So I'll need to survive away from the Hab for 100 sols.

“What about the MAV?” I hear you ask (in my fevered imagination). “Won't it have some supplies? Air and water at the very least?”

Nope. It's got dick-all.

It does have air tanks, but they're empty. An Ares mission needs lots of O2, N2 and water anyway. Why send more with the MAV? Easier to have the crew top off the MAV from the Hab. Fortunately for my crewmates, the mission plan had Martinez fill the MAV tanks on Sol 1.

The flyby is on Sol 549, so I'll need to leave by 449. That gives me 257 sols to get my shit in gear.

Seems like a long time, doesn't it?

In that time, I need to modify the rover to carry the Atmospheric Regulator, Oxygenator, and Water Reclaimer. I call them “The Big Three”. All three need to be in the pressurized area, but the rover isn't big enough. All three need to be running at all times, but the rover's batteries can't handle that load for long.

The rover will also need to carry all my food, water, solar cells, extra battery, my tools, some spare parts, and Pathfinder. As my sole means of communication with NASA, Pathfinder gets to ride on the roof, Granny Clampett style.

I have a lot of problems to solve, but I have a lot of smart people to solve them. Pretty much the whole planet Earth.

NASA is still working on the details, but the idea is to use both rovers. One to drive around, the other to act as a trailer for all the shit I have to bring.

I'll have to make structural changes to that trailer. And by “structural changes” I mean “cut a big hole in the hull.” Then I can move the Big Three in and use Hab canvas to loosely cover the hole. It'll balloon out when I pressurize the rover, but it'll hold.

How will I cut a big chunk out of a rover's hull? I'll let my lovely assistant Venkat Kapoor explain further:

[14:38]JPL: I'm sure you're wondering how to cut a hole in the rover.

Our experiments show a rock sample drill can get through the hull. Wear and tear on the bit is minimal (rocks are harder than carbon composite). You can cut holes in a line, then chisel out the remaining chunks between them.

I hope you like drilling. The drill bit is 1cm wide, the holes will be 0.5cm apart, and the length of the total cut is 11.4m. That's 760 holes. And each one takes 160 seconds to drill.

Problem: The drills weren't designed for construction projects. They were intended for quick rock samples. The batteries only last 240 seconds. You do have two drills, but you'd still only get 3 holes done before needing to recharge. And recharging takes 41 minutes.

That's 173 hours of work, limited to 8 EVA hours per day. That's 21 days of drilling, and that's just too long. All our other ideas hinge on this cut working. If it doesn't, we need time to come up with new ones.

So we want you to wire a drill directly to Hab power.

The drill expects 28.8V and pulls 9 Amps. The only lines that can handle that are the rover recharge lines. They're 36V, 10A max. Since you have two, we're comfortable with you modifying one.

We'll send you instructions on how to step down the voltage and put a new breaker in the line, but I'm sure you already know how.

I'll be playing with high voltage power tomorrow. Can't imagine anything going wrong with that!

LOG ENTRY: SOL 193

I managed to not kill myself today, even though I was working with high voltage. Well, it's not as exciting as all that. I disconnected the line before I fucked with it.

As instructed, I turned a rover charging cable into a drill power source. Getting the voltage was a simple matter of adding resistors, which my electronics kit has in abundance.

I had to make my own a 9 Amp breaker. I strung three 3A breakers in parallel. There's no way for 9A to get through that without tripping all three in rapid succession.

Then I had to rewire a drill. Pretty much the same thing I did with Pathfinder. Take out the battery and replace it with a power line from the Hab. But this time it was a lot easier.

Pathfinder was too big to fit through any of my airlocks, so I had to do all the rewiring outside. Ever done electronics while wearing a space suit? Pain in the ass. I even had to make a workbench out of MAV landing struts, remember?

Anyway, the drill fit in the airlock easily. It's only a meter tall, and shaped like a jackhammer. We did our rock sampling standing up, like Apollo astronauts.

Also, unlike my Pathfinder hatchet-job, I had the full schematics of the drill. I removed the battery and attached a power line where it used to be. Then, taking the drill and it's new cord outside, I connected it to the modified rover charger and fired it up.

Worked like a charm! The drill whirled away with happy abandon. Somehow, I had managed to do everything right the first try. Deep down, I thought I'd fry the drill for sure.

It wasn't even midday yet. I figured why not get a jump on drilling?

[10:07] Watney: Power line modifications complete. Hooked it up to a drill, and it works great. Plenty of daylight left. Send me a description of that hole you want me to cut.

[10:25] JPL: Glad to hear it. Starting on the cut sounds great. Just to be clear, these are modifications to Rover 1, which we've been calling “the trailer.” Rover 2 (the one with your modifications for the trip to Pathfinder) should remain as-is for now.

You'll be taking a chunk out of the roof, just in front of the airlock in the rear of the vehicle. The hole needs to be at least 2.5m long and the full 2m width of the pressure vessel.

Before any cuts, draw the shape on the trailer, and position the trailer where Pathfinder's camera can see it. We'll let you know if you got it right.

[10:43] Watney: Roger. Take a pic at 11:30 if you haven't heard from me by then.

The rovers are made to interlock so one can tow the other. That way you can rescue your crewmates if the shit hits the fan. For that same reason, rovers can share air via hoses you connect between them. That little feature will let me share atmosphere with the trailer on my long drive.

I'd stolen the trailer's battery long ago; it had no ability to move under it's own power. So I hitched it up to my awesomely modified rover and towed it in to place near Pathfinder.

Venkat told me to “draw” the shape I plan to cut, but he neglected to mention how. It's not like I have a Sharpie that can work out on the surface. So I vandalized Martinez's bed.

The cots are basically hammocks. Lightweight string woven loosely into something that's comfortable to sleep on. Every gram counts when making stuff to send to Mars.

I unraveled Martinez's bed and took the string outside. I taped it to the trailer hull along the path I planned to cut. Yes, of course duct tape works in a near-vacuum. Duct tape works anywhere. Duct tape is magic and should be worshiped.