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?
Quote from: zodiacchris on 09/13/2022 10:23 pmBut 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.
Quote from: chopsticks on 09/13/2022 10:36 pmQuote from: zodiacchris on 09/13/2022 10:23 pmBut 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.
Quote from: chopsticks on 09/13/2022 10:36 pmQuote from: zodiacchris on 09/13/2022 10:23 pmBut 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.
Quote from: alastairmayer on 09/14/2022 12:09 amQuote from: chopsticks on 09/13/2022 10:36 pmQuote from: zodiacchris on 09/13/2022 10:23 pmBut 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.
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.
Quote from: Hog on 09/12/2022 09:32 pmQuote from: dglow on 09/12/2022 09:05 pmSo 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 flightsAh, you're right, it was through STS-4. My mistake.QuoteDont 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.Quote from: Bob Shaw on 09/12/2022 11:37 pmAbsolutely. 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.
Quote from: dglow on 09/12/2022 09:05 pmSo 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
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.
Dont take Manleys videos as gospel.
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.
Quote from: dglow on 09/13/2022 11:21 pmQuote from: chopsticks on 09/13/2022 10:36 pmQuote from: zodiacchris on 09/13/2022 10:23 pmBut 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.
so starship will not have an independent abort systembut 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 levelso 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 boosterand 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 umand 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
Quote from: dglow on 09/14/2022 01:46 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.
...But this argument is moot. Starship is not N1, it can't start its engines prior to staging.
Quote from: Robotbeat on 09/14/2022 02:03 amQuote from: dglow on 09/14/2022 01:46 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:
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.
“Will Crew Starship have abort capability?”“Not if they design it to not have abort capability! I’m smart!”
Quote from: Robotbeat on 09/14/2022 02:31 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.