# How would I transport an atmosphere?

An abandoned outpost from a long extinct race is discovered. It can easily be repaired and would make an ideal location for a colony, however it has been breached and any usable air has been long lost to space. The outpost has its own power systems that we are capable of turning back on and using, however there is no method on the station to create a breathable environment for humans. It's quite the journey and a colony ship would need to be in transit for more than a decade to reach its destination.

If a colony ship was dispatched to this location, what would it need to bring to generate enough Earth-like air for the population to breathe and use?

My first idea was solid ammonia and liquid oxygen… Burn the ammonia and let it release its nitrogen along with water. Use electrolysis to recover some of the oxygen back as required (or leave it as usable water). The issues here:

• Way too high of a oxygen to nitrogen ratio… as nice as ammonia is for this, the nitrogen content is relatively low and is created at a 3:1 ratio with oxygen.
• Need to carry too much liquid oxygen. It would be nice if one chemical compound can be released instead of two separate ones… also not a fan of storing high pressure gas on a long trek colony ship
• Too much hydrogen… there are a few uses for it (water/fuel), however the ratio of nitrogen to hydrogen is too low and an excess of hydrogen is created in trying to get Earth-like conditions.

Assume any chemical compound can be reasonably manufactured. Liquid gasses require high pressure and have some degree of danger in space transport… solid compounds preferred, but not an end all.

What would you take on your colony ship to create an Earth-like atmosphere in as little amount as storage space possible and as safely as possible?

It is preferable to bring the material on the ship as opposed to trying to harvest it. The tech level on the propulsion systems is limited and the speed to get there depends on some gravitational slingshotting to get it up to speed already, so there isn't the opportunity to stop to harvest anything and then re accelerate.

• @Nick2253 See this question – DoubleDouble Feb 18 '15 at 22:14
• I figured CO2 could be generated by burning a small amount of the plant matter thats part of the farming operation on the colony ship. Or bring a small dead tree to burn upon arrival. – Twelfth Feb 18 '15 at 22:15
• @DoubleDouble A pure oxygen environment is regularly used on Earth for medical purposes. And without something to oxidize, a pure oxygen atmosphere won't be flammable. – Nick2253 Feb 18 '15 at 22:17
• What's wrong with frozen air? – Oldcat Feb 18 '15 at 22:33
• No one did put Spaceballs referrence here? Am I really the first one to do it? Ok, here you go: youtube.com/watch?v=VptOUWC-Itc – Pavel Janicek Feb 19 '15 at 10:02

## 6 Answers

Per your question, it sounds like you preferred something that was not a pure oxygen atmosphere. In that case, nitrous oxide ($N_2O$) might be an a good match. At 1 atmos. pressure it becomes liquid at -88.5 °C solid at -90.9 °C easily maintained at a 10 year trip in space.

On arrival, $N_2O$ could be easily decomposed into $O_2$ and $N_2$.

I am not aware of any stable compound that has a ratio closer to the N/O ratio of earth's air. The atmos. pressure in your station would only be 60% of "normal" but that might be acceptable.

Ammonium nitrate melts at 169 C, and leaves no residue when heated:

$$\text{NH}_4\text{NO}_3 → \text{N}_2\text{O} + 2\text{H}_2\text{O}$$

Like Gary says $\text{N}_2\text{O}$ can be decomposed into nitrogen and oxygen.

But for the reality check, hydrogen, nitrogen and oxygen are very common elements. The colony ship is bound to find some compounds they could extract it from, although it takes longer.

• Good pt. re: availability. You would also be very likely to want water and food. CHON -- it's what we are made of. I have to assume this question is intended as a startup supply to tide you over before you start mining comets and asteroids. – Gary Walker Feb 19 '15 at 19:17
• +1, I gave the check to Gary's answer, but your expnansion here is very useful. Thankyou. – Twelfth Feb 20 '15 at 17:57
• I definitely like the advantages that this has over N2O, not only that it's a solid at room temperature (much easier to load into your space ship) but that it also decomposes into N2O and water. – Draco18s Jun 21 '18 at 1:29

People in an enclosed environment don't need anything but oxygen. While it's toxic at high partial pressures, you can account for this by having a lower ambient air pressure than what exists on Earth. For example, an atmosphere with a pressure of .2 bar will have enough oxygen for people to breathe, but won't be toxic. Issues with flammability are also tackled by reducing partial pressure, since it is what determines reaction rates in a gas. Reducing partial pressure will also reduce the structural loads on your habitat, making it easier to patch holes and reducing the rate of air loss if there are any small breaches.

