Author Topic: Abort options for Starship and Starship/SuperHeavy  (Read 312788 times)

Offline chopsticks

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #140 on: 09/13/2022 10:36 pm »
But can SS technically do a pad abort, given that the engines need to be pre-chilled before ignition, something that is only done during Stage 1 flight after launch on F9? Can SS fire it’s engine without having separated from the first stage, given that it sits on top of the booster with no place for the exhaust gas to go? I am not aware of any blow out panels in the Booster interstage. It seems to me that an attempted pad abort with these limitations would result in a massive explosion, rather than lift off.

What am I missing?

I don't think you're missing anything. I don't see how a SS could fire up all of its engine while sitting on the booster without a huge fireball.

Maybe if it was designed for hotstaging something like this could work.

Offline dglow

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #141 on: 09/13/2022 11:21 pm »
But can SS technically do a pad abort, given that the engines need to be pre-chilled before ignition, something that is only done during Stage 1 flight after launch on F9? Can SS fire it’s engine without having separated from the first stage, given that it sits on top of the booster with no place for the exhaust gas to go? I am not aware of any blow out panels in the Booster interstage. It seems to me that an attempted pad abort with these limitations would result in a massive explosion, rather than lift off.

What am I missing?

I don't think you're missing anything. I don't see how a SS could fire up all of its engine while sitting on the booster without a huge fireball.

Maybe if it was designed for hotstaging something like this could work.

Even if it could work, it wouldn't pull away from the booster fast enough to matter.

Offline alastairmayer

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #142 on: 09/14/2022 12:09 am »
But can SS technically do a pad abort, given that the engines need to be pre-chilled before ignition, something that is only done during Stage 1 flight after launch on F9? Can SS fire it’s engine without having separated from the first stage, given that it sits on top of the booster with no place for the exhaust gas to go? I am not aware of any blow out panels in the Booster interstage. It seems to me that an attempted pad abort with these limitations would result in a massive explosion, rather than lift off.

What am I missing?

I don't think you're missing anything. I don't see how a SS could fire up all of its engine while sitting on the booster without a huge fireball.

Maybe if it was designed for hotstaging something like this could work.

Just so I understand, do you think the stack is designed so that after separation, SS just coasts for however long it takes to prechill the engines? In tests so far, that seems to be at least a few minutes.

Offline Robotbeat

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #143 on: 09/14/2022 12:09 am »
But can SS technically do a pad abort, given that the engines need to be pre-chilled before ignition, something that is only done during Stage 1 flight after launch on F9? Can SS fire it’s engine without having separated from the first stage, given that it sits on top of the booster with no place for the exhaust gas to go? I am not aware of any blow out panels in the Booster interstage. It seems to me that an attempted pad abort with these limitations would result in a massive explosion, rather than lift off.

What am I missing?

I don't think you're missing anything. I don't see how a SS could fire up all of its engine while sitting on the booster without a huge fireball.

Maybe if it was designed for hotstaging something like this could work.

Just so I understand, do you think the stack is designed so that after separation, SS just coasts for however long it takes to prechill the engines? In tests so far, that seems to be at least a few minutes.
The engines are pre-chilled well before separation. Maybe even on the pad.
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Offline Robotbeat

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #144 on: 09/14/2022 12:11 am »
But can SS technically do a pad abort, given that the engines need to be pre-chilled before ignition, something that is only done during Stage 1 flight after launch on F9? Can SS fire it’s engine without having separated from the first stage, given that it sits on top of the booster with no place for the exhaust gas to go? I am not aware of any blow out panels in the Booster interstage. It seems to me that an attempted pad abort with these limitations would result in a massive explosion, rather than lift off.

What am I missing?

I don't think you're missing anything. I don't see how a SS could fire up all of its engine while sitting on the booster without a huge fireball.

Maybe if it was designed for hotstaging something like this could work.

