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You claim “ There's a large class of space flight problems you can't giant rocket your way out of.” …but every single one of your examples is wrong and proves t
by Robotbeat 5y ago
You claim “ There's a large class of space flight problems you can't giant rocket your way out of.”
…but every single one of your examples is wrong and proves the point that large rocket DOES solve it.
For example:
> The closest they come to closed-loop anything is 93% re-use of water; a Mars mission (by NASA estimates) would need 99%+.
Oh, really? Why precisely do you think NASA estimated 99%+ water recycling would be required? Because MASS.
>trace volatiles
In fact, ISS has had trace volatiles measured in real-time for years: https://ntrs.nasa.gov/citations/20070030106 https://ntrs.nasa.gov/citations/20070030106
ISS sends samples back to validate the instrument because ISS is a testbed. It isn’t absolutely required.
> there's no food that stays edible for five years
Wrong. Anything will stay edible for 5 years if put in a deep freezer. And canned food lasts a LOT longer than that. “Oh, it’s not as yummy and the nutrient profile changes”, well sure. It’s nice to have fresh food. But the claim no food stays edible for 5 years is trivially false. All of us have eaten food that old, and the radiation environment isn’t enough to change that equation massively.
ISS can withstand long periods without resupply, and has done so when there has been launch failures. If you can prepare for it ahead of time, it’s just a matter of having a sufficient spare pool on-orbit instead of just having the spare pool on Earth. In other words, MASS.
Waste management is annoying if you don’t have canisters to place the waste in, but again, that’s also just MASS. You can put the waste in double sealed containers and then just place it outside the airlock. Can do that on orbit, so that’s actually one advantage Mars has over ISS.
And I don’t see why Mars can’t have a full time ground crew, too. Time delay annoying but not in any way a showstopper.
In fact, a large rocket solves these problems so completely, people who should know better still haven’t wrapped their heads around just how completely it changes the situation. The water recycling thing you repeated is illustrative of this. It literally is just mass.
- avmich 5y agoSpace-specific problems are: 1) weightlessness - but people can deal with that, and if needed, I'm sure centrifuges can help; 2) radiation - but large shields can alleviate this problem; 3) space debris, attacking with large speeds - but we can use radars, shields, plasma clouds to reduce problems from this. With all of these problems large rockets do help.
- Robotbeat 5y agoSpace debris is a much worse problem in LEO than anywhere else from here to Mars. Mars’ surface itself at likely landing sites is shielded from all micrometeorites by the atmosphere which burns them up or slows them down to a reasonable terminal velocity (low for micrometeorites, even in the thin Martian atmosphere).
- idlewords 5y agoA centrifuge solves microgravity problems, but no one has ever flown one at human sizes. Seems like a big to-do list item. With cosmic rays, having a large mass of metal around you will actually increase your dose (because of secondary radiation). So you need to figure out shielding that helps more than it hurts. Space is hard.
- avmich 5y agoLarge rockets still help, even if shielding is not straightforward though.
- idlewords 5y agoCertainly. And if we had a big enough rocket, we could put its fins on earth and the tip on Mars and just climb up the middle.
- avmich 5y agoThat all skips the interesting middle values of the problem parameters :) . Seriously, for long time already it's not a rocket science. Existing technologies - with engineering efforts - are capable to bring humans to any point between Mercury and asteroids. We'll likely develop something better, and Solar system would be all reachable without major breakthroughs. Certainly not of the kind "rocket fins on Earth, tip on Mars".
- Robotbeat 5y agoShielding ESPECIALLY is straightforward, though. The parent was wrong about it being hard.
- idlewords 5y agoI wish you'd read your own links. The machine that measures volatiles on ISS works against a target list of 20 or so compounds. This is an excellent solution as long as your compound of interest is on the list. But when it's not (like when siloxanes turned out to be a big problem for catalyst bed poisoning) then you are entirely dependent on an earth lab. Here's the Journal of Nutrition saying that five-year stable food adequate for space flight doesn't exist: https://academic.oup.com/jn/article/150/9/2242/5870322 https://academic.oup.com/jn/article/150/9/2242/5870322. You should write them with the good news that this is trivially solved. These arguments about "everything is trivial with big enough rockets" remind me a lot of trying to have a discussion with blockchain people. Yes, if you have a warp drive, you can resupply Martian astronauts daily with fresh foods. But maybe let's see it in action before we call it a solved problem.
- Robotbeat 5y ago5 year NON-FROZEN food “adequate for Spaceflight”doesn’t exist. But if you simply bring a big freezer, the problem is almost trivial. Why don’t they normally do that on ISS already? Fundamentally, MASS. Freezers are heavy (mass) and use a lot of power (mass). Fun fact, but SpaceX has launched ice cream in a freezer to ISS before. This isn’t hypothetical. See how many hidden assumptions there are which can be relaxed if mass constraints are relaxed? It’s just assumed freezers aren’t viable because they’re too heavy. There’s stuff like this all over the place. The entire field is built under the assumption that mass is extremely rare. Thanks for highlighting the point that big rocket solves these problems in almost a trivial way. (And what does blockchain have to do with it? Blockchain is simply a worse solution to a database problem.)