Manned Mars Mission

[TheGamingNoobster]

Please tell me all of the faults with this. Please do.

This is for a manned mission to Mars. We understand that an effective chemical rocketry fuel is LOX and LH2, and an effective radiation shield is water (it halves radiation for every 7 cm. What would the flaws be in creating a water tank around the crew cabin in which they can drink from and stuff and will shield the crew from radiation and splitting the fuel prior to the MOIB (Martian Orbital Insertion Burn). Once landed, crews can use martian soil to cover up bases etc. from radiation.

Some stuff to build up from: pumping the water to the water splitters, storing the LOX and LH2 once it becomes a chilled, condensed liquid (tools required and extra storage space) and reliability.

I put this up because I have thought about it for a while and I have searched for similar results to no avail. I have heard some weird ideas for manned mars missions but this was one that, as aforementioned, I have never heard of.

Does anyone have any alternate ideas?

Edited May 26, 2015 by TheGamingNoobster

[Reddragon]

"...which they can drink from and stuff and will shield the crew from radiation..."

Yeah, this doesn't sound right at all.

[magnemoe]

Splitting water uses a lot of energy so you would need giant solar panels or an reactor.

Then you have that you can just as well use vasmir.

You still need the water on the return trip, however the idea to split water might make sense for other parts, especially the burn to getting back to earth orbit.

[TheGamingNoobster]

Thanks all for the responses. In response to Reddragon's post, I have heard (but have never verified it) that it isn't healthy for people to drink pure water. That may be another fault.

[SargeRho]

Yeah, pure H2O drains your body of salts and minerals, which you kind of need to function, so it's not a good idea to drink pure water. However, using the water tanks to aid in radiation shielding isn't a bad idea at all.

[Reddragon]

Also, the crew would basically drink up their own radiation shielding...

Edited May 26, 2015 by Reddragon

[TheGamingNoobster]

Also, the crew would basically drink up their own radiation shielding...

You can recycle the water through the system.

Onto SargeRho's point, extra weight would be required to bring replacement salts and stuff. That or some water would have to be out aside.

I am arguing for and against the idea BTW.

[Nibb31]

It's not a new idea. Having the water tanks surrounding the habitation module is a pretty common idea. Typically, the water is scrubbed and recycled, like on the ISS.

However, you wouldn't want to use water for propulsion. First because it would require a lot of power to break down the water into LOX and H2. Second because expending the water would deplete your radiation shield, which is a bit counter-productive.

Interestingly, what you propose is exactly the opposite of the fuel cell system that was used on the Space Shuttle. It converted LOX and H2 from the propellant tanks into power and drinking water for the crew.

[TheGamingNoobster]

It's not a new idea. Having the water tanks surrounding the habitation module is a pretty common idea. Typically, the water is scrubbed and recycled, like on the ISS.

However, you wouldn't want to use water for propulsion. First because it would require a lot of power to break down the water into LOX and H2. Second because expending the water would deplete your radiation shield, which is a bit counter-productive.

Interestingly, what you propose is exactly the opposite of the fuel cell system that was used on the Space Shuttle. It converted LOX and H2 from the propellant tanks into power and drinking water for the crew.

Well, my thinking is the opposite to rocket scientists of the 70's! I am seeing that the power required to convert water to LOX and H2 is quite high. Does anyone have any numbers (Not that I am doubting you guys!)

[heng]

ask those guys: MarsPolar Project

they are going after the water ice on duna's... errr: mars' poles, so they obviously have some wet dreams :-D

[Findthepin1]

it's way too much water aboard the ship. water is heavy. they don't need all of it, they can use a thin layer of titanium or something instead. like they still need water but not nearly as much.

[fredinno]

Well, my thinking is the opposite to rocket scientists of the 70's! I am seeing that the power required to convert water to LOX and H2 is quite high. Does anyone have any numbers (Not that I am doubting you guys!)

2.6 KW/h per cubic meter of water. You could probably do this with high-efficiency solar panels (especially since they are becoming better all the time). Honestly though, your idea of splitting water is really not that great if this means taking away from your radiation shield (would increase radiation exposure over time to unhealthy levels). The only advantage I can see with the splitting- water idea is that the hydrogen will be much less likely to boil off.

On the bright side though, it does consume less electricity than my Mars mission idea of using high-power ion drives for propulsion!

it's way too much water aboard the ship. water is heavy. they don't need all of it, they can use a thin layer of titanium or something instead. like they still need water but not nearly as much.

Water one of the best materials for radiation shielding- Titanium is a lot worse for this purpose (things with lots of hydrogen shield particle radiation the best.

And yes, water is heavy, so the radiation shielding should only mainly be on the interplanetary transit habitation module.

[SargeRho]

Also using light metals as radiation shielding is generally a bad idea, due to secondary radiation.