But I can’t get it to do that for hydrogen, because hydrogen needs to be below 21K to turn liquid. And the regulator just can’t get temperatures that low. Dead end.

Here’s the solution:

Hydrogen is dangerous because it can blow up. But it can only blow up if there’s oxygen around. Hydrogen without oxygen is harmless. And the regulator is all about pulling oxygen out of the air.

There are four different safety interlocks that prevent the regulator from letting the Hab’s oxygen content get too low. But they’re designed to work against technical faults, not deliberate sabotage (bwa ha ha!).

Long story short, I can trick the regulator into pulling all the oxygen out of the Hab. Then I can wear a space suit (so I can breathe) and do whatever I want without fear of blowing up.

I’ll use an O₂ tank to spray short bursts of oxygen at the hydrogen, and make a spark with a couple of wires and a battery. It’ll set the hydrogen on fire, but only until the small bit of oxygen is used up.

I’ll just do that over and over, in controlled bursts, until I’ve burned off all the hydrogen.

One tiny flaw with that plan: It’ll kill my dirt.

The dirt is only viable soil because of the bacteria growing in it. If I get rid of all the oxygen, the bacteria will die. I don’t have 100 billion little space suits handy.

It’s half a solution anyway.

Time to take a break from thinking.

Commander Lewis was the last one to use this rover. She was scheduled to use it again on Sol 7, but she went home instead. Her personal travel kit’s still in the back. Rifling through it, I found a protein bar and a personal USB, probably full of music to listen to on the drive.

Time to chow down and see what the good commander brought along for music.

LOG ENTRY SOL 38 (2)

Disco. God damn it, Lewis.

LOG ENTRY: SOL 39

I think I’ve got it.

Soil bacteria are used to winters. They get less active, and require less oxygen to survive. I can lower the Hab temperature to 1°C, and they’ll nearly hibernate. This sort of thing happens on Earth all the time. They can survive a couple of days this way. If you’re wondering how bacteria on Earth survive longer periods of cold, the answer is they don’t. Bacteria from further underground where it is warmer breed upward to replace the dead ones.

They’ll still need some oxygen, but not much. I think a 1 percent content will do the trick. That leaves a little in the air for the bacteria to breathe, but not enough to maintain a fire. So the hydrogen won’t blow up.

But that leads to yet another problem. The potato plants won’t like the plan.

They don’t mind the lack of oxygen, but the cold will kill them. So I’ll have to pot them (bag them, actually) and move them to a rover. They haven’t even sprouted yet, so it’s not like they need light.