Author Topic: Should Starship (BFS) have a launch escape system?  (Read 231849 times)

Offline Lars-J

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Re: Should the ITS have a launch escape system?
« Reply #120 on: 10/13/2017 04:55 am »
Its LES is pretty much the engines on the bottom of the ship, you can't have an escape system that large.

It's similar to the crewed Dream Chaser's abort system.

...Which they were having problems with, even at Dreamchasers much smaller scale. When DC was dropped from commercial crew, they were in the middle of evaluating new propulsion ideas to replace it. (It was a hybrid system) The cargo DC has no such system.
« Last Edit: 10/13/2017 04:55 am by Lars-J »

Offline pathfinder_01

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Re: Should the BFR have a launch escape system?
« Reply #121 on: 10/13/2017 09:03 am »
By the way, a LAS would add its own risk factors. For instance, if the LAS on Orion fails to separate, the crew dies.
And commercial airlines are so safe that if you added a LAS or ejection seats to them, the extra risks would greatly outweigh the abort advantages, and you'd REDUCE overall safety.

Again, for those in the back:
If BFR is as reliable as Musk wants it to be, adding a LAS would REDUCE safety.

Ejection seats are not practical on any commercial airline because of the wide variation between passengers(300 pound man, baby, elderly woman), number of passengers on a plane(hundreds) and the fact that the passengers would need training. Nobody would think of designing an experimental craft , bomber or a fighter jet without some consideration of escape.

In this time period and age BFR is closer to an experimental aircraft than anything else and If the shuttle had lived up to it's safety claims Columbia and Challenger would not have occurred.


The first BFR flights will not  have such a number of people that it is impossible to put in an LES. In fact I don't think you could find as many people as Elon hopes to travel to the moon, mars or LEO at the price he is offering on any regular bias. The most likely paying passenger at the moment for better or worse is going to be NASA and not private citizens.

Offline JamesH65

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Re: Should the BFR have a launch escape system?
« Reply #122 on: 10/13/2017 10:42 am »
By the way, a LAS would add its own risk factors. For instance, if the LAS on Orion fails to separate, the crew dies.
And commercial airlines are so safe that if you added a LAS or ejection seats to them, the extra risks would greatly outweigh the abort advantages, and you'd REDUCE overall safety.

Again, for those in the back:
If BFR is as reliable as Musk wants it to be, adding a LAS would REDUCE safety.

Ejection seats are not practical on any commercial airline because of the wide variation between passengers(300 pound man, baby, elderly woman), number of passengers on a plane(hundreds) and the fact that the passengers would need training. Nobody would think of designing an experimental craft , bomber or a fighter jet without some consideration of escape.

In this time period and age BFR is closer to an experimental aircraft than anything else and If the shuttle had lived up to it's safety claims Columbia and Challenger would not have occurred.


The first BFR flights will not  have such a number of people that it is impossible to put in an LES. In fact I don't think you could find as many people as Elon hopes to travel to the moon, mars or LEO at the price he is offering on any regular bias. The most likely paying passenger at the moment for better or worse is going to be NASA and not private citizens.

Mitigated by the thought that the BFS/R will spend a considerable proportion of its experimental period being flown by computers with no-one on board.

Offline yg1968

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Re: Should the ITS have a launch escape system?
« Reply #123 on: 10/13/2017 02:33 pm »
Its LES is pretty much the engines on the bottom of the ship, you can't have an escape system that large.

It's similar to the crewed Dream Chaser's abort system.

...Which they were having problems with, even at Dreamchasers much smaller scale. When DC was dropped from commercial crew, they were in the middle of evaluating new propulsion ideas to replace it. (It was a hybrid system) The cargo DC has no such system.

I was under the impression that it was the hybrid motor which was problematic, not the LAS. The acquisition of Orbitec gave them better options for propulsion.

Offline envy887

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Re: Should the BFR have a launch escape system?
« Reply #124 on: 10/13/2017 04:00 pm »
...
The first BFR flights will not  have such a number of people that it is impossible to put in an LES. In fact I don't think you could find as many people as Elon hopes to travel to the moon, mars or LEO at the price he is offering on any regular bias. The most likely paying passenger at the moment for better or worse is going to be NASA and not private citizens.

If there are so few passengers, then they can launch and return on F9R/Dragon 2 until BFR completes hundreds of successful flights.

Offline Robotbeat

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Re: Should the BFR have a launch escape system?
« Reply #125 on: 10/13/2017 11:07 pm »
...
The first BFR flights will not  have such a number of people that it is impossible to put in an LES. In fact I don't think you could find as many people as Elon hopes to travel to the moon, mars or LEO at the price he is offering on any regular bias. The most likely paying passenger at the moment for better or worse is going to be NASA and not private citizens.

