Space Shuttle Abort Modes
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- Опубліковано 6 січ 2022
- How did NASA plan to get the Space Shuttle back if they had engine issues or their cooling system stopped working?
This video discusses the different abort modes that that Space Shuttle could use to try to get back home safely.
@Eric_Gunnerson on Twitter
Triabolical_ on Reddit - Наука та технологія
In other words. RTLS is a wing and a prayer. Great video.
Quick side note. For TAL prep, they would send an astronaut to Rota, Spain and we would fly the astronaut around to observe weather at one of the three sites (Zaragoza, Marrakesh, and I forgot the city in France). I guess that depended on the Shuttle load. We never flew them south of Morocco so I'm not sure if that was covered. It was a lot of fun and very interesting to hear the launch on a satellite walkie-talkie. Sometimes the launch would be delayed and we'd land and grab a hotel. I had a lot of good memories of Marrakesh that way. On a funny note, one of the astronauts brought a surfboard to Madrid for a Zaragoza flight... Not sure what he was thinking... Lol.
When John Young says a procedure needs miracles you know it's sketchy. It reminds me of a documentary aboard a deep ocean fishing boat where the hull got holed and the procedure for the crew was to chop bits of wood the same shape as the crack and hammer them in to reduce the leak. In theory the wood swells up and fills the cracks. In practice they didn't get enough wood into the gaps to make much difference but fortunately the bilge pumps could deal with the leak and once they got back to port the captain said "that gave the chaps something to do anyway". Or as Mike Mullane said "no point dying all tensed up".
On that one mission where an actual abort was done a second engine sensor also failed, and the computer wanted to shut it down and abort.
Fortunately one of the ground controllers assumed correctly that it was just a faulty sensor and overrode the abort.
If the abort had proceeded it would have probably ended in disaster with the loss of orbiter and crew.
For all its achievements the Shuttle was a total kludge..
In several ways the Shuttle behaved more like a plane than a space ship. Interestingly enough this also seems to cover the survivability during the start/launch.
On a regular plane there is V1 and V2. When you reached V1 you cannot safely abort the launch anymore - and when you don't reach V2, then you cannot launch. So when you have got an engine issue after V1 so that you cannot reach V2 anymore, then this can easily end in a fatal situation - just like with the STS when there is an engine failure at some unfortunate time.
Thank you for sharing your knowledge and for the visuals!
I’ve tried the RTLS many times in the old orbiter 2010 sim and KSP
So many things to get right, and it was still a crapshoot!
Most scenarios (at best case), I could turn around and put the debris field in a very easy search area for the investigators!!
Shuttle commanders spent a ton of time in the shuttle training aircraft to be able to land the shuttle on a normal return, and RTLS is an unnatural act when it comes to flying machines.
It’s always great to watch your videos while playing some Kerbal space program
Concerning STS-51F: AFAIK there had been a sensor issue with another engine as well and shutting it down would meant that neither ATO nur TAL had been possible, meaning it most likely had ended in LOC when they hadn't manually blocked the shutting down of that engine. I'm definitely no expert but AFAIR there had been other black zones than only when all three engines failed. But possibly this was depending on the mission profile.
You are correct.
At that point, unless you have good data that the engine is going to blow up you are better to inhibit the shutdown and hope it is a sensor issue.
LM5 has a great video with the JSC communications, even the Flight Director was getting nervous when he asked if they were past TAL.
@@nolancain8792 who is LM5? I don't know that channel.
@@annando Lunar Module 5
Awesome vid...... Thanks and keep them coming
Gemini 6 had a pad abort but fortunately Wally Schirra kept calm and didn’t activate the ejection seats. Would’ve ruined the ship and hurt the crew if he had. They launched on the next try. Apollo 13 lost an engine early on one of the Saturn stages but just burned the rest a bit longer than normal
The shuttle had at least one pad abort as well and idk if there were more.
I read that the astronauts weren’t fans of the bailout pole.
One of the pad aborts (RSLS abort) was actually also STS-51F. It was the only shuttle mission to have both a pad abort (which weren't unheard of) as well as the only in-flight abort. Yet they completed the mission just fine. You can start to see why they got overconfident about the Shuttle...
Very good work thanks for sharing
Excellent video, thanks.
Great video. I know the subject was aborts after launch but the space shuttle did have several aborts prior to launch, known as RSLS aborts. If the RSLS abort occurred before “main engine start”, it was fairly easy to reschedule the launch as it required less work to re-set everything. If it occurred after main engine start, much more work was required to reschedule.
