Chapter 7 #3
I spent the rest of the day vandalizing the interior of the rover.
The pressure compartment is made of carbon composite.
Just inside that is insulation, which is covered by hard plastic.
I used a sophisticated method to remove sections of plastic (hammer), then carefully removed the solid foam insulation (hammer again).
After tearing out some insulation, I suited up and took the RTG outside. Soon, the rover cooled down again, and I brought it back in. I watched as the temperature rose slowly. Nowhere near as fast as it had on my trip back from the burial site.
I cautiously removed more insulation (hammer) and checked again.
After a few more cycles of this, I had enough insulation torn out that the RTG could barely keep up with it.
In fact, it was a losing battle. Over time, heat will slowly leach out.
That’s fine. I can turn on the heater for short bursts when necessary.
I brought the insulation pieces with me back into the Hab. Using advanced construction techniques (duct tape), I reassembled some of them into a square. I figure if things ever get really cold, I can tape that to a bare patch in the rover, and the RTG will be winning the “heat fight.”
Tomorrow, Sirius 3 (which is just Sirius 1 again, but without freezing).
LOG ENTRY: SOL 70
Today, I write to you from the rover. I’m halfway through Sirius 3 and things are going well.
I set out at first light and drove laps around the Hab, trying to stay on untouched ground. The first battery lasted just under two hours. After a quick EVA to switch the cables, I got back to driving. When all was said and done, I had driven 81 kilometers in 3 hours and 27 minutes.
That’s very good! Mind you, the land around the Hab is really flat, as is all of Acidalia Planitia. I have no idea what my efficiency would be on the nastier land en route to Ares 4.
The second battery still had a little juice left, but I can’t just run it down all the way before I stop; remember, I need life support while recharging.
The CO 2 gets absorbed through a chemical process, but if the fan that pushes it isn’t working, I’ll choke.
The oxygen pump is also kind of important.
After my drive, I set up the solar cells. It was hard work; last time I had Vogel’s help. They aren’t heavy, but they’re awkward. After setting up half of them, I figured out I could drag them rather than carry them, and that sped things up.
Now I’m just waiting for the batteries to recharge. I’m bored, so I’m updating the log. I have all the Poirot books in my computer. That’ll help. It’s going to take twelve hours to recharge, after all.
What’s that, you say? Twelve hours is wrong? I said thirteen hours earlier? Well, my friend, let me set you straight.
The RTG is a generator . It’s a paltry amount of power, compared to what the rover consumes, but it’s not nothing. It’s one hundred watts. It’ll cut an hour off my total recharge time. Why not use it?
I wonder what NASA would think about me fucking with the RTG like this. They’d probably hide under their desks and cuddle with their slide rules for comfort.
LOG ENTRY: SOL 71
As predicted, it took twelve hours to charge the batteries to full. I came straight home as soon as they were done.
Time to make plans for Sirius 4. And I think it’ll be a multiday field trip.
Looks like power and battery recharging are solved. Food’s not a problem; there’s plenty of space to store things. Water’s even easier than food. I need two liters per day to be comfortable.
When I do my trip to Ares 4 for real, I’ll need to bring the oxygenator. But it’s big and I don’t want to screw with it right now. So I’ll rely on O 2 and CO 2 filters for Sirius 4.
CO 2 isn’t a problem. I started this grand adventure with 1500 hours of CO 2 filters, plus another 720 for emergency use.
All systems use standard filters (Apollo 13 taught us important lessons).
Since then, I’ve used 131 hours of filter on various EVAs.
I have 2089 left. Eighty-seven days’ worth. Plenty.
Oxygen’s a little trickier. The rover was designed to support three people for two days, plus some reserve for safety. So its O 2 tanks can hold enough to last me seven days. Not enough.
Mars has almost no atmospheric pressure.
The inside of the rover has one atmosphere.
So the oxygen tanks are on the inside (less pressure differential to deal with).
Why does that matter? It means I can bring along other oxygen tanks, and equalize them with the rover’s tanks without having to do an EVA.
So today, I detached one of the Hab’s two 25-liter liquid oxygen tanks and brought it into the rover.
According to NASA, a human needs 588 liters of oxygen per day to live.
Compressed liquid O 2 is about 1000 times as dense as gaseous O 2 in a comfortable atmosphere.
Long story short: With the Hab tank, I have enough O 2 to last 49 days. That’ll be plenty.
Sirius 4 will be a twenty-day trip.
That may seem a bit long, but I have a specific goal in mind. Besides, my trip to Ares 4 will be at least forty days. This is a good scale model.
While I’m away, the Hab can take care of itself, but the potatoes are an issue.
I’ll saturate the ground with most of the water I have.
Then, I’ll deactivate the atmospheric regulator, so it doesn’t pull water out of the air.
It’ll be humid as hell, and water will condense on every surface.
That’ll keep the potatoes well watered while I’m away.
A bigger problem is CO 2 . The potatoes need to breathe. I know what you’re thinking. “Mark, old chap! You produce carbon dioxide! It’s all part of the majestic circle of nature!”
The problem is: Where will I put it? Sure, I exhale CO 2 with every breath, but I don’t have any way to store it. I could turn off the oxygenator and atmospheric regulator and just fill the Hab with my breath over time. But CO 2 is deadly to me. I need to release a bunch at once and run away.
Remember the MAV fuel plant? It collects CO 2 from the Martian atmosphere. A 10-liter tank of compressed liquid CO 2 , vented into the Hab, will be enough CO 2 to do the trick. That’ll take less than a day to create.
So that’s everything. Once I vent the CO 2 into the Hab, I’ll turn off the atmospheric regulator and oxygenator, dump a ton of water on the crops, and head out.
Sirius 4. A huge step forward in my rover research. And I can start tomorrow.