7 ms·

What about using it to cheaply send fuel from earth up into LEO? that is, take a fuel tank with some minimal set of RCS, compute and radio for remote control /

What about using it to cheaply send fuel from earth up into LEO? that is, take a fuel tank with some minimal set of RCS, compute and radio for remote control / locator beacon, and some fuel transfer / docking arrangement, and wrap it all in a disposable fairing for launch. You'd still need to send spacecraft and larger cargo up the old fashioned way, but this would allow you to neatly work around the "your only fuel is what you carry to orbit with you" problem (as long as you carry enough fuel to rendezvous with one of the fuel pods to begin with).

mlindner 5y ago
> What about using it to cheaply send fuel from earth up into LEO? Just to clarify for you here, but this can't actually launch anything directly into LEO. It needs a rocket of some sort, or something in space to "catch" it and complete the orbit. This is why what they're launching in their slingshot isn't a payload, but a small rocket with plentiful heat shielding that will contain the payload to be released. That small rocket still needs to be built every time so it doesn't actually reduce costs that much until there is something in space to "catch" the payloads. Which I am skeptical of the ability to do for Earth orbit given the much larger speed differentials of catching things in LEO. Also on the cost thing, you have the cost issue inverted and you're trying to solve the wrong problem. The most expensive part of space travel is the whole "throwing away the vehicle after one use" aspect, not the cost of the fuel. SpinLaunch makes the vehicle itself cheaper, but it's still throwing it away.
detritus 5y ago
Aye, I've been thinking these systems could be useful for hoisting dumb mass such as water in particular. Water's good for human consumption, hygiene, conversion to fuel (or ejection mass for electric motors?) and even as radiation shielding. As here on Earth, it's probably one of the most valuable 'heavy things' we need up there. it's just bloody expensive to get up there. At least until we can start lassoing asteroids... .
panick21_ 5y ago
The economics doesnt work. You still need to build a rocket and waste it. One Starship launch can reusably launch like 150tons of fuel. Compare that to 1500 SpinLaunches. There is no way for this to be even remotly economical.
TheSpiceIsLife 5y ago
This can be done with conventional rockets too, where the payload is fuel to be used by other craft. I assume there are some reasons this isn't done, like the rocket equation persisting outside of Earth's atmosphere and gravity well, ie. you still have to accelerate the fuel mass if you intend on taking it with you, but taking it from launch obviates the needed complexity to rendezvous with an orbital gas station.

mlindner 5y ago

> What about using it to cheaply send fuel from earth up into LEO? Just to clarify for you here, but this can't actually launch anything directly into LEO. It needs a rocket of some sort, or something in space to "catch" it and complete the orbit. This is why what they're launching in their slingshot isn't a payload, but a small rocket with plentiful heat shielding that will contain the payload to be released. That small rocket still needs to be built every time so it doesn't actually reduce costs that much until there is something in space to "catch" the payloads. Which I am skeptical of the ability to do for Earth orbit given the much larger speed differentials of catching things in LEO. Also on the cost thing, you have the cost issue inverted and you're trying to solve the wrong problem. The most expensive part of space travel is the whole "throwing away the vehicle after one use" aspect, not the cost of the fuel. SpinLaunch makes the vehicle itself cheaper, but it's still throwing it away.

detritus 5y ago

Aye, I've been thinking these systems could be useful for hoisting dumb mass such as water in particular. Water's good for human consumption, hygiene, conversion to fuel (or ejection mass for electric motors?) and even as radiation shielding. As here on Earth, it's probably one of the most valuable 'heavy things' we need up there. it's just bloody expensive to get up there. At least until we can start lassoing asteroids... .

panick21_ 5y ago

The economics doesnt work. You still need to build a rocket and waste it. One Starship launch can reusably launch like 150tons of fuel. Compare that to 1500 SpinLaunches. There is no way for this to be even remotly economical.

TheSpiceIsLife 5y ago

This can be done with conventional rockets too, where the payload is fuel to be used by other craft. I assume there are some reasons this isn't done, like the rocket equation persisting outside of Earth's atmosphere and gravity well, ie. you still have to accelerate the fuel mass if you intend on taking it with you, but taking it from launch obviates the needed complexity to rendezvous with an orbital gas station.