New Mars Forums

We have been doing the needed design and use of water recycling for some time onboard the ISS. All of which was in the ISS threads but lost in the crash...

The history of water for the ISS was from start of manned presence until 2008 or so was one of recycling 40,000 pounds per year of water from Earth to resupply a minimum of four crewmembers for the life of the station. On the space station, people will wash their hands with less than one-tenth the water that people typically use on Earth. Instead of consuming 50 liters to take a shower, which is typical on Earth, denizens of the ISS will use less than 4 liters to bathe. With the water being reclaimed for the Russian oxygen generator system.

In 1998, NASA announced it had built a human waste reclamation bioreactor designed for use in the International Space Station and a manned Mars mission. Human urine and feces are input into one end of the reactor and pure oxygen, pure water, and compost (humanure) are output from the other end. The soil could be used for growing vegetables, and the bioreactor also produces electricity.

http://www.colorado.edu/engineering/ASE … waller.pdf
http://en.wikipedia.org/wiki/Bioreactor

http://www.sciencedaily.com/releases/20 … 210838.htm
http://space.about.com/od/livinginspace … ycling.htm

Aboard the International Space Station, astronauts have been able to drink recycled urine due to the introduction of the ECLSS system. The system cost $250 million and has been working since May 2009. The system recycles wastewater and urine back into potable water used for drinking, food preparation, and oxygen generation.

http://www.space.com/missionlaunches/09 … urine.html

But with all that is said and done any system will need backups both mechanical or biological.....

Ok, I'll comment. Mars Odyssey measured radiation in Mars orbit. It was supposed to be complemented by a radiation sensor on the Mars 2001 lander, this would provide "ground truth". NASA and the nuclear bomb guys in the military have really accurate formulae to calculate radiation absorption, so they can calculate a very accurate estimate of how much radiation gets through Mars atmosphere to the surface. But the lander was supposed to provide "ground truth" to validate those calculations. But the lander used the same chassis as Mars Polar Lander, so they held off launching until after the problem with Polar Lander was identified. Unfortunately then they got bored and forgot about the 2001 Lander. Then some scientists noticed this lander, complete and ready for launch sitting in storage. They converted it into Mars Phoenix, removing several instruments to make room for their new instruments. The radiation sensor was one instrument removed. The In-Situ Propellant Production Precursor was another. Phoenix was nice and all, but the removed instruments were a great loss. But now we have the RAD sensor on Curiosity, so it'll provide the needed data.

The MARIE instrument on Odyssey found radiation in Mars orbit is about twice that of ISS. You see, Mars doesn't have a magnetosphere and anything in Low Earth Orbit (such as ISS) is within and protected by Earth's magentosphere. But calculations show radiation on Mars surface is half that of ISS, which means about 3/4 is blocked by the atmosphere. More important is the "spectrum", or which types of radiation get blocked.

Heavy ion radiation is the nastiest. Light radiation shielding can actually make it worse. Heavy ions are large atoms such as iron. Cosmic radiation (also known as Galactic Cosmic Radiation) gets pulled in by the Sun's gravity, and more dramatically by the Sun's magnetic field. By the time it reaches the inner solar system, cosmic radiation has been accelerated to close to the speed of light. When a heavy ion GCR particle hits shielding, it can split into multiple particles. Each is smaller in mass and slower, but still larger than alpha particles and moving damn fast. So this means light shielding can convert heavy ion radiation from a high calibre bullet to a shotgun blast. When it hits your body, each particle blasts through a path of cells. So splitting heavy ions actually causes MORE of your cells to get affected. The best shielding against heavy ions is liquid hydrogen, because the hydrogen is so light it doesn't split the ions. Impact with hydrogen doesn't slow the ion much, but each impact slows it a bit more and a bit more until it's slow enough not to be dangerous. That takes a fairly thick tank of liquid hydrogen. The second best shielding is water, H2O. Third best is plastic high in hydrogen and composed of just hydrogen and carbon, such as polyethylene or polypropylene. Nylon or polycarbonate contain a small quantity of medium weight atoms, such as chlorine. These heavier atoms can split heavy ions; not good.

