLTV doesn't blow up quite like a hypergolic rocket loaded with thousands of pounds of toxic hydrazine and N2O4.

I think I'd favor the LAS rocket too.

 

[newsartist]

No egress system, air or spacecraft carries a 100% assurance of survival. They improve your chances massively, but aren't foolproof.

This report only covers one failure mode, and one that has been rarely seen.

A detonation of the booster from a case failure is a 'worst case' scenario, and most likely to happen without warning. Even there, it is quite possible that a crewmember could initiate an escape attempt. There are range camera stills of upper stages, and intact payload fairings rising out of similar fireballs.

I am curious where the 4,000 degree figure for the burning chunks comes from? Solids generally need pressure to maintain rapid combustion. If a case is ruptured, through accident, range destruct, or thrust termination, it burns at a far slower, (lower temperature?,) rate. Both SRBs on the 51L flight were destroyed by the Range Safety Officer.

There would certainly be risk from parachute contact with burning material, after a detonation but I wonder about the radiation environment in all but the outer shell area of the fallout pattern where the debris is concentrated.

The capsule would be pulled clear of all but a (upward, if it fired that way?) fraction of the debris. Much of it would be falling faster than the capsule, and an early drogue deployment would keep it above almost all of the rest.

The really important question, is why was this report 'leaked' at this time. Similar studies are done on every program. Have you ever seen another?

 

[drwayne]

With respect to Gemini, I have read some material that suggested that there was enough concern about the
sequencing required for the escape tower to operate properly, that they "liked" the ejection option, with
its own limitations better.

There was also apparently a weight savings that was really not needed for the Gemini mission per se, but
there was a certain amount of effort going into keeping the program going - given the problems that
Apollo was haing at the time.

Wayne

 

[CalliArcale]

There are always trade-offs.

One thing worth mentioning is that the Gemini system gave them a remarkable advantage over Vostok when performing spacewalks -- those ejection seats required big hatches over each seat, so it was easy to get in and out (although it did require depressurizing the entire vehicle, which meant that both crew had to be suited). I seem to recall reading some specific things on EVA that were only possible because of those big swinging doors, but I don't recall exactly what they were. Anyway, those big doors were only there because of the ejection system (otherwise, they'd've had a single hatch rather than two doors), so the system ended up buying them more than just a way out in an emergency situation.

 

[drwayne]

Though they made for a somewhat - awkward - docking situation if one wanted to do an Apollo like
transfer.

 

[tanstaafl76]

Rumor has it they are looking at putting Lamborghini-style scissor doors on the next capsule to drum up popular support from the urban crown

 

[steve82]

.

The really important question, is why was this report 'leaked' at this time. Similar studies are done on every program. Have you ever seen another?

Sort of reminds me of Edison's propoganda movies of an elephant being electrocuted to try to sway people away from Westinghouse's alternating current.

 

[newsartist]

There are always trade-offs.

One thing worth mentioning is that the Gemini system gave them a remarkable advantage over Vostok

That is an unfair, apples v oranges, situation for Vostok.

True, that Leonov, (the only "Vostok" EVA,) had a 'slight' problem getting back in! That doesn't reflect that the design was never intended for second generation activities, like EVAs or multiple passengers. Both exercises carried enormous risks, as lashed up, sans abort ability.

It was robust, and went on to fly as many, many unmanned spacecraft, and may still be used today (?).

Gemini faced a more benign 'explosion', (but far more deadly toxic,) scenario. The seats ALMOST made sense. U-2 and SR-71 crewmen ride essentially the same suits today.

 

[gunsandrockets]

"With respect to Gemini, I have read some material that suggested that there was enough concern about the sequencing required for the escape tower to operate properly, that they "liked" the ejection option, with its own limitations better."

I've read the same things too. People are too quick to denigrate the Gemini escape system. For a two man spacecraft I think ejection seats make a lot of sense.

With an Mercury capsule type rocket tower, even when there is no emergency, in every single mission the tower must jettison or the mission is a failure. That's just one more thing that might go wrong. Whereas ejection seats can remain quiescent unless they are needed in an emergency.

Because of it's ejection seat escape system, Gemini was probably the only operational spacecraft with which the crew had an excellent chance of survival when recovering at sea or on land. The Gemini ejection seats also provided an emergency backup to potential parachute failure of the capsule.

Considering the variety of ways a flight might fail from launch all the way to recovery, an ejection seat provides a more versatile means of escape than a rocket tower. Ejection seats are also adaptable to larger winged and lifting body spacecraft, unlike a rocket tower. The Soviet Buran provided ejection seats for the four crew on the flight deck.

Unfortunately a Dragon style capsule stuffed with seven men is not suited for ejection seats and will have to use a tower.