Over time, the solar panels get covered with dust. Then winter brings colder temperatures and less daylight. This all combines into a big “fuck you” from Mars to your lander. Eventually it’s using more power to keep warm than it’s getting from the meager daylight that makes it through the dust.

Once the battery runs down, the electronics get too cold to operate, and the whole system dies. The solar panels will recharge the battery somewhat, but there’s nothing to tell the system to reboot. Anything that could make that decision would be electronics, which would not be working. Eventually, the now-unused battery will lose its ability to retain charge.

That’s the usual cause of death. And I sure hope it’s what killed Pathfinder.

I piled some leftover parts of the MDV into a makeshift table and ramp. Then I dragged the lander up to my new outdoor workbench. Working in an EVA suit is annoying enough. Bending over the whole time would have been torture.

I got my tool kit and started poking around. Opening the outer panel wasn’t too hard and I identified the battery easily enough. JPL labels everything. It’s a 40 amp-hour Ag-Zn battery with an optimal voltage of 1.5. Wow. They really made those things run on nothin’ back then.

I detached the battery and headed back inside. I checked it with my electronics kit, and sure enough it’s dead, dead, dead. I could shuffle across a carpet and hold more charge.

But I knew what the lander needed: 1.5 volts.

Compared to the makeshift crap I’ve been gluing together since Sol 6, this was a breeze. I have voltage controllers in my kit! It only took me fifteen minutes to put a controller on a reserve power line, then another hour to go outside and run the line to where the battery used to be.

Then there’s the issue of heat. It’s a good idea to keep electronics above −40°C. The temperature today is a brisk −63°C.

The battery was big and easy to identify, but I had no clue where the heaters were. Even if I knew, it’d be too risky to hook them directly to power. I could easily fry the whole system.

So instead, I went to good old “Spare Parts” Rover 1 and stole its environment heater. I’ve gutted that poor rover so much, it looks like I parked it in a bad part of town.

I lugged the heater to my outdoor “workbench,” and hooked it to Hab power. Then I rested it in the lander where the battery used to be.

Now I wait. And hope.

LOG ENTRY: SOL 96

I was really hoping I’d wake up to a functional lander, but no such luck. Its high-gain antenna is right where I last saw it. Why does that matter? Well, I’ll tell ya…

If the lander comes back to life (and that’s a big if), it’ll try to establish contact with Earth. Problem is nobody’s listening. It’s not like the Pathfinder team is hanging around JPL just in case their long-dead probe is repaired by a wayward astronaut.