Lucky for me, the tech specs for everything are right here in the computer.
I’ll need to trick out a rover. Basically it’ll have to be a mobile Hab. I’ll pick Rover 2 as my target. We have a certain bond, after I spent two days in it during the “Great Hydrogen Scare of Sol 37.”
There’s too much shit to think about all at once. So for now, I’ll just think about power.
Our mission had a 10km operational radius. Knowing we wouldn’t take straight-line paths, NASA designed the rovers to go 35km on a full charge. That presumes flat, reasonable terrain. Each rover has a 9000Wh battery.
Step one is to loot Rover 1’s battery and install it in Rover 2. Ta-daa! I just doubled my full-charge range.
There’s just one complication. Heating.
Part of the battery power goes to heating the rover. Mars is really cold. Normally, we were expected to do all EVAs in under 5 hours. But I’ll be living in it 24½ hours a day. According to the specs, the heating equipment soaks up 400W. Keeping it on would eat up 9800Wh per day. Over half my power supply, every day!
But I do have a free source of heat: Me. A couple million years of evolution gave me “warm blooded” technology. I can wear layers. The rover has good insulation, too. It’ll have to be enough; I need every bit of power.
And because I need to bundle up anyway, I can deactivate the heater outright and use all the power for motion (minus a negligible amount for computer, life support, etc.)
According to my boring math, moving the rover eats 200Wh of juice to go 1km, so using the full 18,000Wh gets me 90km of travel. Now we’re talkin’.
I’ll never actually get 90km on a single charge. I’ll have hills to deal with, and rough terrain, sand, etc. But it’s a good ballpark. It tells me that it would take at least 35 days of travel to get to Ares 4. It’ll probably be more like 50. But that’s plausible, at least.
At the rover’s blazing 25kph top speed, it’ll take me 3½ hours before I run the battery down. I’d like to charge the battery up during the rest of the day. I can drive in twilight, and save the sunny part of the day for charging. This time of year I get about 13 hours of light. How many solar cells will I have to pilfer from the Hab’s farm?
Thanks to the fine taxpayers of America, I have over 100 of square meters of the most expensive solar paneling ever made. It has an astounding 10.2% efficiency, which is good because Mars doesn’t get as much sunlight as Earth. Only 500 to 700 watts per square meter (Compared to the 1400 those spoiled Earthlings get).
Long story short: I need to bring 28 square meters of solar cell. That’s 14 panels.
I can put two stacks of 7 on the roof. They’ll stick out over the edges, but as long as they’re secure I’m happy. Every day, after driving, I’ll spread them out then… wait all day. Man it’ll be dull.
Well it’s a start. Tomorrow’s mission: transfer Rover 1’s battery to Rover 2.
LOG ENTRY: SOL 64
Sometimes things are easy, and sometimes they’re not. Getting the battery out of Rover 1 was easy. I removed two clamps on the undercarriage and it dropped right out. The cabling is easy to detach, too. It’s just a couple of complicated plugs.
Attaching it to Rover 2, however, is another story. There’s nowhere to put it!
The things is huge. I was barely able to drag it. And that’s in Mars gravity.
It’s just too big. There’s no room in the undercarriage for a second one. There’s no room on the roof, either. That’s where the solar cells will go. There’s no room inside the cabin, and it wouldn’t fit through the airlock anyway.
But fear not, I found a solution.
For emergencies completely unrelated to this one, NASA provided 6 square meters of Hab canvas, and some really impressive resin. The same kind of resin, in fact, that saved my life on Sol 6 (the patch kit I used on the hole in my suit).
In the event of a Hab breach, everyone would run to the airlocks. Procedure was to let it pop rather than die trying to prevent it. Then, we’d suit up and assess the damage. Once we found the breach, we’d seal it with the spare Hab canvas and resin. Then re-inflate and we’re good as new.
The 6 square meters of spare canvas was a convenient 1x6 meters. I cut 10cm wide strips, then used them to make a sort of harness.
I used the resin and straps to make two 10m circumference loops. Then I put a big patch of canvas on each end. I now had poor-man’s saddlebags for my rover.
This is getting more and more “Wagon Train” every day.
The resin sets almost instantly. But it gets stronger if you wait an hour. So I did. Then I suited up and headed out to the rover.
I dragged the battery to the side of the rover and looped one end of the harness around it. Then I threw the other end over the roof. On the other side, I filled it with rocks. When the two weights were roughly equal, I was able to pull the rocks down and bring the battery up.
Yay!
Unplugging Rover 2’s battery, I plugged in Rover 1’s. Then I went through the airlock to the rover and checked all systems. Everything was a-ok.
I drove the rover around a bit to make sure the harness was secure. I found a few large-ish rocks to drive over, just to shake things up. The harness held. Hell yeah.
For a short time, I wondered how to splice the second battery’s leads into the main power supply. My conclusion was “Fuck it.”
There’s no need to have a continuous power supply. When Battery 1 runs out, I can get out, unplug Battery 1 and plug in Battery 2. Why not? It’s a 10 minute EVA, once per day. I’d have to swap batteries again when charging, but again: so what?
I spent the rest of the day sweeping off the solar cell farm. Soon, I shall be looting it.
LOG ENTRY: SOL 65
The solar cells were a lot easier to manage than the battery.
They’re thin, light, and just laying around on the ground. And I had one additional bonus: I was the one who set them up In the first place.
Well, ok. It wasn’t just me. Vogel and I worked together on it. And boy did we drill on it. We spent almost an entire week drilling on the solar array alone. Then we drilled more whenever they figured we had spare time. It had been deemed mission critical. If we fucked it up and broke the cells or rendered them useless, the Hab wouldn’t be able to make power, and the mission would end.
You might wonder what the rest of the crew were doing. They were setting up the Hab. Remember, everything in my glorious kingdom came here in boxes. We had to set it up on Sols 1 and 2.
Each solar cell is on a lightweight lattice that holds it at a 14 degree angle. I’ll admit I don’t know why it’s a 14 degree angle. Something about maximizing solar energy. Anyway, removing the cells was simple. Then it was time to stack them on the rover.