"Wet" Asteroids Could Supply Space Gas Stations 163
FleaPlus writes "Water ice was recently discovered on the large asteroid 24 Themis, and Space.com discusses proposals for producing fuel from asteroid ice. NASA and the President recently announced plans for robotic precursor missions to asteroids (and a human mission by 2025), as well as a funding boost for R&D to develop techniques like in-situ resource utilization. Since most of the mass of a beyond-Earth mission is fuel, refueling in orbit would be a huge mass- and cost-saver for space exploration (especially if fuel can be produced in space), but a large unknown is how to effectively extract water in an environment lacking gravity."
Re:Mining Asteroids like Eve Online (Score:5, Informative)
if landing on an asteroid is difficult at best*, and the chances of the asteroid moving in the direction of your ship's travels are slim to none
Why do you assume either of these? Asteroids are orbiting the sun. Their orbits are predictable, modulo some minor variations caused by the (very weak) gravity of nearby ones. It's much easier than, for example, landing on an aircraft carrier, where you have to worry about changes in the wind.
As to the probability of them travelling in the same direction, it's pretty much guaranteed. If you're going from the Earth to the asteroids, you use a transfer orbit, where you are starting in the Earth's orbit around the sun and then injecting enough energy to move you out to the asteroid belt. You end up on solar orbit in the asteroid belt. Any asteroid in the same orbit will, by definition, be going in the same direction and speed as you. Asteroids in nearby orbits will have a small relative speed, and the energy required to enter a transfer orbit to rendezvous with them is relatively small.
Re:Mostly laughable concept. (Score:2, Informative)
For example, to break up water into Hydrogen and Oxygen, you can use
...solar radiation, which costs you nothing, and the interesting parts of which can be gathered with a large mylar-bag mirror.
The rest of your comment was dumb after I changed this part, so I ignored it.
Re:Mostly laughable concept. (Score:3, Informative)
Multiple citations needed.
I don't know where you pulled those numbers out of, but they're completely wrong. Depending on the process used electrolysis can have an efficiency rating of 30%-60%. Nuclear reactors are much better than 20% efficient, unless you think an RTG is a nuclear reactor. Solar thermal power is a better bet for generating large amounts of power for running a space factory. No fuel needed and a few square kilometers of mylar will set it up nicely.
Re:Water for Life, Nuclear for Fuel (Score:4, Informative)
Basically, no.
In somewhat more detail, slightly. Reactor coolant tends to get radioactive after a while. But a nuclear rocket doesn't have any particular part of the coolant present for "a while", since it goes in one end and out the other without any potentially embarrassing recirc.
So, in general, if you used H2 as the reaction mass for your reactor, you could expect some non-radioactive deuterium moderately (which is a joke, in case you didn't get it) regularly, and an atom or so of tritium now and then.
If you used water, the same plus some O-17 and less often O-18.
Note that the amount of radioactive H@ (and O2) will be dependent on the reactor design. Some neutrons are easier to capture than others....
Re:One step at a time.. (Score:3, Informative)
> I mean hell, the morons in Washington can't even decide if we should build any kind of space ship.
I'm not aware of any substantial argument over whether we should build a "space ship" period, but the current spaceship argument divides up into three parts with multiple options each: crew launcher, crew spacecraft/capsule, and super-heavy cargo launcher:
crew launcher
* Ares I: the plan since 2008, set to be ready by 2017-2019 at a cost of $15-$45 billion (depending whose estimate you use). It's a liquid stage sitting on top of a Shuttle solid rocket booster. Has some safety issues due to the giant solid rocket stage it's sitting on, such as vibration/oscillation and inability of a crew capsule to escape a solid propellant explosion without its parachute melt.
* commercial crew providers: rockets like the Delta IV and Atlas V (40 successful launches in a row so far), plus newer rockets like the Falcon 9. Expected cost of a $0.5-$2 billion per provider with goal of multiple competitors, with expected crew capability from the first providers in 2014-2015.
* DIRECT/inline Shuttle-Derived: several billion dollars development cost (not sure of exact number off-hand) plus cost of maintaining shuttle infrastructure, with predicted crew capability 2013-2015
Crew spacecraft/capsules
* Orion: Has been under development since 2008, originally designed to be lifted on Ares I which is taking forever, but if another launcher were available could supposedly launch crew by 2013-2014; development cost $10B or so (don't have numbers handy). Somewhat oversized with a high per-launch cost, current plan is to re-adapt it as an ISS rescue vehicle (with option for future adaptation into beyond-Earth spacecraft) and use commercial crew instead
* commercial crew: multiple capsules with various designs, such as Boeing/Bigelow Orion Lite, Sierra Nevada Dream Chaser (winged craft), SpaceX Dragon, and Blue Origin capsule. Development cost of $1B-$2B each, with initial crew capability by 2014-2015.
super-heavy cargo vehicle (what's often described as a heavy-lift vehicle/HLV):
* Ares V: Currently scheduled to start development in 2017 with initial launch in late 2020s, at a cost of many billions of dollars.
* DIRECT Jupiter variants: less expensive than Ares V
* EELV-derived heavy-lift: based on existing EELV rockets, development cost of a few billion and low fixed annual costs (since you already have EELV rockets launching), although it's more difficult to get this up to the payloads offered by Atlas V and DIRECT
* no HLV or minimal EELV-based HLV: Bringing this back onto the topic, if you make use of in-space refueling (supplied either by terrestrial launches or asteroids, as mentioned in submission article) and in-space assembly, you can eliminate the need for a big HLV. This also ensures a high launch rate, allowing for economies of scale. Refueling orbital depots also provides a market for unproven launchers, encouraging more experimentation with new types of launchers.
The status quo for the past several years is Ares I + Orion. The new plan announced by NASA and the President is commercial launchers, commercial crew spacecraft, and a decision on an HLV in 2015. I personally favor commercial launchers, commercial crew, and no HLV with an emphasis instead of in-space refueling.