Even if it could work, it wouldn't pull away from the booster fast enough to matter.
Based on what? Handwaves? Even a slow pull away would increase survivability over none.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline alastairmayer

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #145 on: 09/14/2022 12:12 am »
But can SS technically do a pad abort, given that the engines need to be pre-chilled before ignition, something that is only done during Stage 1 flight after launch on F9? Can SS fire it’s engine without having separated from the first stage, given that it sits on top of the booster with no place for the exhaust gas to go? I am not aware of any blow out panels in the Booster interstage. It seems to me that an attempted pad abort with these limitations would result in a massive explosion, rather than lift off.

What am I missing?

I don't think you're missing anything. I don't see how a SS could fire up all of its engine while sitting on the booster without a huge fireball.

Maybe if it was designed for hotstaging something like this could work.

Just so I understand, do you think the stack is designed so that after separation, SS just coasts for however long it takes to prechill the engines? In tests so far, that seems to be at least a few minutes.
The engines are pre-chilled well before separation. Maybe even on the pad.
So the SS could launch from the booster on the pad.  If the situation is dire enough to need to do that, nobody is going to care what happens to the booster, which may already be in the process of exploding.

Offline Lee Jay

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #146 on: 09/14/2022 12:47 am »
Maybe they could put a LAS stage between the booster and the SS for manned flights. It would basically be a ring of SuperDracos. If the LAS isn't needed (which hopefully will be always), it disconnects from SS and connects to SH before separation.

It'll need about 3,100 of them.

Offline chopsticks

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #147 on: 09/14/2022 12:50 am »
But can SS technically do a pad abort, given that the engines need to be pre-chilled before ignition, something that is only done during Stage 1 flight after launch on F9? Can SS fire it’s engine without having separated from the first stage, given that it sits on top of the booster with no place for the exhaust gas to go? I am not aware of any blow out panels in the Booster interstage. It seems to me that an attempted pad abort with these limitations would result in a massive explosion, rather than lift off.

What am I missing?

I don't think you're missing anything. I don't see how a SS could fire up all of its engine while sitting on the booster without a huge fireball.

Maybe if it was designed for hotstaging something like this could work.

Just so I understand, do you think the stack is designed so that after separation, SS just coasts for however long it takes to prechill the engines? In tests so far, that seems to be at least a few minutes.

No, in a normal flight profile the upper engines are chilled before stage separation, presumable Starship will be the same. If you wanted the Starship upper stage to be able to liftoff from the booster while sitting on the pad, the engines would need to be pre-chilled extra early.

Offline Hog

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #148 on: 09/14/2022 01:16 am »
So Gemini and STS-1 and -2 were the only ground-launched US spacecraft to fly with ejection seats. And just the other day I learned (possibly from a Manley video) that Shuttle's seats could not provide for a pad-escape – only usable in-flight.
STS 1-4  had the seats  as well as the 8 atmospheric crewed Enterprise flights

Ah, you're right, it was through STS-4. My mistake.


Quote
Dont take Manleys videos as gospel.

Okay. Do you have better info to offer, or is that just some broad-brush shade?  ::)

What Manley stated is that Shuttle's seats didn't angle upward, as Gemini's did, which made them useless for a pad escape.


Absolutely. Either a capsule or capsules or pods. None of this is new, von Braun wanted such things in the 1950s for his big winged shuttle. The F-111 had a pod, as did the XB-70. Lives have repeatedly been saved by capsules, and lost for the lack of them.

The B-58 as well.
I just said don't take them as gospel. He and his team research to their best, but everyone makes mistakes.  Take in all sources available, Manley's is a great one.  NSF.com is even better.   We're all here to learn.

XB-70 had individual escape pods a la Hustler B-58,

https://www.youtube.com/watch?time_continue=33&v=CxEeKWy45IQ&feature=emb_logo

similar to individual system used in XB-70.
http://www.alternatewars.com/SAC/XB-70_Escape_System_-_Paper.pdf

much different than the F-111 capsule and the first 3 protototype B-1A systems.