If there are so few passengers, then they can launch and return on F9R/Dragon 2 until BFR completes hundreds of successful flights.
Bingo. And how much does, say, 300 flights cost of SpaceX gets costs as low as they want? Just $600m, less than developing a LAS.
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

Offline intrepidpursuit

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Re: Should the BFR have a launch escape system?
« Reply #126 on: 10/13/2017 11:15 pm »
...
The first BFR flights will not  have such a number of people that it is impossible to put in an LES. In fact I don't think you could find as many people as Elon hopes to travel to the moon, mars or LEO at the price he is offering on any regular bias. The most likely paying passenger at the moment for better or worse is going to be NASA and not private citizens.

If there are so few passengers, then they can launch and return on F9R/Dragon 2 until BFR completes hundreds of successful flights.
Bingo. And how much does, say, 300 flights cost of SpaceX gets costs as low as they want? Just $600m, less than developing a LAS.

The Dragon flights will still be very expensive. They will get lots of experience with the ship before they are ready to put people on it anyway, no need to kludge dragon in there.

Offline Robotbeat

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Re: Should the BFR have a launch escape system?
« Reply #127 on: 10/13/2017 11:20 pm »
...
The first BFR flights will not  have such a number of people that it is impossible to put in an LES. In fact I don't think you could find as many people as Elon hopes to travel to the moon, mars or LEO at the price he is offering on any regular bias. The most likely paying passenger at the moment for better or worse is going to be NASA and not private citizens.

If there are so few passengers, then they can launch and return on F9R/Dragon 2 until BFR completes hundreds of successful flights.
Bingo. And how much does, say, 300 flights cost of SpaceX gets costs as low as they want? Just $600m, less than developing a LAS.

The Dragon flights will still be very expensive. They will get lots of experience with the ship before they are ready to put people on it anyway, no need to kludge dragon in there.
We weren't saying kludge a Dragon on there, we were saying launch the Dragon on F9 and transfer crew to the BFR, just like NASA was/is planning for Altair or the Mars transfer vehicle, then return to the Dragon for entry.
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

Offline yg1968

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Re: Should the BFR have a launch escape system?
« Reply #128 on: 10/13/2017 11:26 pm »
...
The first BFR flights will not  have such a number of people that it is impossible to put in an LES. In fact I don't think you could find as many people as Elon hopes to travel to the moon, mars or LEO at the price he is offering on any regular bias. The most likely paying passenger at the moment for better or worse is going to be NASA and not private citizens.

If there are so few passengers, then they can launch and return on F9R/Dragon 2 until BFR completes hundreds of successful flights.
Bingo. And how much does, say, 300 flights cost of SpaceX gets costs as low as they want? Just $600m, less than developing a LAS.

The Dragon flights will still be very expensive. They will get lots of experience with the ship before they are ready to put people on it anyway, no need to kludge dragon in there.
We weren't saying kludge a Dragon on there, we were saying launch the Dragon on F9 and transfer crew to the BFR, just like NASA was/is planning for Altair or the Mars transfer vehicle, then return to the Dragon for entry.

The objective of BFR is to replace Dragon, Falcon 9 and FH. So it would be strange to have to rely on them.

Offline intrepidpursuit

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Re: Should the BFR have a launch escape system?
« Reply #129 on: 10/13/2017 11:28 pm »
...
The first BFR flights will not  have such a number of people that it is impossible to put in an LES. In fact I don't think you could find as many people as Elon hopes to travel to the moon, mars or LEO at the price he is offering on any regular bias. The most likely paying passenger at the moment for better or worse is going to be NASA and not private citizens.

If there are so few passengers, then they can launch and return on F9R/Dragon 2 until BFR completes hundreds of successful flights.
Bingo. And how much does, say, 300 flights cost of SpaceX gets costs as low as they want? Just $600m, less than developing a LAS.

The Dragon flights will still be very expensive. They will get lots of experience with the ship before they are ready to put people on it anyway, no need to kludge dragon in there.
We weren't saying kludge a Dragon on there, we were saying launch the Dragon on F9 and transfer crew to the BFR, just like NASA was/is planning for Altair or the Mars transfer vehicle, then return to the Dragon for entry.

The kludge is making it a part of the system, whether it is built into the rocket or not. It is impossible for BFR to be cheaper than Falcon 9 if you still have to launch a Falcon 9 (or several). They won't put people on BFR until they are comfortable launching them along with it.

Offline Robotbeat

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Re: Should the BFR have a launch escape system?
« Reply #130 on: 10/13/2017 11:29 pm »
...
The first BFR flights will not  have such a number of people that it is impossible to put in an LES. In fact I don't think you could find as many people as Elon hopes to travel to the moon, mars or LEO at the price he is offering on any regular bias. The most likely paying passenger at the moment for better or worse is going to be NASA and not private citizens.

