5 ms·

A follow-up question to that would be - how much $$ do you save per launch by reusing the first stage?

by dmoy 11y ago

jacquesm 11y ago
http://www.space.com/21386-spacex-reusable-rockets-cost.html http://www.space.com/21386-spacex-reusable-rockets-cost.html ~75%.
- bryanh 11y ago
  The money quote: > Musk said that a rocket's first stage accounts for three-quarters of its total price tag, so a vehicle with a reusable first stage can be produced at far less cost — assuming the hardware is fully and rapidly reusable. ~75% savings seems like a "best case scenario" number.
  - jacquesm 11y ago
    Good enough for me. Even if it is only 25% in practice they'll own the market.
    - mikeash 11y ago
      They're already insanely cheap compared to most competitors. This should take them to being ludicrously cheap.
      - jacquesm 11y ago
        Let's see who tries to imitate them and do a re-use, some real competition is what's needed next. Now for second stage re-use ;)
        TeMPOraL 11y ago
        And then for the crew capsule reuse... oh wait :). Seriously though, now I'm just waiting for updates on BFR / Mars mission development progress.
        mikeash 11y ago
        I think SpaceX is sufficiently motivated by their man at the top that they'll keep doing great things even in the total absence of competition. But it would still be great to see others go this way, to see different approaches tried and such. It sounds like some other launchers were looking at reusability plans before (Ariane had plans for some wacky thing that would fly back just the engines) but now that it's been demonstrated to work I imagine it will become much more serious.
        Tossrock 11y ago
        ULA is already trying to imitate them with their announced 'Vulcan' concept, where the engines eject and parachute back, but that's (many) years away from actually happening.
  - escape_goat 11y ago
    If I understand correctly, even if they can only reuse the rocket motors, that would still be most of the 75% figure.
    - __d 11y ago
      Aside from the cost savings, the other goal of reusing boosters is to reduce the time between launches. The challenge for SpaceX is to inspect the booster, integrate a new second stage & payload, and relaunch in a few weeks. With a few years of work, it should be almost like a cargo jet turnaround. ULA's Vulcan plan is to parachute the engines and pumps back, catch the rope with a helicopter, inspect and reattach to a new set of tanks. That seems likely to be a little more complex to me.
      - lmm 11y ago
        The catching with a helicopter part is complex, but not time-consuming - either it works or it doesn't. The rest is probably if anything easier - I'd imagine SpaceX will have to tear down the booster entirely for inspection, at least for the first few hundred. These things are (or will be) built to be disassembled and reassembled, attaching engines and pumps to a new tank is not going to be a long and complex process.
  - simonh 11y ago
    The other important factor is how many times you get to re-use the stage, because that tells you the saving per launch. If you get to re-use it once, then on each flight you save 37.5% of the launch cost. If you re-use it again twice (3 launches of the first stage) you save 50% of the launch cost per flight (each flight costs you 1/3 of the first stage cost). And so on. That's not factoring in refurb and re-fueling costs, of course.
InclinedPlane 11y ago
Lots. There's really not a lot of costs that can add up for reuse of these stages. It'll require a bit of cleaning up, a few new bits and pieces replaced and added, and a lot of inspection work. But most of the cost of the stage is in manufacturing the engines and tanks, so it should add up to enormous savings, even if it's relatively costly to reuse each stage compared to the theoretical limits. Edit: the flip-side is that the reliability and robustness improvements from reusability may be as big a win as cost. Currently it costs tens of millions of dollars to launch a rocket to orbit, which means it's almost never done except as part of a paid launch. Moreover, despite the seemingly high number of launches very few of those launches represent expanding the test-envelope much, every single launch is typically straight down the middle of the performance envelope, to maximize the chance of success. That results in learning very little about these vehicles despite how much they've been flown. By introducing reuse and dropping the cost of flight it may become possible to do real test programs, which would make it possible to determine the flight envelope characteristics of vehicles and help lead to improving designs over time.
- jacquesm 11y ago
  And with the amount of redundancy built in they might even go with 'acceptable loss' in terms of engines that cut out early in flight. Which makes you wonder how many engines they could lose and still complete a mission.
  - mikeash 11y ago
    Falcon 9 is designed to withstand losing one engine and still make it to orbit. Reusability makes it more interesting. There's a lot of extra fuel on board now which could be used to make up for lost engines if you're willing to throw away the first stage.
- twistedpair 11y ago
  Good point. Orbcomm already paid off the booster. Now SpaceX can take it up for a joy ride for only a few hundred grand of gas and really fly the fins off it. I bet they relaunch this booster on their own dime as a demo.
gozur88 11y ago
Depends on the procedure they ultimately decided to use for the prep. Originally the the shuttle main engines had to be taken apart, with every part inspected before the next launch. If they have to do something like that there's not much point. But if they can get it to point where it's a matter of gassing it up for the next flight, that's a huge savings. Fuel is a few hundred grand for a rocket that costs sixty million dollars. It's nothing, basically.
- mikeash 11y ago
  Hopefully it won't be anything like the Shuttle. The Shuttle was bleeding edge in a dozen different ways. The engines were extremely high performance and that made them fragile. SpaceX seems to build things a lot more low-key. They don't use fancy propellants, their engines aren't particularly efficient, and overall they seem to go more for robustness and simplicity. (Simplicity doesn't really apply for a crazy-ass landing scheme. But aside from that....) Obviously it remains to be seen, but I think it's likely to be a lot more gas-and-go than the Shuttle.
  - gozur88 11y ago
    Yes, I expect you're right about that, and furthermore I expect SpaceX will be willing to make substantial design changes in support of that effort.

