Timeline for Why doesn't the BFR/Starship have a launch escape system?
Current License: CC BY-SA 4.0
14 events
| when toggle format | what | by | license | comment | |
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| Apr 20, 2023 at 22:24 | comment | added | Dagelf | The idea is to have a standard platform that can take a large amount of crew and/or cargo. A separate capsule or compartment adds complexity and risk. | |
| Mar 26, 2021 at 17:53 | comment | added | Joshua | Why so large? The correct way to do it would be to sever the crew compartment from Starship's main tanks. | |
| Aug 23, 2020 at 11:01 | comment | added | Giovanni | @JörgWMittag The possible block of view rather meant the lifeboats. On the Titanic, half of the necessary lifeboats really weren't included because of having too much of them where it might have become 'too full-loaded'. If the BFR/Starship just can't have some kind of LES, astronauts who wanna play it safe better prefer NASA's SLS/Orion which has a standard launch escape tower. | |
| Aug 23, 2020 at 10:49 | comment | added | Jörg W Mittag | … for an actual escape. The argument that I am making is not that a "Launch Escape System would block the view", the argument I am making is that the LES you are proposing is so insanely complex that, if you were capable of building it, you would also be capable of building a rocket that is safe enough to not need it. Again, the LES you are proposing has the same level of complexity as the most complex and most powerful rockets ever built in the history of mankind. | |
| Aug 23, 2020 at 10:47 | comment | added | Jörg W Mittag | … of about 4:1, which sounds barely enough for a LES. So, you would need something as complex as a Saturn V first stage, or multiple Space Shuttle SRBs to even have a hope of getting Starship to safety. (And in all my calculations in all my comments so far, I have always assumed that the weight of the LES is 0, which is of course unrealistic, so an LES would in reality need even more thrust, because it not only has to lift Starship but also itself and its fuel.) Just es a point of comparison: Crew Dragon has 8 SuperDracos. Starship would need 125(!!!) just to hover, and probably up to 1000 … | |
| Aug 23, 2020 at 10:44 | comment | added | Jörg W Mittag | @Giovanni: The Soyuz-U plus its 4 side boosters has less than a million pounds of thrust. Starship weighs 2 million pounds, so even two of them wouldn't be enough to have Starship just hover, let alone actually escape. The reason why the LES was needed on Soyuz T-10-1 was because we haven't figured out how to build such big rockets safely yet, and you are proposing to stick something at least three times the size onto Starship. The biggest rocket ever in the history of mankind was the Saturn V. Its first stage has 8 million pounds of thrust, which would give a thrust to weight ratio … | |
| Aug 22, 2020 at 18:05 | comment | added | Giovanni | @SusanW Yeah the Titanic is unsinkable, why put so many lifeboats on it? The huge cost, the delays and efforts, who needs that? And they might block the view. That's your and Jörgs argument. But in case of the BFR, an escape tower would really be not the best emergency system. Better to have such side thrusters like the Crew Dragon has. And parachutes per crew member wouldn't hurt perhaps, and might have saved the lives of the Challenger crew. | |
| Aug 22, 2020 at 17:53 | comment | added | SusanW | @Giovanni safer? maybe, maybe not. Consider, even with a detachable passenger module (say 100t), this would be an escape tower an order of magnitude larger than anything seen before. Plus 10-20 tons of (world's largest ever) vast parachutes, plus emergency separation mechanism, etc. The extra weight reduces payload/passenger count. If you go from 100 down to 30 passengers (which you might), then you need 3x launches for same total delivery, so 3x random failure exposure, and you've gone to huge cost, delay and effort to make it ... much worse. | |
| Aug 22, 2020 at 5:46 | comment | added | Giovanni | @GremlinWranger A launch escape tower never failed, afaik. It saved the Soyuz T-10-1 crew from death that otherwise would be certain. Not having it led to the death of the Challenger crew which might have been avoided. Ironically, during Mercury-Redstone 1, the LES was the only thing that worked (as well as Mercury's parachute). | |
| Aug 21, 2020 at 23:40 | comment | added | GremlinWranger | @giovanni Done properly you only add things that make things safer overall. Most safety system kill people en.wikipedia.org/wiki/Airbag#Injuries_and_fatalities. If adding launch escape system means people die in landing accidents from leaking fuel or inadvertent operation then it is a net loss. Ideally yes, you design your overall system so that it has abort modes but in some cases you come up against physics that mean your choices are not 'do people die' but 'how many people die'. Note of course the key part of this statement is 'done properly' not 'done for profit'. | |
| Aug 21, 2020 at 18:55 | comment | added | Jörg W Mittag | A launch escape tower that can lift Starship to safety would be multiple Falcon Heavy worth of rockets. | |
| Aug 21, 2020 at 18:12 | history | edited | SusanW | CC BY-SA 4.0 |
minor comment on risk of failure
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| Aug 21, 2020 at 18:06 | comment | added | Giovanni | Still it would be safer to have a launch escape tower, or parachutes, or both. (-: | |
| Aug 21, 2020 at 17:16 | history | answered | SusanW | CC BY-SA 4.0 |