If there are so few passengers, then they can launch and return on F9R/Dragon 2 until BFR completes hundreds of successful flights.
Bingo. And how much does, say, 300 flights cost of SpaceX gets costs as low as they want? Just $600m, less than developing a LAS.

The Dragon flights will still be very expensive. They will get lots of experience with the ship before they are ready to put people on it anyway, no need to kludge dragon in there.
We weren't saying kludge a Dragon on there, we were saying launch the Dragon on F9 and transfer crew to the BFR, just like NASA was/is planning for Altair or the Mars transfer vehicle, then return to the Dragon for entry.

The objective of BFR is to replace Dragon, Falcon 9 and FH. So it would be strange to have to rely on them.
That's not at all the only objective of BFR. And if NASA insists on a LAS, then using the already-proven F9/Dragon combo would be much cheaper than adding one to BFR.
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

Offline Robotbeat

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Re: Should the BFR have a launch escape system?
« Reply #131 on: 10/13/2017 11:37 pm »
...
The first BFR flights will not  have such a number of people that it is impossible to put in an LES. In fact I don't think you could find as many people as Elon hopes to travel to the moon, mars or LEO at the price he is offering on any regular bias. The most likely paying passenger at the moment for better or worse is going to be NASA and not private citizens.

If there are so few passengers, then they can launch and return on F9R/Dragon 2 until BFR completes hundreds of successful flights.
Bingo. And how much does, say, 300 flights cost of SpaceX gets costs as low as they want? Just $600m, less than developing a LAS.

The Dragon flights will still be very expensive. They will get lots of experience with the ship before they are ready to put people on it anyway, no need to kludge dragon in there.
We weren't saying kludge a Dragon on there, we were saying launch the Dragon on F9 and transfer crew to the BFR, just like NASA was/is planning for Altair or the Mars transfer vehicle, then return to the Dragon for entry.

The kludge is making it a part of the system, whether it is built into the rocket or not. It is impossible for BFR to be cheaper than Falcon 9 if you still have to launch a Falcon 9 (or several). They won't put people on BFR until they are comfortable launching them along with it.
The point of BFR isn't just to be cheaper than F9.

NASA has no way to get to Mars orbit, Mars surface, or Moon surface. BFR solves that. If for the first Mars trip, NASA insists on a LAS, then SpaceX will be happy to launch the crew on the reusable Falcon 9 and Dragon.

This really isn't that hard to understand.
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

Offline intrepidpursuit

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Re: Should the BFR have a launch escape system?
« Reply #132 on: 10/13/2017 11:40 pm »
If you are going to take BFR to the moon or mars then you are relying on it not to fail anyway. Adding in a Dragon, a Falcon 9, and two crew transfers isn't going to make the system appreciably safer.

NASA will either accept the BFR for human use or not. I don't see any helpful middle ground other than just using it for cargo only.

(keeps telling me the body is empty if I try reply with the quoted thread)

Offline Robotbeat

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Re: Should the BFR have a launch escape system?
« Reply #133 on: 10/13/2017 11:43 pm »
If you are going to take BFR to the moon or mars then you are relying on it not to fail anyway. Adding in a Dragon, a Falcon 9, and two crew transfers isn't going to make the system appreciably safer.

NASA will either accept the BFR for human use or not. I don't see any helpful middle ground other than just using it for cargo only.

(keeps telling me the body is empty if I try reply with the quoted thread)
Nope. NASA didn't put a LAS on Altair, but they insist on one for Orion. That contradicts your logic.
« Last Edit: 10/13/2017 11:44 pm by Robotbeat »
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

Offline pathfinder_01

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Re: Should the BFR have a launch escape system?
« Reply #134 on: 10/14/2017 06:06 am »
If you are going to take BFR to the moon or mars then you are relying on it not to fail anyway. Adding in a Dragon, a Falcon 9, and two crew transfers isn't going to make the system appreciably safer.

NASA will either accept the BFR for human use or not. I don't see any helpful middle ground other than just using it for cargo only.

(keeps telling me the body is empty if I try reply with the quoted thread)

In practice refueling on orbit with cryogens could be viewed as risky. It could be a good idea to use a dragon or specially adapted BFR(i.e. one with a LES) for a crew transfer after the BFR is fully fueled and checked out. ESP. if going to Mars(five refueling flights sounds like it could take a lot of time).

Also a Cargo BFR could be adapted to be crewed in space if it has a habitation or other module in the cargo bay with a docking port. This could be cheaper(and faster) than having to develop the crewed version and much more suitable to smaller crew sizes. It also plays well with other companies and organizations(i.e. Space X does not need to develop the payload).

