How NASA Will Use Robots To Create Rocket Fuel From Martian Soil (ieee.org)

Engineers are building a prototype of a robotic factory that will create water, oxygen, and fuel on the surface of Mars. From a report: The year is 2038. After 18 months living and working on the surface of Mars, a crew of six explorers boards a deep-space transport rocket and leaves for Earth. No humans are staying behind, but work goes on without them: Autonomous robots will keep running a mining and chemical-synthesis plant they'd started years before this first crewed mission ever set foot on the planet. The plant produces water, oxygen, and rocket fuel using local resources, and it will methodically build up all the necessary supplies for the next Mars mission, set to arrive in another two years. This robot factory isn't science fiction: It's being developed jointly by multiple teams across NASA. One of them is the Swamp Works Lab at NASA's John F. Kennedy Space Center, in Florida, where I am a team lead. Officially, it's known as an in situ resource utilization (ISRU) system, but we like to call it a dust-to-thrust factory, because it turns simple dust into rocket fuel. This technology will one day allow humans to live and work on Mars -- and return to Earth to tell the story.

But why synthesize stuff on Mars instead of just shipping it there from Earth? NASA invokes the "gear-ratio problem." By some estimates, to ship a single kilogram of fuel from Earth to Mars, today's rockets need to burn 225 kilograms of fuel in transit -- launching into low Earth orbit, shooting off toward Mars, slowing down to get into Mars orbit, and finally slowing to a safe landing on the surface of Mars. We'd start with 226 kg and end with 1 kg, which makes for a 226:1 gear ratio. And the ratio stays the same no matter what we ship. We would need 225 tons of fuel to send a ton of water, a ton of oxygen, or a ton of machinery. The only way to get around that harsh arithmetic is by making our water, oxygen, and fuel on-site. Different research and engineering groups at NASA have been working on different parts of this problem. More recently, our Swamp Works team began integrating many separate working modules in order to demonstrate the entire closed-loop system. It's still just a prototype, but it shows all the pieces that are necessary to make our dust-to-thrust factory a reality. And although the long-term plan is going to Mars, as an intermediate step NASA is focusing its attention on the moon. Most of the equipment will be tried out and fine-tuned on the lunar surface first, helping to reduce the risk over sending it all straight to Mars.

Comments

Simply no other way....

[ColaMan]

We'd start with 226 kg and end with 1 kg, which makes for a 226:1 gear ratio. And the ratio stays the same no matter what we ship. We would need 225 tons of fuel to send a ton of water, a ton of oxygen, or a ton of machinery. The only way to get around that harsh arithmetic is by making our water, oxygen, and fuel on-site

Or refuel on-orbit, which is SpaceX's thoughts on the matter, because 90% of that fuel is needed to get you 150km up out of Earth's gravity well. Or..... just could develop more efficient engines. Or make bigger ion thrusters, a reactor that can deliver 1MW continuously, send all the supplies on the slow trip to Mars with the ion engines, send the people on the quick one with the chemical rockets, etc, etc.

No, but the only way around the problem is to develop tricky automated mining equipment and make all that stuff once you get there. I work with mining equipment. Maintenance intervals (oils/filters/etc) are every 50 hours of operation, machine-stopping breakdowns occur every few hundred hours, large component changeout (pumps, hydraulic cylinders, etc) is 4000 hours. 4000 hours is a year of operation at a 50% duty cycle. So you're going to ship all this stuff to Mars, and then expect it to run, continuously digging stuff up and crushing it and heating it and so on and so forth, for a couple of years? In a cold, dusty, zero-maintenance environment?

I know, I know, we're going to need mining equipment on Mars for stuff. Just send someone willing to stay a few extra years. And a whole lot of spare parts.

Re:With what???

[Kjella]

Oh look, NASA engineers are playing in the dirt. They might as well practice mining for gold in finely shredded cash. [Long rant about SLS and Orion]

Well then why are you trash talking the engineers that are actually doing what NASA should be doing? An ISRU factory for Mars is exactly the kind of unique, never been done before experiment with no obvious commercial potential that they should be working on, whether it's delivered via the SLS/Orion or BFR/BFS. I know SpaceX envisioned some day refueling their rockets on Mars but to my knowledge they haven't released as much as a sketch indicating they've seriously worked on it. With the R&D challenges they have with the BFR and the difficulty they have finding funding for it I'd be very surprised if they've done anything at all.