The STS 51-F mission had an RSLS abort, which occurred after main engine start and if I am correctly remembering what I read, the same issue that caused that RSLS abort led to the ATO abort when they did launch.
That would have been an interesting addition to the topic if I had thought to include it.
Great stuff
If the original design with the orbiter on top of the stack had been used, it would have been safer. But the department of defense wanted more cargo space.
If you want the details for why the design decisions were made, "The Space Shuttle Decision" goes into the justifications. You can find it here:
space.nss.org/the-space-shuttle-decision-by-t-a-heppenheimer/
Very interesting. I didn't know much about the abort modes until now.
Very underrated channel
Hey, you didn't cover RSLS aborts, which also happened to STS-51F making it the only shuttle mission to have two different aborts (one on the pad and one in flight) on top of being the only abort in flight.
Looking forward to the next vid on Starship! I looked at it myself a little bit and it seems there's even a bit of wiggle room if you can't shut off all the Raptors
(I found abort modes were quite cut and dry with Starship - with it being all liquid - so I tried to think of a scenario where the engines continued to burn like SRBs)
I find the lack of SRB Failure abort options a bit appalling. Were SRBs seen as reliable or were there really no options?
Really no options, when SRBs are started that's it. You can't turn them off. And if they fail it usually goes out in an explosion. Anything like ejection seats and the likes would most likely go through the exhaust of the SRBs and get destroyed. And aborting the entire Shuttle simply wouldn't be an option.
The Energia-Buran system didn't have this problem since it used liquid boosters so they had several abort options during this period of the flight iirc. Was hoping he would make some comparisons to it but alas.
US congress valued helping military contractor Thiokol/ATK/Northrop Grumman more than the lives of astronauts. The Russians thought using solid boosters for crewed launch is insane and refused to do it when copying the shuttle.
That would have been an interesting comparison.
There were options.
NASA got pushed to the SRBs because they would be cheaper to develop than the liquids that they had been considering all along. I imagine that the decision made a number of people at NASA upset but have never heard any stories that would support that.
NASA got pushed to Thiokol's design for political reasons; Senator Frank Moss was on the NASA budget committee and came from Utah, as did NASA Administrator Fletcher.
The worst part is that the failure came from NASA. Thiokol had looked at early data from the SRB launches and knew that there was a possible issue from the design and had been lobbying NASA to fix it, but NASA was uninterested. And - of course - the Thiokol engineers were flat out against launching Challenger in those temps.
But NASA played the "nice contract you have there, be a shame if anything were to happen to it" card and Thiokol management caved.
It's possible that NASA would have gotten lucky with the original design the rest of the program and/or would have agreed to a redesigned joint if Challenger had never happened.
If you want more, "Truth, Lies, and O-rings" by Allan McDonald is a great book.
The Orbiter itself was fragile, but the absolute best flying machine EVER built. Challenger was destroyed because of an SRB failure. The loss of Columbia was due to a failure of the ET. I'm sure you know that already. But don't trash the Shuttle Orbiter because the components surrounding it failed.
And NONE of what you're rambling about, NEVER happened....
Abort to orbit happened once.
This is fantastic and so helpful for research, thank you for making it!
Another great one as always. Your channel fills my demand for space history and more technical rocket science stuff that other channels don’t provide
Realized how unsafe the shuttle was, good that we switched to Starliner for 2010’s, would love more shuttle stuff, close calls and also a Starship abort video
Although I’m skeptical about crew starship. Re entry starships will be cargo/tanker, expendable cargo won’t come back and crew will be on lunar starship on orbit which won’t come back
Kind of ridiculous that the proposed shuttle replacement which was canceled in favor of the better Starliner which was Ares 1 would’ve had almost as bad abort capabilities because of that solid underneath them, but SLS will be a very safe vehicle with Orion’s powerful abort system
One of the biggest questions I have is what would have happened if Challenger and Columbia disasters never happened. I imagine we would have seen the shuttle not only fly longer but alternate space hardware and projects would have happened like Shuttle MK2 instead of or along with Orion for the constellation crew exploration vehicle in 2010’s since NASA would have been less safety paranoid - something can clearly be seen with the conservative capsule designs of Starliner and Orion, shuttle may have continued flying into the 2010’ and retired 10 years later in 2020 in favor of commercial crew and Artemis/SLS/COLS. Also Shuttle C filling in for SLS block 1 in 2010’s and getting to moon a decade earlier I imagine
That’s what would have happened if Columbia didn’t happen I imagine, but challenger is even more interesting - would have SLC-6 vandenberg launches specifically for the Air Force to MOL (manned orbiting lab) which would have been an 80s/90s space station before MIR and ISS but after the failed Skylab
Potentially even an upgraded big shuttle design like Pathfinder in For All Mankind
Video about if those disasters never happened and these projects did happen would be quite interesting
Thanks for the kind words. I was happy to find the ECAL stuff, which frankly is just a bit nuts; we'll just take the shuttle into what random airport happens to be nearby.
