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How to make the food and water Mars-bound astronauts will need for their mission:
If we ever intend to send crewed missions to deep-space locations, then we need to come up with solutions for keeping the crews supplied. For astronauts aboard the International Space Station (ISS), who regularly receive resupply missions from Earth, this is not an issue. But for missions traveling to destinations like Mars and beyond, self-sufficiency is the name of the game.
This is the idea behind projects like BIOWYSE and TIME SCALE, which are being developed by the Centre for Interdisciplinary Research in Space (CIRiS) in Norway. These two systems are all about providing astronauts with a sustainable and renewable supply of drinking water and plant food. In so doing, they address two of the most important needs of humans performing long-duration missions that will take them far from home.
[...] In short, the ISS relies on costly resupply missions to provide 20% of its water and all of its food. But if and when astronauts establish outposts on the moon and Mars, this may not be an option. While sending supplies to the moon can be done in three days, the need to do so regularly will make the cost of sending food and water prohibitive. Meanwhile, it takes eight months for spacecraft to reach Mars, which is totally impractical.
So it is little wonder that the proposed mission architectures for the moon and Mars include in-situ resource utilization (ISRU), in which astronauts will use local resources to be as self-sufficient as possible. Ice on the lunar and Martian surfaces, a prime example, will be harvested to provide drinking and irrigation water. But missions to deep-space locations will not have this option while they are in transit.
[...] Technologies like these will be crucial when it comes time to establish a human presence on the moon, on Mars, and for the sake of deep-space missions. In the coming years, NASA plans to make the long-awaited return to the moon with Project Artemis, which will be the first step in the creation of what they envision as a program for "sustainable lunar exploration."
(Score: 2) by Immerman on Thursday June 04 2020, @01:43PM
Who said anything about a single ship? You send several, with essential and non-essential supplies distributed between them.
But then, if you're getting ready to send passengers (or have already done so) then you've probably pretty much mastered the whole landing safely thing so it's not such a big deal.
And as cheap as Starship is looking to cost, it's a pretty good bet that most of the ships you send aren't coming back - the steel would be useful on Mars, and the energy budget to refuel the thing could be better spent on Mars for other purposes. Especially if you send cargo in "flight-tested" ships that are reaching the end of their service life anyway - send them on a last hurrah to Mars. You only need to send back ships when you have passengers to return. And maybe the occasional ship full of engines salvaged from other ships - I think I've heard estimates to build the rest of the Starship are about $10M, while the engines themselves are about $5M each.
Ion engines are indeed promissing, and something like an "orbital tugboat" could be very valuable - perhaps something like an ion-drive "SuperHeavy" alternative that could mate to the base of a Starship (or some sort of cargo module) and push it between planets. Unfortunately at present I don't think we have anything particularly suitable for moving Starship-sized payloads, at least not unless we're okay with the trip taking many years. Which could be fine for some supplies, but there's a lot of stuff that would suffer from years of intense interplanetary radiation.
They're also (currently) basically useless as an alternative for aerobraking - even powered by a MW nuclear reactor their maximum thrust amounts to a rounding error compared to aerobraking. Once you're no longer in microgravity you need lots of raw power, and ion drives suck at that. Same issue if you use chemical engines for most of the impulse - the ion drives will take years to do what the chemical rockets do in minutes, and given how incredibly expensive they are to build they're probably not worth using except where they're the primary means of propulsion. But when transit time isn't a consideration they can really shine.