Long duration Human space missions - Can we survive them?

dicktice · 2008-02-05 19:51:59

I do so hate acronyms. What the heck does m2p2 stand for?

cIclops · 2008-02-06 02:04:20

dicktice · 2008-02-06 08:30:46

Okay, according to Google: "M2P2 means MiniMagnetic Plasma Propulsion which is a system that can deliver energy from the solar wind to augument the onboard propulsion for spacecraft while minimizing the spacecraft power requirements. Potential for radiation shielding is still under investigation." The item wasn't dated.
Now, what is new is: the shielding potential has begun to be investigated by the Rutherford Lab group under Ruth Bamford, and (according to my post) results are promising. So it looks as if this (hopefully) last barrier to long-term job occupations in interplanetary space may be only temperary.

samardza · 2008-02-07 06:37:42

I just thought of this, it's only a short term baseline but has anyong compared the physiological effects between the moon missions and orbital?

cIclops · 2008-02-07 07:04:24

I just thought of this, it's only a short term baseline but has anyong compared the physiological effects between the moon missions and orbital?

There's not enough data. The Apollo astronauts only spent a total of about 25 man days on the surface, distributed between 6 missions and 12 people. That's a good reason to build the Outpost in order to compare the physiological and psychological effects with those known in LEO. Outpost missions of up to six months are planned.

Terraformer · 2008-02-07 09:06:32

But (near) instant communication is possible. The Moon is only 1.3 light seconds away, as opposed to 8 light minutes for Mars.

Would the Magnetic sheilding be permanent magnets or electro? And would itm produce a light in front of the craft like the Auroras?

dicktice · 2008-02-07 09:54:12

I should think that solar photovaic direct current would be by far the generation means of choice for energizing the "high temperature" superconducting coils.
I've read that a tenuous "arurora" would exist, but probably too faint for human eyesight to detect unaided. Suitably low light detection capability would provide a handy way to determin optimal coil positioning to accomodate differing spacecraft architectures while still in low-Earth-orbit, prior to any long duration mission.

louis · 2008-03-27 07:44:01

Bone loss is more or less manageable with exercise I would say judging form ISS experience. Artificial gravity would be a wasteful and potentially dangerous addition to the craft. Forget it.

Radiation exposure is not a problem . We can have hidey holes on board for major radiation events.

The immune system is of some concern. On the plus side of course, they are going somewhere where the likelihood of catching a bug is probably small (though we don't know for sure). But this is something we need to look into more.

Having said, none of the long stay astronauts has keeled over and died.

Are we sure the immune system isn't working less efficiently because it isn't being challenged in the it would on earth on a daily basis? Do people isolated in the Antarctica experience similar immunity reduction one wonders?

Michael Bloxham · 2008-03-28 02:46:24

Artificial gravity would be a wasteful and potentially dangerous addition to the craft.

Why?

cIclops · 2008-03-28 03:02:00

The system would add mass, it would also add complexity and therefore risk.

louis · 2008-03-28 07:47:20

Yes, Ciclops has got my thinking right on that- added mass is wasteful and complexity always brings risk as we have seen with various aerospace disasters.

On the radiation issue, water is said to be a good radiation barrier. But is irradiated water itself safe to drink? Just wondering, as I was thinking one could build a safe place at the centre of the craft and surround it with the water tanks - or to look at it another way, the safe place would be in the centre of a water tank.

idiom · 2008-03-28 19:31:36

A minimal amount of 'gravity' simplifies a lot of systems, reducing overall complexity. The same way a tap on the thrusters can settle main engine tanks instead of using positive expulsion mechanisms.

cIclops · 2008-03-29 01:50:43

All the systems will have to function in zero gravity at the beginning and end of the journey, and probably during course corrections. Perhaps some pumps can be eliminated, however it's unlikely such savings will offset the extra mass of the rotation mechanism and all the other components that also have to work during rotation.

louis · 2008-03-29 05:35:12

Unless you were the optimistic type, you'd also have to plan for failure of the rotation mechanism, in which case you would have to have all the pumps ready for zero G conditions. So there would be no mass or complexity saving.

cIclops · 2008-03-29 05:52:26

Indeed, all sane engineers would have to plan for that

If the rotation mechanism did fail early in the mission, the most important consequence would be for the crew. The surface mission would probably have to be canceled unless there was a backup way to deal with the effects of zero gravity. If there is an alternate way to deal with zero gravity, why not use it instead?

idiom · 2008-03-29 18:44:07

While the rotation is operating you are not relying on your pumps and whatnot. Everything is passively pressurised and so on. If you don't have that then you rely on active system the whole way there and back.

