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Full Version: Nasa can't send humans to Mars until it gets the food right
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The complexity of growing food and ensuring a sufficiently healthy and diverse diet is often overlooked in popular science/culture when it comes to long term space missions. Contrary to common myth you can't just grow a vat of algae and keep the astronauts permanently healthy on a mono-diet.
No, NASA can't send humans to Mars because it doesn't have the money.

That's it really, their budget is so small and so tied up in useless projects (SLS I'm looking at you), that they can't possibly perform as they once did.


Which is also case with many other organisations, both international (ITER) and national (infrastructure).
(03-27-2018, 10:58 PM)Dalex Wrote: [ -> ]No, NASA can't send humans to Mars because it doesn't have the money.

They're not mutually exclusive. Throwing more money at NASA would still mean they'd have to figure all this out.
Greg Matloff has been looking at Mars missions recently. He thinks some sort of Environmental Control and Life Support System (ECLSS) that allows recycling is necessary for any mission of this duration.
https://www.centauri-dreams.org/2018/03/...con-heavy/
Quote:If partial recycling were not built in to the mission, a two-person crew could not be supported in the proposed spacecraft for missions of one year or longer. Projections from International Space Station technology indicate that a near-term goal for water recycling is 85% and the oxygen recovery rate can be raised to 75% [11,12]. Applying these values for an interplanetary mission applying near-term recycling technology, the daily consumable requirement per astronaut is 0.21 kg oxygen, 0.62 kg food, and 0.53 kg of water. Each crew member consumes about 1.4 kg per day of these resources or about 500 kg per year. A 4-person crew therefore requires about 2,000 kg of these resources for a 360-day duration interplanetary voyage.
It is next necessary to estimate the mass of the Environmental Control and Life Support System (ECLSS) equipment, not including consumables, necessary to support the mission. In Table 4.3 of his monograph, Rapp estimates the mass of the water-recovery system for a 180-day transit to Mars at 1.4 metric tons or 1,400 kg and the mass of the oxygen recovery system at 0.5 metric tons or 500 kg for a 6-person crew [13]. We are here considering a smaller crew and the 180-day return voyage as well as the 180-day flight to the interplanetary destination. Since we have no idea regarding ECLSS reliability on a deep-space mission, we will assume here that the required mass of ECLSS equipment is 3,000 kg. Including the 2,000 kg requirement for oxygen, food and water, the total ECLSS mass is about 5,000 kg.

Note that another subject of that article is sails, which Matloff thinks are necessary to assist propulsion; looks like the sail concept could become a vital part of interplanetary travel in the medium term, just as we expect at OA.
To put it another way, a mission to Mars won't be ready to go anywhere until ECLSS recycling technology is a lot better than it is now. Water and oxygen will need to be reclaimed, and the water could be used to reconstitute dried food (I doubt that they'd be able to grow much food, if any, on the earliest missions, although that would be necessary on later and longer missions).
As it happens, a friend of ours is an engineer for NASA. Earlier this month we got together for dinner and I asked him what was going on at NASA.

Apparently NASA (or his part of it anyway) is looking to change its focus from going to Mars to going back to the moon. He thought that this was a great idea and I very much agree.

I've yet to hear any really solid rationale for going to Mars that would lead to humans staying there or making repeat trips. In addition, spending time using the moon as a test bed for various space travel technologies and systems (including life support and food production) seems like a good way to work out the kinks in such tech over a much smaller distance and with the prospect of being able to send help in an emergency. It would also potentially allow time for better propulsion systems to be developed such that when we do eventually go to Mars, we might be able to do it in 1/2 to 1/3 the time.

Of course, NASA is rather vulnerable to the winds of politics and each new presidential administration so this might change again in a relatively short period of time. But personally I'm hopeful that the focus stays on the Moon and nearby local space for a bit.

My 2c worth,

Todd
Bear in mind that for many the ideas of living in space or going to Mars are not intended to be rational or to produce a profit. They want to go there because they want to go there. No logical counterarguments are going to change that desire. As best I can tell, that includes Elon Musk and his plans. Whether or not that'll result in long term colonization has yet to be determined.
In the long term, I imagine Mars might ultimately end up being colonized as a test of terraforming techniques as they gradually get invented. Because as useless as they are in our solar system, there's no way they won't get invented eventually. Technology that sounds cool has a way of doing that.
(03-28-2018, 08:55 PM)selden Wrote: [ -> ]Bear in mind that for many the ideas of living in space or going to Mars are not intended to be rational or to produce a profit. They want to go there because they want to go there. No logical counterarguments are going to change that desire. As best I can tell, that includes Elon Musk and his plans. Whether or not that'll result in long term colonization has yet to be determined.

Oh, I completely agree - I'm one of those people who would love to go there. But I want to see humanity go there and keep coming back and ultimately staying (not just on Mars but the Solar System - and beyond - in general).

My concern with the present focus on Mars is that it will end up like the Apollo program, which did its thing for a bit and then petered out for various reasons. IMHO a 'stepped' program of ever increasing development and capability, in which earlier steps help build the foundation for later steps, is a superior option over a massive 'leap' approach that maybe gets us that first mission to Mars a bit faster - but then doesn't do much else, at least for a long while.

As far as making a profit - getting a significant number of our eggs out of this particular basket would be good enough for me - but I suspect that kind of 'meta-goal' isn't going to be the only option and that people will figure out ways to make money off of space one way or another. Humans have a demonstrated track record of being rather good at that in most of the areas of endeavor they've taken on throughout historyBig Grin

Todd
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