My opinion is that shuttle 2.0 was never in the cards, and that's because shuttle was about employment, money, and votes rather than capability. Bureaucracies inherently like programs that are long-lasting and stable - ones where it is easy to get mostly the same budget year after year. They do not like risky development programs where you have to ask for more money and then justify why you need the extra money.
Starliner for the 2010s? It first launched 11 days before the end of the decade lol
If I recall Gemini did have an option to use it's deorbit motors to separate the capsule when the seats couldn't be used. Sorta making it a lousy pusher type escape system.
It did, but it could only work during the second stage burn, it couldn't "outrun" the first stage and would recontact the rocket and probably send both out of control.
The ejection system had a serious issue, though: the cabin was pressurized with pure oxygen, as were the flight suits. It was never tested with the cabin pressurized this way, and it would probably light the astronauts on fire. It also wouldn't carry them far clear of the craft and there was a risk that they'd fall into the hypergolic mess of the first stage breaking up.
Somehow still less scary than some of the STS abort scenarios.
Suppose a time traveler was able to sabotage the two main buses or break one of the thermal windows as such that the crew of STS-107 would be forced to abort via RTLS, which seems extremely difficult to do by itself, but we know now it wasn’t impossible. Would Columbia survive?
Interesting question.
I don't think the damage to the carbon carbon reinforce leading edge of the wing would have measurable impact on the chances of RTLS succeeding. IIRC from the columbia accident report, the telemetry identified the location of the hole quite well, and that means it was a small hole that didn't propagate across the whole front of the wing. Given that they made it through ascent without any obvious control problems, I think that means they are fine for RTLS.
Well, as fine as you could ever be for RTLS.
Probably would have had no measurable chance than any RTLS abort and I agree with John Young it was Russian roulette.
I just remembered something that I read some time ago. When STS had derived from course during the first two minutes, then the FTS had to be executed - which would have resulted in the death of the crew. Imagine the responsibility of the person flipping that switch, knowing that this flipping would kill people ...
Great information! This is actually the first place I've ever heard an RTLS being described as potentially doable during a two-engine-out situation. Everything else I've ever read or heard (including recent information) stated that a two-engine-out before Droop or single-engine-TAL would result in a contingency abort to an ECAL or bailout. I looked through the workbook you cited but didn't find any information backing that up. Can you provide any documentation specifically for two-engine-RTLS? I'm not trying to say you're wrong, I'm genuinely curious as to if what I've heard in the past was inaccurate. Thanks!
If I'm right - and it's possible I'm not as the information on the less common aborts is a bit sketchy in places - you'll find the information in one of the three references I talk about. My *guess* is that it's in the contingency abort one.
The requirement for RTLS is that you can stay high enough in the air to burn off the fuel in the external tank so you can jettison it (assuming that you aren't willing to just punch it off and hope for the best - probably a good choice if you would otherwise crash) while at the same time have enough altitude and airspeed to do something useful.
@@EagerSpace Hmm...I'll have to do some research on that, then. If I come up with anything definitive, I'll give you a heads-up on it.
6:19 damn 😂
Holy smokes that thing was a deathtrap, glad we got rid of it. There's something to be said for simple, elegant engineering like an escape tower and capsule. It's simply the safest way to traverse to/from space. They figured it out right the first time.
The big problem with shuttle IMO was that NASA built it but had no plan - and no money - to improve it incrementally. If they had we could have gotten a vehicle that was much better in later versions.
After the initial Soyuz 1 fatal crash (April 24, 1967) and the Soyuz 11 decompression accident (June 30, 1971), the Soviets/Russians haven't had a fatality in 51 years. They chose a relatively simple design and periodically upgraded the spacecraft. Amazing safety record.