Commodore · 2008-03-30 22:08:06

While rotation surely adds a certain amount of mechanical complexity, its also the only way to get people in a useful quantity to Mars, or the surface of any other body on the other side of interplanetary space in any condition to do anything productive.

We can go one of two ways initially. One is to do a really small ship and crew living off MREs with a big, powerful, probably nuclear rocket, resulting in a transit of a couple months max and putting much more surface equipment on a separate ship with much assembly required. Or preferably, in my opinion, we can build a much larger craft, incorporating the full range of techniques to produce as Earth-like environment as possible, capable functioning indefinably in interplanetary space conditions with a large crew. The latter, while more expensive at first, it can be parked in Mars orbit, allowing the far cheaper shuttles to do follow up flights, because crews have some place to rehabilitate.

louis · 2008-03-31 05:58:43

Commodore -

Where's your evidence for these statements.

We know that people on the ISS have stayed for a year in zero G and been perfectly productive. We know also that the body does recover when returned to 1G. There is no requirement for the crew when they land to do anything much in particular of a strenuous nature. They can simply take a while, a few days if necessary, for their bodies to become re-accustomed to gravity. In any case once there is a human settlement established on Mars, the landing crew won't have anything to do. The people already on Mars can cater for their immediate needs in the gravity recovery phase.

I think the effects of return to gravity are often overstated. We have seen pics of people being lifted out of space craft. But this is not a reflection of physical collapse. It is to do with lack of use of the leg muscles. The ability to stand and walk soon returns.

Commodore · 2008-03-31 07:29:39

I think once on the Martian surface, its going to take a lot longer than a few days for bone and muscle mass to recover, and even after that there going to have to be careful.

cIclops · 2008-03-31 12:02:18

The big unknown is will Mars gravity be sufficient to restore the astronauts to full health after their six month outward transit. If the recovery process is too slow, they will be extremely weak for their 18 month stay and unable to explore. Even worse, the return journey may kill them.

After leaving LEO, all astronauts have many people to help them and full medical facilities on Earth, on Mars they will have to manage by themselves with their basic medical equipment. It's absolutely vital that we know before they leave that they can survive the whole voyage.

naitsabes · 2008-03-31 12:47:54

Space Radiation Too Deadly For Mars Mission

http://www.space.com/missionlaunches/08 … lding.html

louis · 2008-03-31 14:48:18

Well I was never suggesting they roam around the surface of Mars in their underpants!

Also, I think that my suggestion that the habitats should be inflatables inside trenches covered in a large mound of regolith will offer complete protection to the colonists while they are in the habitat.

If necessary work on the surface could be limited to night-time, though presumably that will have no effect on reducing cosmic rays.

I am a little unclear how the threat balances between cosmic rays and solar radiation. Anybody have an idea about that?

Certainly we know that no one who's been on the ISS a long time has died or as far as I know suffered serious ill health. Is the magnetic field of earth that effective against cosmic rays?

SpaceNut · 2008-03-31 17:30:49

Thanks for the article link naitsabes, but an article that gives no facts or figures is usually hype....So went searching for what are considered safe levels as well as what has been measured.

First the measured Data from Odyssey's Martian radiation environment

Of course radiation comes in different wave lengths and energy levels.
Cosmic Radiation, Terrestrial Radiation and lots of other sources we are exposed to eveeryday.

What radiation levels are considered safe?

Radiation, how much is considered safe for humans?

redhorizons · 2008-04-01 12:55:15

This is a little off the subject, but seemed relavent for how we would GET to Mars.
Suspended animation?

Zapol expects that combining hydrogen sulfide inhalation with chilling the body, another method of slowing down the body's machinery, could cut metabolism by up to 90 percent.

"Nine months in a spaceship heading out to Mars takes a lot of oxygen to burn, food and water to consume, and produces a lot of waste [carbon dioxide]," said Zapol, who is on the Institute of Medicine's Committee on Aerospace Medicine and the Medicine of Extreme Environments.
Theoretically, cutting metabolism would reduce the need for consumables and produce less waste, enabling spacecraft to travel lighter and faster.
"Wouldn't it be nice to arrest metabolism safely for long periods of time and reverse it when you wanted to?" Zapol said.

http://www.livescience.com//health/0803 … ation.html

Opinions/Comments???

JoshNH4H · 2008-04-01 13:46:08

isn't it lethal to breathe H2S for long perods?

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