B-1A


The Shuttle systems came from the SR1 ejection system used in the USAF blackbirds SR71. In those birds there was no Command Ejection, where any handle pulling would eject all occupants, each crewmember had to pull their own ejection handle. The SEES(Shuttle Ejection Escape Suit) pressure suits were blackbird/U2 issue as well  David Clark Co.

  Those ejection system on STS improved the LOCV odds from 1/9 to 1/12.    Someone said it earlier.  When doing nothing isn't enough.

attachments
1) Here's John Young posing in the SEES
« Last Edit: 09/14/2022 01:28 am by Hog »
Paul

Offline dglow

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #149 on: 09/14/2022 01:46 am »
But can SS technically do a pad abort, given that the engines need to be pre-chilled before ignition, something that is only done during Stage 1 flight after launch on F9? Can SS fire it’s engine without having separated from the first stage, given that it sits on top of the booster with no place for the exhaust gas to go? I am not aware of any blow out panels in the Booster interstage. It seems to me that an attempted pad abort with these limitations would result in a massive explosion, rather than lift off.

What am I missing?

I don't think you're missing anything. I don't see how a SS could fire up all of its engine while sitting on the booster without a huge fireball.

Maybe if it was designed for hotstaging something like this could work.

Even if it could work, it wouldn't pull away from the booster fast enough to matter.
Based on what? Handwaves? Even a slow pull away would increase survivability over none.

Based on Starship test flights modulo the added mass of fully-fueled tanks. Contrast to Orion, Dragon, and Starliner pad-aborts. The presumption is that hypergols and solids deliver thrust on-demand faster than a FFSC engine.

It all depends on scenario. If a pad fire, evacuate thew crew and zip them away in baskets or whatever. If, on the other hand, it's a sudden conflagration of the booster then reaction time will be of the essence.

But this argument is moot. Starship is not N1, it can't start its engines prior to staging.

Offline Robotbeat

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #150 on: 09/14/2022 02:08 am »
Elon said in the February 2022 Starship update that he recommends that Starship should be made able to abort the Ship off the booster even sitting on the pad using a 9 engine version of Starship (possibly under-tanked for crewed missions to increase the T/W ratio in a pad abort situation).

We don't have a 9 engine version of Starship, yet, but it's clear they're intending this capability eventually.

During the Q&A session, with our own Chris G starting at 1:04:08 timestamp:
Quote
so  starship will not have an independent abort system
but i think something that would make sense is to  have the thruster weight of the ship uh be enough that uh it could do um  a a it could take off from uh the booster even if the booster  has a failure at the pad level
so you can get the the thrust weight of the ship  uh at sea level above one then even if there is something goes wrong with the booster the ship can  essentially fly away from the booster
and so that's uh  something that i think would be important for for carrying people uh and also for high value cargo  to have the ship uh have a thrust to eight greater than one even at uh sea level um
and then the there's a like i said that would be like the nine engine version  and and then even if you lost one engine um i think you should still be able to  do an abort so i think for crude missions we would essentially um maybe de-tank the ship to some degree so that  you'd have uh kind of a launch of board capability with the ship even if you lost an engine
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Offline dglow

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #151 on: 09/14/2022 02:14 am »
...
But this argument is moot. Starship is not N1, it can't start its engines prior to staging.
*Can't*? I'd like to see the source for that claim.

Whoa. Hey, is something wrong?


Yes, can't – as currently designed.

Starship's halves are a tight fit. Hot staging wants this:

Online meekGee

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #152 on: 09/14/2022 02:17 am »
But can SS technically do a pad abort, given that the engines need to be pre-chilled before ignition, something that is only done during Stage 1 flight after launch on F9? Can SS fire it’s engine without having separated from the first stage, given that it sits on top of the booster with no place for the exhaust gas to go? I am not aware of any blow out panels in the Booster interstage. It seems to me that an attempted pad abort with these limitations would result in a massive explosion, rather than lift off.