If you don't like liquid oxygen, there's another convenient way to transport it: liquid ozone. Ozone has a higher boiling point than oxygen by about 20 degrees, and is also 50% denser than oxygen. It also self-oxidizes, so you can burn it to produce energy, with the byproduct being oxygen.

The downside is that anything that's a strong enough oxidizer that you can burn it to produce another strong oxidizer is a really good oxidizer which means that a tank of liquid ozone laying around needs to be treated really carefully, or it will explode, even without anything else to burn, because ozone will burn itself. But hey, lower volume for storage and free energy if you treat it right.

• Assuming there is some co2 added to the mix, would plant life be able to handle this? And it still seems like a relatively high risk of combustibility, even at the lower pressures...am I wrong there? – Twelfth Feb 18 '15 at 23:14
• Combustibility is mostly a matter of partial pressure rather than fractional concentration. – Mark Feb 19 '15 at 0:21
• I like the answer, but I'm going with the check mark beside the answer that came close to an earth environment. – Twelfth Feb 20 '15 at 17:57
• WRT flammability in a pure oxygen atmosphere, remember Apollo 1. – jamesqf Nov 9 '16 at 17:02
• Ozone is unstable. It will try to revert back to dioxygen, and will produce lots of energy doing so. Hot ozone is more unstable, but even liquid or solid ozone won't last 10 years. Also if it starts to heat up, it will explode. And the very hot, high-pressure newly created oxygen will be happy violently oxidizing everything it touches, be it by corroding it or setting it on fire. – Eth Jun 18 '18 at 15:01

There are several sustances that can use to generate your atmosphere.
Sice they are quite large, right now I'll post only one of them and when I have more time I'll post the other ones.

You will note that this answer is quite large. That is because I also explain how to produce the sustance, and how to produce the sustances which produce it (maybe that information could be useful for someone who is willing to manufacturate the compound instead of bring it from Earth). If you aren't looking for that, only read up to production title (without include it), In order words, only read the first quarter/fifth of the post.

Also note, that the most important part of my answer is under the tile usage.

Finally, if someone have any question, ask in comment. I'll do my best to address the problem.
Good luck reading!

# Nitrous Oxide $\text{N}_2\text{O}$ (Or ammonium nitrate $\text{NH}_4\text{NO}_3$)

$\begin{array}{|c|c} \hline \text{Molar Mass} & 44.013 \text{g/mol} & \\ \text{Density} & 1.977 \text{g/L (gas)} \\ \text{Melting Point} & −90.86 \text{°C} \\ \text{Boiling point} & −88.48 \text{°C} \\ \text{Price} & \text{¿?} \\ \hline \end{array}$

Or ammonium nitrate, see on industrial production.

Introduction: Commonly know as laughing gas or nitrous. At room temperature, it is a colorless non-flammable gas, with a slight metallic scent and taste, and faint, sweet odour. At elevated temperatures, nitrous oxide is a powerful oxidizer similar to molecular oxygen.

Uses: Futhermore build an atmosphere, you can use nitrous oxide in several ways.

• Recreational (due to euphoric effects upon inhaling).
• Anaesthetic and pain reducing on surgery and dentistry. (At 50% concentration can be administred by non-professional people)
• Rocket propellants (used as an oxidizer). Can be use also as a monopropellant rocket with a catalyst.
• Motor racing to increase the power output of engines.

Advantages:

• It's non-toxic. (Long-exposure and abuse can produce vitamin B12 defficiency...)
• It's stable at room temperature -making easy to store and carry on flight-.
• It's possible to decomposed readily to from breathing air.
• It has high density and low storage pressure (when maintained at low tempertarue). That enable it to be highly competitive with stored high-pressure gas systems.

## Storage:

This can be storaged in 20-25 bars tanks at -20 °C or in high pressure tanks at 45-60 bars.