The good news is the best shield against heavy ions is the atmosphere of Mars itself. It's low density but miles thick. If you look at the report by the MARIE team, the atmosphere of Mars will block 90% of heavy ion radiation at a high altitude plateau such as Meridiani Planum. At a low altitude location 2km below the datum, such as Mawrth Vallis, the atmosphere blocks 99% of heavy ion radiation. So the safest place in our solar system, next to Earth, is the surface of Mars.

Other forms of radiation: beta is blocked by a single sheet of paper or plastic film. In fact it's blocked by the epidermis of human skin. A spacesuit or spacecraft will block it easily. Alpha is blocked by a single sheet of aluminum foil, so again a spacesuit or spacecraft will block easily. Neutron radiation does not survive long enough to make it from the Sun to the orbit of Mercury, much less Earth or Mars. UV light can be nasty, Earth's ozone layer blocks 100% of UV-C and the vast majority of UV-B. Light we get on the surface is UV-A, the low energy stuff. UV-B causes skin cancer, and UV-C will sterilize or kill your outer layer of skin. Even mild exposure to UV-C can cause cataracts later in life. So NASA developed a spectrally selective coating for windows or spacesuit helmet visors. It consists of very thin layers of gold, nickel, and silver-oxide. It lets 80% of visible light through, but blocks 99% of UV. It also reflects about 40% of IR, and can be adjusted. With the metal layers applied one way it reflects more short wave IR and less long wave. Long wave IR is radiant heat from warm objects like the floor, walls, furniture, etc. Short wave IR comes from very hot objects like the Sun. So reflecting more short wave and less long wave traps heat in. The other way it helps keep heat out. This was developed by NASA, but sold to commercial industry. They sell windows with this under two brand names: Low-e or Heat Mirror. In Canada it's oriented to trap heat in, when sold to southern states it's oriented to keep heat out. All this helps control heat in a spacecraft, as well as protect against radiation. Since it's metal, it also blocks X-rays.

So what gets through? Proton, light ions, and medium ions are somewhat blocked by Mars atmosphere but not as effectively as heavy ions. Gamma rays also get through. The best shielding against these forms of radiation is soil, or sand bags. When Robert Zubrin wrote the Mars Direct plan he called for bringing empty sand bags. Astronauts would fill them with Mars soil, and pile on the habitat roof. That's actually the best. For a permanent settlement, you want 2 metre depth of soil on the roof.

To limit radiation exposure to the same dose per year as a nuclear reactor worker, a permanent base needs 2 things: 2 metre of soil on the roof, and limit time outside in a spacesuit to 40 hours per week. That's a work week, not a problem. A greenhouse would have a glass roof (or plastic film) coated in that same spectrally selective coating. So time in a greenhouse would be the same as time outside in a spacesuit.

For a science mission, radiation on the surface is overall half that of ISS. And sand bags will reduce it further. And the nastiest form of radiation is the one blocked by Mars atmosphere. So again, not a problem.

Oh, one of the linked articles said a mission to Mars would be 6 months there, 6 months back, and 18 months on the surface. But the planets orbits align for a return after just 14 months. Mars orbit is elliptical, if you go the wrong year it could be a bit more, up to a maximum of 16 months, but not 18.

yes it's a bit disheartening... Maybe the time of bb's is passing, everyone on social media...

Wow, look at those dunes!

http://i.imgur.com/8QOhL.jpg

From http://mars.jpl.nasa.gov/msl/multimedia/raw/

edit: someone over at UMSF made this, omfg: http://www.nivnac.co.uk/mer/index.php/msl0002

Incredible!

Wow, look at those dunes!

http://i.imgur.com/8QOhL.jpg

From http://mars.jpl.nasa.gov/msl/multimedia/raw/

edit: someone over at UMSF made this, omfg: http://www.nivnac.co.uk/mer/index.php/msl0002

Incredible!

Video of MSL descent (thumbnails for now): http://youtu.be/UcGMDXy-Y1I

Congrats to NASA and JPL.

   Bob Clark

I think it's very stupid plan "one way ticket" I mean if they're already there why not bring them back? I say this mostly because yeah it's durable when you're younger but what when you're over 60 or 70 or even 80 years old and living on Mars?! It's certain that old people would be a huge drag for other people living there.