A follow-up question to that would be - how much $$ do you save per launch by reusing the first stage?

by dmoy 11y ago

A follow-up question to that would be - how much $$ do you save per launch by reusing the first stage?

http://www.space.com/21386-spacex-reusable-rockets-cost.html http://www.space.com/21386-spacex-reusable-rockets-cost.html ~75%.

bryanh 11y ago
The money quote: > Musk said that a rocket's first stage accounts for three-quarters of its total price tag, so a vehicle with a reusable first stage can be produced at far less cost — assuming the hardware is fully and rapidly reusable. ~75% savings seems like a "best case scenario" number.
- jacquesm 11y ago
  Good enough for me. Even if it is only 25% in practice they'll own the market.
  - mikeash 11y ago
    They're already insanely cheap compared to most competitors. This should take them to being ludicrously cheap.
    - jacquesm 11y ago
      Let's see who tries to imitate them and do a re-use, some real competition is what's needed next. Now for second stage re-use ;)
      - TeMPOraL 11y ago
        And then for the crew capsule reuse... oh wait :). Seriously though, now I'm just waiting for updates on BFR / Mars mission development progress.
      - mikeash 11y ago
        I think SpaceX is sufficiently motivated by their man at the top that they'll keep doing great things even in the total absence of competition. But it would still be great to see others go this way, to see different approaches tried and such. It sounds like some other launchers were looking at reusability plans before (Ariane had plans for some wacky thing that would fly back just the engines) but now that it's been demonstrated to work I imagine it will become much more serious.
      - Tossrock 11y ago
        ULA is already trying to imitate them with their announced 'Vulcan' concept, where the engines eject and parachute back, but that's (many) years away from actually happening.
- escape_goat 11y ago
  If I understand correctly, even if they can only reuse the rocket motors, that would still be most of the 75% figure.
  - __d 11y ago
    Aside from the cost savings, the other goal of reusing boosters is to reduce the time between launches. The challenge for SpaceX is to inspect the booster, integrate a new second stage & payload, and relaunch in a few weeks. With a few years of work, it should be almost like a cargo jet turnaround. ULA's Vulcan plan is to parachute the engines and pumps back, catch the rope with a helicopter, inspect and reattach to a new set of tanks. That seems likely to be a little more complex to me.
    - lmm 11y ago
      The catching with a helicopter part is complex, but not time-consuming - either it works or it doesn't. The rest is probably if anything easier - I'd imagine SpaceX will have to tear down the booster entirely for inspection, at least for the first few hundred. These things are (or will be) built to be disassembled and reassembled, attaching engines and pumps to a new tank is not going to be a long and complex process.
- simonh 11y ago
  The other important factor is how many times you get to re-use the stage, because that tells you the saving per launch. If you get to re-use it once, then on each flight you save 37.5% of the launch cost. If you re-use it again twice (3 launches of the first stage) you save 50% of the launch cost per flight (each flight costs you 1/3 of the first stage cost). And so on. That's not factoring in refurb and re-fueling costs, of course.

InclinedPlane 11y ago

Lots. There's really not a lot of costs that can add up for reuse of these stages. It'll require a bit of cleaning up, a few new bits and pieces replaced and added, and a lot of inspection work. But most of the cost of the stage is in manufacturing the engines and tanks, so it should add up to enormous savings, even if it's relatively costly to reuse each stage compared to the theoretical limits. Edit: the flip-side is that the reliability and robustness improvements from reusability may be as big a win as cost. Currently it costs tens of millions of dollars to launch a rocket to orbit, which means it's almost never done except as part of a paid launch. Moreover, despite the seemingly high number of launches very few of those launches represent expanding the test-envelope much, every single launch is typically straight down the middle of the performance envelope, to maximize the chance of success. That results in learning very little about these vehicles despite how much they've been flown. By introducing reuse and dropping the cost of flight it may become possible to do real test programs, which would make it possible to determine the flight envelope characteristics of vehicles and help lead to improving designs over time.

jacquesm 11y ago
And with the amount of redundancy built in they might even go with 'acceptable loss' in terms of engines that cut out early in flight. Which makes you wonder how many engines they could lose and still complete a mission.
- mikeash 11y ago
  Falcon 9 is designed to withstand losing one engine and still make it to orbit. Reusability makes it more interesting. There's a lot of extra fuel on board now which could be used to make up for lost engines if you're willing to throw away the first stage.
twistedpair 11y ago
Good point. Orbcomm already paid off the booster. Now SpaceX can take it up for a joy ride for only a few hundred grand of gas and really fly the fins off it. I bet they relaunch this booster on their own dime as a demo.

gozur88 11y ago

Depends on the procedure they ultimately decided to use for the prep. Originally the the shuttle main engines had to be taken apart, with every part inspected before the next launch. If they have to do something like that there's not much point. But if they can get it to point where it's a matter of gassing it up for the next flight, that's a huge savings. Fuel is a few hundred grand for a rocket that costs sixty million dollars. It's nothing, basically.

mikeash 11y ago
Hopefully it won't be anything like the Shuttle. The Shuttle was bleeding edge in a dozen different ways. The engines were extremely high performance and that made them fragile. SpaceX seems to build things a lot more low-key. They don't use fancy propellants, their engines aren't particularly efficient, and overall they seem to go more for robustness and simplicity. (Simplicity doesn't really apply for a crazy-ass landing scheme. But aside from that....) Obviously it remains to be seen, but I think it's likely to be a lot more gas-and-go than the Shuttle.
- gozur88 11y ago
  Yes, I expect you're right about that, and furthermore I expect SpaceX will be willing to make substantial design changes in support of that effort.