## Usage:

In the presence of a heated catalyst, $\text{N}_2\text{O}$ will decompose exothermically into $\text{N}_2$ and $\text{O}_2$, at a temperature of approximately 577 °C (this even produce energy!).

$$2\text{N}_2\text{O} \Rightarrow 2\text{N}_2 + \text{O}_2 + 82 \text{ kJ/mol}$$ $\begin{array}{|c|c|c|c|c} \hline \text{Examples} & \text{N}_2\text{O} & \text{N}_2 & \text{O}_2 & \text{Energy}\\ \hline \text{by Mass} & 1,000\text{g} & 636.48\text{g} \text{ }(63.64\text{%}) & 363.51\text{g} \text{ }(36.35\text{%}) & 1,863.08\text{ kJ}\\ \text{by Volume} & 1,000\text{cm}^3 & 1,006.33\text{cm} \text{ }(100.63\text{%}) & 502.92\text{cm}^3 \text{ }(50.29\text{%}) & 3,683.32\text{ kJ}\\ \hline \end{array}$

With nitrous oxide you can build and atmosphere of:

$\begin{array}{|cc|r|cc|r|} \hline \text{Chemical} & \text{gr/mol} & \text{Percentage} & \text{Mol Fractal} & \text{Mol} & \text{Partial Pressure} \\ \hline \text{N}_2 & 28.0134 & 63.65\text{%} & 2.272 & 0.666 & 67.550 \text{ kPa} \\ \text{O}_2 & 31.9988 & 36.35\text{%} & 1.135 & 0.333 & 33.775 \text{ kPa} \\ \hline \text{Total} & 60.0122 & 100.00\text{%} & 3.408 & 1.000 & 101.325* \text{ kPa} \\ \hline \end{array}$
101.325 kPa = 1 atm

Okey... that is... fine.

• A bit high oxygen value: Humans need around 21 kPa of oxygen to "work" properly, you will have 33.775 kPa, your people wouldn't suffer hyperoxia. Hyperoxia is produced when oxygen is above 50 kPa it becomes toxic. You will survive, but I think (complete and subjetive personal opinion) your crew will need a few days to adapt their lungs after stop coughing. Also, (again, my opinion) they will suffer some slightly diseases or deficiencies after some years.
• You can improve that reducing the overall pressure from $101.325\text{ kPa} \rightarrow 63\text{ kPa}$. So you will have $42\text{ kPa N}_2$ and $21\text{ kPa O}_2$. Good!
Also, reduce the overall pressure has an advantage: if there is a damage in the ship/station's hull, air will scape slowler from it, giving more time from crew to fix it.

Also, because of the large heat release, the catalytic action rapidly becomes secondary, as thermal autodecomposition becomes dominant (that means you don't need to store much catalyst).
Its catalyst can be any of this (I think): (Note that I don't know about catalysts and their usages)

• Rhodium: ($72.66/g). Density 12.41 g/cm3. • Cobalt: ($ 81.50/kg). Density 8.90 g/cm3.

• Platinum: ($28.56/g). Density 21.45 g/cm3. Strong. • Palladium: ($ 31.85/g). Density 12.023 g/cm3

• Cobalt: ($81.50/kg). Density 8.90 g/cm3. • Copper: ($ 7.20/kg). Density 8.96 g/cm3. Weak.

• Cerium: ($5.51/kg). Density 6.770 g/cm3. Weak. • Iron: ($ 71/t for ore). Density 7.874 g/cm3. Weak.

# Production:

Sadly, the only way to produce all this usances use the same compounds that they produce or with other very difficult to get, that means a circular reference. So you must bring it from Earth.

I am kind a fan of a low presure pure oxygen environment which already mentioned.

So you may use solidified oxygen. In the space there is no need to active cooling. You may keep it with simple insulation and a reflective wrapping from radiant heat sources (like sun) and from the rest of your spaceship.

In fact in the failed Apollo 13 misson there is a malfunctioning "heater" that keeps oxygen from solidification.

Or

You may use hydrogen peroxide H2O2. It's a liquid under the room temprature.

You may even transport it in the solid form (it's melting point is very close to water-ice).

For safety reasons it is usually mixed with water.

It's also used as a propellant in the rockets and the jetpacks.

With the silver catalyst, H2O2 very rapidly breaks up (bursts) to water vapour and a oxygen.

Personal Jetpacks used this reaction for a propulsion.