# New ISS machine makes water from waste CO2

Thirsty astronauts orbiting the Earth aboard the International Space Station (ISS) have just gained a handy new source of water to eke out supplies shipped up from Earth and those from the station's famously erratic urine recycling system. The new Sabatier Reactor, named for the Nobel prize-winning French chemist who developed …

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#### Pricey water

By my calculations, assuming it works as expected, it'll cost NASA \$16,250 per litre of water. My God, that's even more expensive than petrol in the UK at the moment!

#### Macro Economics... Supply vs Demand...

You have to remember how much it costs to ship a litre of any liquid to the space station.

So the real question is how much money is saved by recycling this water.

#### @Tim Spence

Same price as a kilogram of *anything* else sent up in the shuttle.

this is why lower the cost of 1Kg to LEO is *the* space design problem.

#### A tonne of water a year?

Three litres a day for six people isn't going to go very far, I think.

Better perhaps to ship up some nice empty bottles; given the price some people will pay for bottled water, it'll probably make a nice profit.

#### Re: A tonne of water a year?

The output from the Sabatier Reactor is in addition to existing water reclamation systems, particularly the "Urine Processor Assembly" as noted in the article. It's about stretching the existing resources as far as possible to reduce the amount of replacement materials that need to be shipped up.

#### Wow

OK, it's half way through 2010 (nearly) so "by 2014" means 3.5 years of output.

1 tonne per year = 3.5 tonnes of water.

That's 3,500L water, at \$65 million....

So that'll be \$18,571 per Litre!

Bloody hell, that's even more expensive than London!

#### Refine the process further

If you just burn the methane you get CO2 and more water?

So, no waste at all?

#### Pointless...

Since you'd use up oxygen to burn the methane...

#### service industry

> NASA will not buy hardware, but instead will purchase the water service. If the system does not work, NASA will not pay for it.

>

> If the reactor works, Hamilton Sundstrand could receive up to \$65m by 2014.

Hmm, and if it doesn't work who pays the technician's call-out fee?

"Sorry sir, we don't do free estimates. That'll be \$20m for the visit, but don't worry. If it needs

#### So..

It's a vending machine then?

#### Cost per litre of water to LEO

A space shuttle launch costs \$450 million*, and puts 24,400 kg** of payload into LEO. A litre of water is 1kg. So taking water up on the space shuttle costs \$37,500 per litre.

In comparison, under \$20,000 per litre seems a bargain.

**http://www.astronautix.com/lvs/shuttle.htm

#### All costs aren't equal

I bet the unmanned Russian supply ships in use now cost a whole lot less than \$450M per launch. Be interesting to see the cost/litre the Russian way.

#### Or even the European ATV...

But I'm too lazy to google up the figures for it.

#### Re: Or even the European ATV.

Ah yes. But with European rocketry, your litre of water has a nasty habit of being suddenly and unexpectedly converted into a puff of steam somewhere between French Guiana and the ISS.

#### Cooling!?

"...and cooling some electronic equipment."

This seems, um, poorly considered! Is the ISS not actually up in space right now then?

I know they use IBM (Lenovo?) laptops as seen in some of those tour vids, but surely something can be done by putting computing power outside the life supported areas. Might even be able to manage some serious overclocking on those CPUs as a result!

#### @Stu

"but surely something can be done by putting computing power outside the life supported areas."

Think of it this way. Space is a very near vacuum. The *entire* structure is inside a vacuum flask.

If you want to dump heat you can do it by conduction, convection or radiation.

Conduction. Nowhere to go.

Convection. No fluid *outside* the structure to convect.

Leaving radiation. Hence the rather large flat structures that aim to dump waste heat into the shadow of the station.

Mine would be the college physics textbook in the pocket.

#### cooling...

Just because space is cold, doesn't mean cooling things is easy. Vaccum is a very good insulator. That's why they put it in thermos flasks.

#### Surprisingly hard to cool in space

It's a lot harder than you think to cool off in space. Whilst the vacuum of space is damn cold, it's also lacking one thing that makes cooling efficient: air. On earth, it's possible to efficiently cool your computer using a combination of radiation and air convection. In space you only have radiation, which isn't particularly efficient. The use of radiators in shady spots mitigates the situation, but placing the computer equipment "outside" wouldn't really help matters much and would have the additional problem of requiring the equipment to be rated for use in a vacuum.

> ... but surely something can be done by putting computing power outside the life supported areas.

One must keep in mind that up there in Low Earth Orbit, there is almost no atmosphere (i.e., zero, for practical purposes) outside of the spacecraft to allow for the efficient transfer of equipment-generated heat into a surrounding medium, which would then be carried away by kinetic and/or convective processes.

