An interesting new concept: “optical” mining of water in orbit.
14 thoughts on “ISRU”
An actual mission to a 1000-ton asteroid to retrieve 100 tons of ice to high Earth or lunar orbit, he says, would cost a few hundred million dollars.
Or you could launch 50 ton of ready to go fuel for $100m on a FH.
Best case would be to find rocks at a Lagrange point about 1 km/s away. How much of that recovered methane/oxygen would be needed to retrieve it?
Futzing around with a delta V calculator it seems you’d use up 95% of the retrieved fuel to get it. If the delta V requirement is higher it’s not even marginal. I was using 100 ton of dry mass and 300 Isp.
I’d be interested in what others calculate?
Growth in Earth-sourced costs for each ton of ice beyond the first 1,000 is sublinear, however. Cost of FH-launched propellant will rapidly outpace the ISRU pipeline.
I would calculate it with an Isp of 10,000 seconds.
Ok, but that fuel (not methane/oxygen) would require another 11 km/s to LEO?
It depends.
Mmm.. If you’re using those sorts of thrusters, is this the appropriate fuel to be mining?
The propellant is a payload for a different kind of rocket. No rush to move propellant; slow boats are fine, just as they are for oil.
Early proposals for asteroid resource material used mass drivers, in order to use whatever was *not* wanted to propel home what *was* wanted. Apparently this is not being used in this proposal??????
“Other people have talked and written about bagging asteroids and pumping in highly-concentrated sunlight to get the water out,” Joel Sercel, founder and chief engineer of the southern Calif.-based TransAstra Corporation, told me. But he says he figured out that you can use that sunlight to either break up the whole asteroid in the bag; or to dig holes in controlled ways to excavate the water and carbon dioxide.
He’s right that bagging and cooking the water out of asteroids isn’t a new idea – even I’ve come up with the idea independently, I would have thought that breaking up most asteroids with a high volatile content would happen when the heat is applied whether or not that’s the intent.
I’m a bit doubtful that many NEO’s would have all that much water in them, as their a bit close to the Sun.
Yeah I have heard of the idea of mining asteroid ice for propulsion several times. Cannot remember the first time I heard of it. But there is even an Isaac Asimov short story with it as a plot element: https://en.wikipedia.org/wiki/The_Martian_Way
I don’t remember the author, but there was a short story about a guy drifting off in space to his death until he decided to use beer from storage as propellant!
I couldn’t read it, because I use an ad blocker. Any more, trying to “surf” the internets without one is more like a swim race through cold molasses. It takes up to 5 minutes to load a single page of National Review, so I don’t read it any more. And even Drudge sucks. It updates just as I am trying to click on something, and the link shifts elsewhere. We’ve regressed to the era of the original modem version of AOL.
Network bandwidth isn’t as much of a problem for me as the memory and CPU load some web pages put on my computer. But the solution is the same, deny the problem content.
There always seems to be an underpants gnome think going on with stories like this. The idea is to capture an asteroid, wrap it up, and then stage three everything is separated and stored.
An actual mission to a 1000-ton asteroid to retrieve 100 tons of ice to high Earth or lunar orbit, he says, would cost a few hundred million dollars.
Or you could launch 50 ton of ready to go fuel for $100m on a FH.
Best case would be to find rocks at a Lagrange point about 1 km/s away. How much of that recovered methane/oxygen would be needed to retrieve it?
Futzing around with a delta V calculator it seems you’d use up 95% of the retrieved fuel to get it. If the delta V requirement is higher it’s not even marginal. I was using 100 ton of dry mass and 300 Isp.
I’d be interested in what others calculate?
Growth in Earth-sourced costs for each ton of ice beyond the first 1,000 is sublinear, however. Cost of FH-launched propellant will rapidly outpace the ISRU pipeline.
I would calculate it with an Isp of 10,000 seconds.
Ok, but that fuel (not methane/oxygen) would require another 11 km/s to LEO?
It depends.
Mmm.. If you’re using those sorts of thrusters, is this the appropriate fuel to be mining?
The propellant is a payload for a different kind of rocket. No rush to move propellant; slow boats are fine, just as they are for oil.
Early proposals for asteroid resource material used mass drivers, in order to use whatever was *not* wanted to propel home what *was* wanted. Apparently this is not being used in this proposal??????
“Other people have talked and written about bagging asteroids and pumping in highly-concentrated sunlight to get the water out,” Joel Sercel, founder and chief engineer of the southern Calif.-based TransAstra Corporation, told me. But he says he figured out that you can use that sunlight to either break up the whole asteroid in the bag; or to dig holes in controlled ways to excavate the water and carbon dioxide.
He’s right that bagging and cooking the water out of asteroids isn’t a new idea – even I’ve come up with the idea independently, I would have thought that breaking up most asteroids with a high volatile content would happen when the heat is applied whether or not that’s the intent.
I’m a bit doubtful that many NEO’s would have all that much water in them, as their a bit close to the Sun.
Yeah I have heard of the idea of mining asteroid ice for propulsion several times. Cannot remember the first time I heard of it. But there is even an Isaac Asimov short story with it as a plot element:
https://en.wikipedia.org/wiki/The_Martian_Way
I don’t remember the author, but there was a short story about a guy drifting off in space to his death until he decided to use beer from storage as propellant!
I couldn’t read it, because I use an ad blocker. Any more, trying to “surf” the internets without one is more like a swim race through cold molasses. It takes up to 5 minutes to load a single page of National Review, so I don’t read it any more. And even Drudge sucks. It updates just as I am trying to click on something, and the link shifts elsewhere. We’ve regressed to the era of the original modem version of AOL.
Network bandwidth isn’t as much of a problem for me as the memory and CPU load some web pages put on my computer. But the solution is the same, deny the problem content.
There always seems to be an underpants gnome think going on with stories like this. The idea is to capture an asteroid, wrap it up, and then stage three everything is separated and stored.