Generating Air / Oxygen

The ISS uses magnet monopoles to create a magnet funnel, which can scoop up the extremely rarefied oxygen that exists in near earth orbit. This is similar to the idea of a Bussard ramjet, but obviously less sophisticated.

No deliveries of oxygen are required.

I think that would be the least of your worries!

Building a space station presents a huge challenge in sustaining a breathable atmosphere. You have two main approaches: closed-loop air recycling and regular resupply missions. A combination of both is typically the most practical.

1. Methods for Generating and Recycling Breathable Air A space station must maintain a mix of approximately 21% oxygen and 78% nitrogen at 1 atmosphere (14.7 psi) or lower for human comfort. Here’s how you can generate and recycle breathable air:

A. Oxygen Generation

1. Electrolysis of Water (Primary Method)

- Uses electricity (usually from solar panels) to split H2O into O2 and H2.

- The O2 is released into the crew cabin.

- The H2 is usually vented into space or used in a Sabatier reaction (see below).

- Example: NASA’s Oxygen Generation Assembly (OGA) on the ISS.

1. Chemical Oxygen Candles (Backup)

- Solid oxygen generators like "chlorate candles" or "peroxide-based candles".

- Used as emergency oxygen sources.

- Example: Vika system on Russian spacecraft.

1. Stored or Delivered Oxygen (Backup)

- Oxygen tanks or liquid oxygen can be periodically resupplied.

- This is not sustainable for long-term missions but serves as a backup.

B. Carbon Dioxide Removal

Exhaled air contains CO2, which must be removed to avoid poisoning the crew. Several methods exist:

1. Lithium Hydroxide (LiOH) Scrubbers (Consumable)

- Absorbs CO2 chemically.

- Used in spacecraft like Apollo and early ISS modules.

- Not regenerable, so it requires constant replacement.

1. Molecular Sieve CO2 Scrubbers (Regenerable)

- Uses zeolite materials to absorb CO2, which is later vented into space.

- Example: ISS’s Carbon Dioxide Removal Assembly (CDRA).

1. Sabatier Reaction (Best for Long-Term Missions)

- Reacts carbon dioxide (CO2) with hydrogen (H2) to produce methane (CH4) and water (H2O).

- The water is recycled into the electrolysis system to generate more oxygen.

- Reduces waste and increases efficiency.

- Example: ISS Sabatier System.

- Reaction: CO2 + 4H2 -> CH4 + 2H2O

1. Algae or Plants (Experimental)

- Algae (like Chlorella) or plants can absorb CO2 and produce O2 through photosynthesis.

- NASA has tested plant-based life support, but it requires significant space and light.

- Might be useful for long-term deep-space habitats.

If you suck-up to Putin, maybe he has a couple of warehouses full of new-old-stock oxygen candles he'll let you have?

Chris Holmes snipped-for-privacy@gmail.com wrote in news:vqc5kk$2vs7v$2@dont- email.me:

The kids did this recently in the back garden, the difficulty was getting the cardboard boxes from the supermarket before they were crushed. Oxygenated air appeared to be readily available, perhaps being filtered along the length of the corrugations.

You will have to prize the orange oaf off his butt hole first!

Get it delivered, and then auction off the supplies to the highest bidder amongst the on-board crew. It could be a profitable venture.

There are plenty of icy comets that occasionally get kicked out of the Oort cloud. You can use either electrolysis or photolysis to get the oxygen out.

more a Q for uk.rec.gardening

ala film Silent Running

Amazon. Then tax it.

Didn't early spaceships use an atmosphere of pure Oxygen? I was trying to imagine what that would be like to breathe and to speak.

TW

I think fighter-pilots sometimes use pure oxygen. It makes no difference to speech. I had access to a bottle at work, and it's great for clearing your head after a night on the town. :)

Until one caught fire on the launch pad…

You probably wouldn’t notice any difference. It’s not helium…

Tim

That's because it was at 20 psi to simulate the condition in space when it would be at 5 psi. Almost anything will burn in oxygen at that pressure.

Not after Apollo 1 they didn't.

Yes, they did. It accelerated the combustion of the flammable contents of the first Apollo space capsule in 1967 and resulted in the deaths of three astronauts during a practice run.

Velocities of sound in various gases: Air 331m/sec. Oxygen 330m/sec. Helium 973m/sec.

Back in the '80s, our deputy-headmaster/chemistry teacher, used to breath the Oxygen from the bottle at the front of the lab, during lessons. He did have an alcohol problem and took some months off drying out.

Inhaling Helium a noble gas.

Hydrogen? Don’t you mean helium? Certainly much easier for Joe Public to get hold of.

Tim