What am I missing?
I don't know if skipping the pre-chill causes the engines to fail or just to lose 100 lives, for example.

Also, the manned SS of which we speaketh, it does not yet exist.  Maybe it'll pre-chill using GSE gas while on the pad?

Also, that future SS might have the blow-out panels you're recommending....

In short what you're missing is that an abort capable SS is still a fair number of fesign iterations away.
« Last Edit: 09/14/2022 02:18 am by meekGee »
ABCD - Always Be Counting Down

Offline Robotbeat

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #153 on: 09/14/2022 02:20 am »
Who said skip pre-chill? Just chill on the pad.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Robotbeat

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #154 on: 09/14/2022 02:25 am »
...
But this argument is moot. Starship is not N1, it can't start its engines prior to staging.
*Can't*? I'd like to see the source for that claim.

Whoa. Hey, is something wrong?


Yes, can't – as currently designed.

Starship's halves are a tight fit. Hot staging wants this:
well sure, but we already know Starship will be redesigned for crew launch (9 engines, for instance) and abort. That’s a really dumb objection.

Might as well object there is no life support or seats!
« Last Edit: 09/14/2022 02:27 am by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Online DanClemmensen

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #155 on: 09/14/2022 02:35 am »
Elon said in the February 2022 Starship update that he recommends that Starship should be made able to abort the Ship off the booster even sitting on the pad using a 9 engine version of Starship (possibly under-tanked for crewed missions to increase the T/W ratio in a pad abort situation).

We don't have a 9 engine version of Starship, yet, but it's clear they're intending this capability eventually.
SpaceX has no crewed Starship at all, much less one with nine engines, so we can use our imaginations.
OK, let's consider a specialized crew launcher. It is a crewed EDL starship optimized solely for getting crew from Earth to LEO and back. It's overpowered, small, and with limited propellant and duration compared to the "nominal" Starship. It has nine or more (up to 33) sea-level raptors, and is designed so the raptors can be put into a ready-to-start state and left in that state for some time while it is sitting atop the SH. It is designed so that it can launch itself from atop the SH without damage to itself (but with damage to the SH) in a very short time, possibly with blowout panels. Crew that is going beyond LEO will transfer to the "real" crewed Starship, which does not need to land on Earth and which is launched without crew.

Does this crew launcher SS meet the launch abort criteria?

Offline chopsticks

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #156 on: 09/14/2022 02:42 am »
“Will Crew Starship have abort capability?”

“Not if they design it to not have abort capability! I’m smart!”

Just stop it. You think you're the one being smart here but you're just acting immature. You were making it sound like it would just blast off as is and dglow was pointing out how this would be problematic. Besides, to account for something like hotstaging, the booster would almost certainly have to be redesigned as well which may or may not add unwanted complication that SpaceX may not want to deal with.

Offline Robotbeat

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #157 on: 09/14/2022 02:46 am »
Just go off of what SpaceX has already communicated. If there are obvious design mods that require what they say their plan is, then it seems reasonable to assume they’ll do them.

(Booster survival isn’t an imperative for an abort.)
« Last Edit: 09/14/2022 03:18 am by Robotbeat »
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Offline dglow

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #158 on: 09/14/2022 03:02 am »
“Will Crew Starship have abort capability?”

“Not if they design it to not have abort capability! I’m smart!”

Seriously, this isn’t like you. I hope everything is alright.

Offline Robotbeat

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Re: Abort options for Starship and Starship/SuperHeavy
« Reply #159 on: 09/14/2022 03:07 am »
“Will Crew Starship have abort capability?”

“Not if they design it to not have abort capability! I’m smart!”

Seriously, this isn’t like you. I hope everything is alright.
Sorry, I’m fine.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Tags: LAS black zones 
 

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