That being said at the moment there is little value of a LES on the Moon or Mars(i.e. no one to rescue you should it go off) and a lot of dead weight to drag there.
« Last Edit: 10/14/2017 06:32 am by pathfinder_01 »

Offline su27k

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Re: Should the BFR have a launch escape system?
« Reply #135 on: 10/11/2018 04:56 pm »
Bump this thread due to all the BFR abort discussion triggered by the Soyuz accident, such as this:

It shows the importance of having a launch escape system. They may only ever be used on rare occasions but when they do they save a crew's life! After this, I don't think NASA will certify BFR for astronaut transport and will demand Dragon 2 be kept online for the foreseeable future.

Don't be silly. NASA isn't in the process of certifying BFS for use by NASA astronauts. And BFS was never going to replace Crew Dragon for ISS crew rotation missions. BFS is way too massive for that. The docking-loads, imparted on the aging ISS structure, alone were a showstopper for "BFS-to-ISS".

It does bring up a good point though, not having a launch abort system is a critical flaw in BFS.

I think what is missing from the discussion is that the Soyuz escape tower was already jettisoned when the abort occurred, so the spacecraft basically aborted by itself, just like BFS is supposed to do in case the BFB has an issue.

Offline ethan829

Re: Should the BFR have a launch escape system?
« Reply #136 on: 10/11/2018 06:19 pm »
I think what is missing from the discussion is that the Soyuz escape tower was already jettisoned when the abort occurred, so the spacecraft basically aborted by itself, just like BFS is supposed to do in case the BFB has an issue.

It did not:
https://twitter.com/jeff_foust/status/1050396464483115008

That said, Soyuz can use its own engines to abort if needed (and did so in 1975).

Offline TrevorMonty

Re: Should the BFR have a launch escape system?
« Reply #137 on: 10/11/2018 06:34 pm »
Bump this thread due to all the BFR abort discussion triggered by the Soyuz accident, such as this:

It shows the importance of having a launch escape system. They may only ever be used on rare occasions but when they do they save a crew's life! After this, I don't think NASA will certify BFR for astronaut transport and will demand Dragon 2 be kept online for the foreseeable future.

Don't be silly. NASA isn't in the process of certifying BFS for use by NASA astronauts. And BFS was never going to replace Crew Dragon for ISS crew rotation missions. BFS is way too massive for that. The docking-loads, imparted on the aging ISS structure, alone were a showstopper for "BFS-to-ISS".

It does bring up a good point though, not having a launch abort system is a critical flaw in BFS.

I think what is missing from the discussion is that the Soyuz escape tower was already jettisoned when the abort occurred, so the spacecraft basically aborted by itself, just like BFS is supposed to do in case the BFB has an issue.
Why people assume only 1st stage will fail on BFR, upper stage has same engines and fuel, both are capable RUD. Even in 1st stage RUD, upper stage is useless as it can't power up and boost away from exploding 1st stage in time.

Offline Patchouli

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Re: Should the BFR have a launch escape system?
« Reply #138 on: 10/11/2018 06:35 pm »

The point of BFR isn't just to be cheaper than F9.

NASA has no way to get to Mars orbit, Mars surface, or Moon surface. BFR solves that. If for the first Mars trip, NASA insists on a LAS, then SpaceX will be happy to launch the crew on the reusable Falcon 9 and Dragon.

This really isn't that hard to understand.

A stripped down BFS with a small upper stage could be used to put a Dragon into orbit.
« Last Edit: 10/11/2018 06:45 pm by Patchouli »

Offline envy887

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Re: Should the BFR have a launch escape system?
« Reply #139 on: 10/11/2018 07:26 pm »
Bump this thread due to all the BFR abort discussion triggered by the Soyuz accident, such as this:

It shows the importance of having a launch escape system. They may only ever be used on rare occasions but when they do they save a crew's life! After this, I don't think NASA will certify BFR for astronaut transport and will demand Dragon 2 be kept online for the foreseeable future.

Don't be silly. NASA isn't in the process of certifying BFS for use by NASA astronauts. And BFS was never going to replace Crew Dragon for ISS crew rotation missions. BFS is way too massive for that. The docking-loads, imparted on the aging ISS structure, alone were a showstopper for "BFS-to-ISS".

It does bring up a good point though, not having a launch abort system is a critical flaw in BFS.

I think what is missing from the discussion is that the Soyuz escape tower was already jettisoned when the abort occurred, so the spacecraft basically aborted by itself, just like BFS is supposed to do in case the BFB has an issue.
Why people assume only 1st stage will fail on BFR, upper stage has same engines and fuel, both are capable RUD. Even in 1st stage RUD, upper stage is useless as it can't power up and boost away from exploding 1st stage in time.

[citation needed]

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