I've always wondered just what is wrong with the BFS being its own LES.
Quote from: GORDAP on 09/21/2017 12:04 pmI've always wondered just what is wrong with the BFS being its own LES. Full size BFS has a propellant load higher than Falcon Heavy, even a subscale BFS would probably have propellant load higher than Falcon 9, it itself represents a danger to the crew. Remember both catastrophic failure of Falcon 9 happened on the upper stage.
I really like the idea of five 20-person escapable capsules, one on each tanker flight.
In the event of an emergency during a launch, it seems unlikely that there would be time for passengers to climb into individual escape pods and strap themselves in, and you would probably want each escape pod to hold as many people as possible for efficiency's sake. Imagine the mass and cost penalty for adding hundreds of capsules, engines, parachutes, life support and re-entry protection systems.
How about building small escape pods into the walls of the ship? They would be shaped like Soyuz or Dragon except with the engines pointing the other way. In case of danger the crew enters those pods through hatches. If something goes wrong the engines fire and they "pop" right out at an angle.These pods would have heat-shields normally facing outwards through what are structurally "windows" through the hull. They would be small, barely large enough that people can fit while strapped in. This could also work from orbit, they would just have to linger until on top of a suitable splashdown location for reentry.The problem with such a system is that it would be still quite large and require a lot of work to develop and test properly.
Once you add 10 to 20 small escape pods there will be little mass left over for cargo. It isn't practical.
Quote from: RonM on 09/26/2017 02:18 pmOnce you add 10 to 20 small escape pods there will be little mass left over for cargo. It isn't practical.Agree that it's not practical, but more likely due to complexity and cost and not mass. Soyuz and Dragon 2 mass about 1,000 kg per person, so a 100-person ITS would have 100 tonnes of escape capsules. On the 2016 ITS that leaves 200 tonnes for cargo.IMO separating the entire crew cabin would be considerably simpler, cheaper, and more reliable, if an abort system is required.
There isn't going to be any LES, over and done. Nowhere in the architecture are there detachable capsules or escape pods. Musk said repeatedly they're going for airliner level reliability and relying on redundancies.Anyone who isn't happy with that can stay home. Time to focus on other things.
An airliner is safe not because it doesn't fail, but because it has such a wide variety of intact abort modes. Not having an abort system on a crewed vessel is a show-stopper.
Quote from: Lee Jay on 10/06/2017 07:32 pmAn airliner is safe not because it doesn't fail, but because it has such a wide variety of intact abort modes. Not having an abort system on a crewed vessel is a show-stopper.It has redundancy and large safety margins but not an escape system. There’s no parachutes onboard for all passengers. Any passengers actually.