The only real way to get rid of the heat is by dissipating the energy into the surrounding near-vacuum "photonically" through a phenomenon known as "black body radiation:"

Since direct thermal radiation into a surrounding "empty" void is a very inefficient process (compared to the kinetic/convective transfer of heat between two materials in close contact, like a PC's CPU heat sink with the surrounding atmosphere), heat generated by the station's equipment would build up very quickly if there wasn't a way to get rid if it in a timely manner.

The station maintains its temperature balance by using closed-loop water systems to carry excess heat to giant external radiating panels, which dissipates the heat as thermal (infrared) radiation.

Another way to use this excess heat would be to pass it across a thermocouple, so the excess heat could be converted into electricity for use in charging batteries and running low-power experiments. I wouldn't be at all surprised of the station already makes use of some of its excess heat for this purpose.

#### Re: Cooling!?

It is a common misconception that because space is "cold" that cooling is not a problem. The real problem is that space is largely a vacuum, so there's little gas (nitrogen and oxygen here on Earth) to effect a kinetic transfer of energy-- like how the temperature seems cooler on Earth when the wind is blowing, which we refer to as "windchill."

In space, the primary means of cooling is to radiate the heat energy away as infrared light. To get heat from inside the ISS to the radiators located outside the ISS, they use a circulating system of water (and ammonia) as the heat transfer medium.

Really, NASA explains it far better than I could:

http://science.nasa.gov/science-news/science-at-nasa/2001/ast21mar_1/

#### @Stu

How's that going to help? Where's the heat going to go?

How does heat travel? Convection, conduction and radiation. Radiation is slow, conduction is the problem and there isn't any air.

#### Centrifugal Urine Processor Assembly?

CUPA?

What is in the astronaut's food that causes them to excrete graphite? It must be painful, excreting graphite.

#### Diamond squeezer

Other forms of pure carbon would be worse.

#### Space Pencils

The Sabatier reactor's carbon bi-product (as graphite) would make for a perfect replenish-able source of pencils.....

If only they had a way to handle to graphite dust given off.....

#### Zero-G Nanodiamond

Since the graphite would be so pure, it would probably be perfect for conversion into zero-g nanodiamond matrices that could be used for things like constructing ultra-strong, ultra-clear window glass and other "supermaterials."

Vernor Vinge, Charles Stross, William Gibson, and other authors have all mentioned "diamond glass" as being a common material used for window panes in spacecraft and orbiting habitats...

#### Contract-crazy

So NASA is shipping stuff to the ISS that they aren't even sure will work? Well that seems sensible....

#### Only pay for what it produces.

This is a *quantum* leap in NASA's contract negotiating skills. Payment by results. Who'd have thought NASA would *ever* do such a thing. The times are a-changing.

As for NASA shipping stuff that they aren't sure would work what of the liquid handling urine recycling thing that has given much innocent amusement on these pages.

#### Mars anyone?

Cool. Full recycling will probably be necessary if a long duration voyage is envisaged. Next thing they will have to do is try to grow their own food.

I thought that this was the original reason for the ISS as a stepping stone to the outer planets Mars etc.Luckily Pres.Obama has said that it will still be up after 2020,and the return capsule for the Constellation Rocket is to be used as a life boat for the ISS.

It's rather difficult to be entirely confident whether a machine will work properly in low-Earth orbit without, well, sending it to low-Earth orbit.

#### And for Mars?

Sending this to the space station may have a secondary agenda for the future exploration of Mars.

Interestingly this has been suggested as a means of producing rocket fuel and other resources on Mars (ref: "The Case for Mars", Robert Zubrin). The plan calls for an Earth return vehicle being sent to Mars ahead of the crewed landers by about two years. The return vehicle would carry with it a few tonnes of Liquid Hydrogen which is reacted with CO2 from the Martian atmosphere after landing to produce Methane and water (which is split back to H2 and O2, H2 being fed into the reaction again and the O2 stored). This way the lander manufactures the propellants for the return trip before the the astronauts are sent to Mars. With no need to take the return propellants with them them the crewed vehicle is much less massive and can built and launched much more easily than a completely self contained mission.

Note also that this technique also can provide the basic living requirements of O2 and water for the astronauts on Mars.

This can also be further extended if a ready supply of water ice can be found close to the landing site, thus allowing more H2 to be produced.

Zubrin has called this "living off the land" with respect to Mars and sees it as a "game changing" concept for human exploration of Mars and eventual colonization. It has been seriously suggested that this technique be trialed by using it to fuel a unmanned Martian sample return mission.

Anyone interested in finding more search for "Mars Direct" in a good search engine near you.