How much payload could they throw into orbit? Maybe up to half a million tonnespounds at a time.
Not with my money, I hope.
8 thoughts on “Raptor Rockets”
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How much payload could they throw into orbit? Maybe up to half a million tonnespounds at a time.
Not with my money, I hope.
Comments are closed.
That was 500 tons, not half-a-million, yes?
The 110 tons as SSTO is very interesting, if valid.
Since the point of a BFR is to avoid refueling, we can estimate the parameters of the 100 crew MCT. With refueling the MCT would be the upper stage. Without you don’t want to take along the upper stage unless you plan to use it as an artificial gravity counter mass.
Recycling water introduces calculus which I haven’t done since grade school. Since recycling lowers costs/mass I do my calculation w/o so I get some margins. 380 s. Isp is good to know. 5.7 km/s to get to mars, although that may be reduced. Trent is much better at these things than I’ll ever be. I use 2 kg of food per day per person and 6 kg of water and air. I assume packaging is included, but perhaps 10 kg total is a safer bet (from ISS data.) Volume doesn’t come into things much other than you need enough. 3 to 4 cubic meters per person for consumables seems enough for 250 days. 6 m3 of private space would be luxury along with common spaces.
Landing on mars propulsively would still require some help from the thin atmosphere so would MCT have a broad lifting body shape?
Since they aren’t going to use SLS tooling much do you think they’d sell it to Elon cheap? But would he want it?
Rand, I’m honestly curious about the meaning of your “not with my money” comment. If by that you mean you don’t want your tax dollars going to develop it, then I agree.
On the other hand, If Raptor ends up existing, I’d have absolutely no problem with, say, NASA (or any other agency) purchasing launches on it *IF* it made sound fiscal sense to do so.
May take on Raptor; *IF* they can make it reusable, and *IF* they can achieve a massive reduction in price per pound to orbit vs, say, Falcon Heavy, I think Raptor (colloquially known as the BFR) will be a success. If not, I think it’ll go the route of the Falcon 5.
I have to admit, I found the figures in the article jaw-dropping, but also an incomplete picture (probably by necessity at this point, as it’s impossible to calculate based on what’s known) due to omitting what IMHO is the most important number of all in spaceflight; payload cost per pound.
If by that you mean you don’t want your tax dollars going to develop it, then I agree.
That’s what I mean. It may be that such a vehicle makes economic sense for settlement (it is absurdly large for anything that NASA plans), and if so, then more power to Elon if he wants to fund it. As with SLS, it is not something whose development should be funded by the taxpayers.
At the very least, NASA would find the BFR every bit as useful as SLS, and that’s true even if the BFR is never built. 🙂
Elon is working on the LOX/Methane engine using full-flow combustion for fairly obvious reasons. Such engines are supposedly easy to reuse and the fuel is cheap. The engines can have high ISP and thrust-weight ratios LOX/Methane are space storable cryogenic propellants which can be stored more or less at the same temperature which simplifies the tank costs. For much the same reasons the Russians, ESA, and the Japanese at least have been looking at these kinds of engines for some time now.
I have little doubt he intends the MCT, in the long run, to be reusable and probably refueled in orbit.
But don’t expect it any soon. Falcon X or whatever it is called is what is going to happen.
That SSTO is what I find interesting. It would be a one-launch prop depot.
Stretch the tanks and make it into a tanker to refuel it as well.
My perspective is that, for the near to mid-term we don’t need anything more than the high-end Falcon Heavy (53 mt) provided that it also has a cryogenic upper stage or lander. Two of them “buddy tanked” would yield about 106 mt in LEO. A lot could be done with that capability. Further, ion propulsion is pretty mature technology. So, the cargo portion of a mission as well as some of that portion of the propellant needed beyond the Van Allen belts could be pushed beyond LEO while taking only a modest portion of that 106 tonnes. Also, if we were to focus on harvesting lunar polar ice (1:18 – ice:regolith) then we could have the shielding, propellant, and surface capability that would help lower the costs of going to Mars.