@@TomTimeTraveler That may have changed if Buran had ever had manned flights.tho, and the US Shuttle and Russian capsule craft are so different that abort mode and flight safety comparisons aren't really an equal one.
It did claim prolly more lives than any other space launch system
@@markrix Sad but true.
I have to say - your channel is really fantastic and I appreciate how you combine simple diagrams with clear commentary to explain complex topics. Keep it up.
Thanks. This one ended up being much more complex than I expected...
man i fucking love your videos
Thanks, I appreciate it.
Did they plan aborts for Vandenberg launches also?
I presume they were working on that before Challenger, but I don't know any details. There are some Islands in the south Pacific that might have runways long enough to handle shuttle.
AOA could land back in California.
Hi Eager Space: Very nicely done. If I may, I would like to add one thing regarding RTLS. Regarding the 'Acts of God' that were required, the Powered Pitcharound maneuver required gimbal angles of the Space Shuttle Main Engines that introduced structural loads that the Orbiter Aft Fuselage never got 'officially' qualified for. Not a good omen. Thank you.
The abort mode timeline on Wikipedia seems to suggest that Shuttle had recoverable abort modes during SRB flight _with a 3-SSME failure_ . Could the Shuttle actually maintain control on SRBs alone or am I misreading the graph?
Two questions there...
The SRBs do have a nozzle that gimbals and they put out about 4 times the thrust of the RS-25 engines, so they are the primary steerers and I'd expect they could maintain control.
IRC, the training information I read says that detaching the shuttle from a full external tank is not survivable because of the collision potential; that's why the RTLS trajectory did fuel wasting. But the training information does have some holes in it.
If they could separate, RTLS is out because they don't have the power to do it. Maybe they could get into a stable glide and go out the side hatch.
@@EagerSpace Thanks! Do you know why re-contact is/is not a danger depending on fuel state? The only way I can see it is that in negative AoA state the Shuttle generates negative lift pressing it towards the tank, but by the same token I don't know why they can't just do an early roll and detach the tank
@@dsdy1205 That might be covered in the discussions about the dead zones.
@@EagerSpace right sorry, missed that
What about a reentry abort to orbit say 5 to 7 minutes prior to loss of signal? At what point is the shuttle committed to deorbit?
As soon as the shuttle completes the deorbit burn, it's committed to reentry.
I remember astronaut Bob Crippen saying in an interview he thought having ejection seats in Columbia were not practical for a number of reasons and were installed more or less to appease the public who questioned the safety of the shuttle.
That probabalistic risk assessment that NASA did later - during the shuttle program - estimated that the shuttle risk of losing a crew went from 1 in 12 on the first four flights to 1 in 10 after the removed the ejection seats.
So they helped a bit, but the scenarios in which they were usable were limited.
What was the plan if the Shuttle landed in europe? Put the Shuttle on a boat to send it back?
They would have flown over the 747 shuttle carrier aircraft and put the shuttle on top and flown it back...
The problem is that there's a specialized crane known as the "mate/demate structure" that they would have needed to get to Europe, or come up with some other method to do the same task.
@@EagerSpace i was under the impression the carrier was range limited but it seems that they flew enterprise to the paris air show. en.m.wikipedia.org/wiki/Shuttle_Carrier_Aircraft .I wonder how they did that. What the flight plan was. Did they stop in gander, thule, iceland. Did they somehow carry more fuel?
@@kfrdubber There are some routes that would work listed here: www.sky-ferry.com/index.php/about/flying-the-atlantic/
@@EagerSpacethey had a mobile mate/demate crane device
Kinda surprised that 51-F was the only abort
Yes, the only flight abort. There were quite a few on-pad aborts, including at least one after main engine start.
The shuttle was very dangerous even though it had great capabilities for payloads.
Lol whats with the face. Cool I guess.
The Space shuttle as implemented was a complete and total waste of time and treasure- Perhaps as long as it was up there circling around it made sensé to repair Hubble which should hava been built right to begin with and the ISS was pointless other that Astronaughts learning how to eat à banana launched spinning weightlessly - As far as testing human endurance in long term microgravity for à trip to Mars- Well we figured out that by the Time we got there, the human body wouldn't be able to function which everyone already knew as well as they knew some form of rotating centrifugal gravity would have to be used - THIS IS STUFF I UNDERSTOOD AS A YOUNG MAN IN 1964 - IN other Words the shuttle was a military platform at Best