The Martian

More accurately, Sirius 1 was aborted after 1 hour. I guess you could call it a “failure” but I prefer the term “learning experience.”

Things started out fine. I drove to a nice flat spot a kilometer from the Hab, then started going back and forth over a 500m stretch.

I quickly realized this would be a crappy test. After a few laps, I had compressed the soil enough to have a solid path. Nice, hard ground, which makes for abnormally high energy efficiency. This is nothing like it would be on a long trip.

So I shook it up a bit. I drove around randomly, making sure to stay within a kilometer of the Hab. A much more realistic test.

After an hour, things started to get cold. And I mean really cold.

The rover’s always cold when you first get in it. When you haven’t disabled the heater it warms up right away. I expected it to be cold, but Jesus Christ!

I was fine for a while. My own body heat plus three layers of clothing kept me warm and the rover’s insulation is top-notch. The heat that escaped my body just warmed up the interior. But there’s no such thing as perfect insulation, and eventually the heat left to the great outdoors while I got colder and colder.

Within an hour, I was chattering and numb. Enough was enough. There’s no way I could do a long trip like this. The test was over.

Turning the heater on, I drove straight back to the Hab.

Once I got home, I sulked for a while. All my brilliant plans foiled by thermodynamics. Damn you, Entropy!

I’m in a bind. The damn heater will eat half my battery power every day. I could turn it down, I guess. Be a little cold but not freezing to death. Even then I’d still lose at least a quarter.

This will require some thought. I have to ask myself… what would Hercule Poirot do? I’ll have to put my “little gray cells” to work on the problem.

LOG ENTRY: SOL 68

Well shit.

I came up with a solution, but… remember when I burned rocket fuel in the Hab? This’ll be more dangerous.

I’m going to use the RTG.

The RTG (Radioisotope Thermoelectric Generator) is a big box of Plutonium. But not the kind used in nuclear bombs. No, no. This Plutonium is way more dangerous!

Plutonium-238 is an incredibly unstable isotope. It’s so radioactive that it will get red hot all by itself. As you can imagine, a material that can literally fry an egg with radiation is kind of dangerous.

The RTG houses the Plutonium, catches the radiation in the form of heat, and turns it in to electricity. It’s not a reactor. The radiation can’t be increased or decreased. It’s a purely natural process happening at the atomic level.

As long ago as the 1960’s, NASA’s been using RTGs to power unmanned probes. It has lots of advantages over solar power. It’s not affected by storms; it works day or night; it’s entirely internal, so you don’t need delicate solar cells all over your probe.

But they never used large RTGs on manned missions until The Ares Program.

Why not? It should be pretty fucking obvious why not! They didn’t want to put astronauts next to a glowing hot ball of radioactive death!

I’m exaggerating a little. The Plutonium is inside a bunch of pellets, each one sealed and insulated to prevent radiation leakage even if the outer container is breached. So for the Ares Program, they took the risk.

An Ares mission is all about the MAV. It’s the single most important component. It’s one of the few systems that can’t be replaced or worked around. It’s the only component that causes a complete mission scrub if it’s not working.

Solar cells are great in the short-term, and they’re good for the long-term if you have humans around to clean them. But the MAV sits alone for years quietly making fuel, then just kind of hangs out until its crew arrives. Even doing nothing, it needs power, so NASA can monitor it remotely and run self checks.

The prospect of scrubbing a mission because a solar cell got dirty was unacceptable. They needed a more reliable source of power. So the MAV comes equipped with an RTG. It has 2.6kg of Plutonium-238, which makes almost 1500 Watts of heat. It can turn that in to 100 Watts of electricity. The MAV runs on that until the crew arrive.

100 Watts isn’t enough to keep the heater going, but I don’t care about the electrical output. I want the heat. A 1500 Watt heater is so warm I’ll have to tear insulation out of the rover to keep it from getting too hot.

As soon as the rovers were un-stowed and activated, Commander Lewis had the joy of disposing of the RTG. She detached it from the MAV, drove 4 km away, and buried it. However safe it may be, it’s still a radioactive core and NASA didn’t want it too close to their astronauts.

The mission parameters don’t give a specific location to dump the RTG. Just “At least 4km away”. So I’ll have to find it.