The Martian

Right now, I can go 86km (because I couldn’t get a full battery yesterday). I’m going to leave a solar cell here and drive 40km due south. Then I’ll drop off another solar cell and drive another 40km due south. I’ll have three points of reference across 80km.

The next day, I’ll go back to collect the cells and get the data. By comparing the wattage at the same time of day in those three locations, I’ll learn the shape of the storm. If the storm is thicker to the south, I’ll go north to get around it. If it’s thicker north, I’ll go south.

I’m hoping to go south. Schiaparelli is southeast of me. Going north would add a lot of time to my total trip.

There’s one slight problem with my plan: I don’t have any way to “record” the wattage from an abandoned solar cell. I can easily track and log wattage with the rover computer, but I need something I can drop off and leave behind. I can’t just take readings as I drive along. I need readings at the same time in different places.

So I’m going to spend today working on some mad science. I have to make something that can log wattage. Something I can leave behind with a single solar cell.

Since I’m stuck here for the day anyway, I’ll leave the solar cells out. I may as well get a full battery out of it.

LOG ENTRY: SOL 477

It took all day yesterday and today, but I think I’m ready to measure this storm.

When I packed for this road trip, I made sure to bring all my kits and tools. Just in case I had to repair the rover en-route.

I made the bedroom in to a lab. I stacked my supply containers to form a rudimentary table, and used a sample box as a stool.

I needed a way to track the time of day and the wattage of the solar cell. The tricky part is logging it. And the solution is the extra EVA suit I brought along.

The cool thing about EVA suits is they have cameras recording everything they see. There’s a camera on the right arm (or the left if the astronaut is left handed), and one above the faceplate. A time-stamp is burned in to the lower left corner of the image, just like the shaky home videos Dad used to take.

My electronics kit has several power meters. So I figure: why make my own logging system? I can just film the power meter all day long.

So that’s what I set up.

First, I harvested the cameras from my spare EVA suit. I had to be careful; I didn’t want to ruin the suit. It’s my only spare. I had to get the cameras and the lines leading to their memory chips.

I put a power meter in to a small sample container, then glued a camera to the underside of the lid. When I sealed up the container, the camera was properly recording the readout of the power meter.

For testing, I used rover power. How will it get power once I abandon it on the surface? Well, it turns out it’s going to be attached to a 2 square meter solar cell. That’ll be plenty. And I put a small rechargeable battery in the container to tide it over during nighttime (again, harvested from the spare EVA suit).

The next problem is heat, or the lack thereof. As soon as I take this thing out of the rover, it’ll start cooling down mighty fast. Once it gets too cold, the electronics will stop working entirely.

So I needed a heat source. And my electronics kit provided the answer. Resistors. Lots and lots of them. The camera and power meter only need a tiny fraction of what a solar cell can make. So I’m dumping the rest of the energy through resistors.

Resistors heat up. It’s what they do. There’s my heat source.

I made and tested two “power loggers”, and confirmed the images were being properly recorded.

Then I had an EVA. I detached two of my solar cells and hooked them up to the power loggers. I let them log happily for an hour, then brought them back in to check the results. They worked great.

It’s getting toward nightfall now. Tomorrow morning, I’ll leave one power logger behind, and head south.

While I was working, I left the Oxygenator going (why not?). So I’m all stocked up on O₂ and good to go.

The solar cell efficiency for today was 92.5%. Compared to yesterday’s 97%. So right now, the storm is moving at 4.5% per sol. If I were to stay here another 16 sols, it would get dark enough to kill me.

Just as well I’m not going to stay here.

LOG ENTRY: SOL 478

Everything went as planned today. No hiccups. I can’t tell if I’m driving deeper in to the storm or out of it. It’s hard to tell if the ambient light is less or more than it was yesterday. The human brain works hard to abstract that out.

I left a power-logger behind when I started out. Then, after 40km travel due south, I had a quick EVA to set up another. Now I’ve gone the full 80km, set up my solar cells for charging, and I’m logging the wattage.

Tomorrow, I’ll have to reverse course and pick up the power-loggers. It may be dangerous; I’ll be driving right back in to a known storm area. But the risk is worth the gain.