He went around the smaller dunes, and carefully crested the larger ones. He took care with every turn, every rise or fall in elevation, and every boulder in his path. He thought through every course and considered all alternatives.

But it wasn't enough.

The rover, while descending down a seemingly ordinary slope, drove off an invisible ridge. The dense, hard soil suddenly gave way to soft powder. With the entire surface covered by at least 5cm of dust, there were no visual hints to the sudden change.

The rover's left front wheel sank. The sudden tilt brought the right rear wheel completely off the ground. This in turn put more weight on the left rear wheel, which slipped from it's precarious purchase into the powder as well.

Before the traveler could react, the rover rolled on to its side. As it did, the solar cells neatly stacked on the roof flew off and scattered like a dropped deck of cards.

The trailer, attached to the rover with a tow clamp, was dragged along. The torsion on the clamp snapped the strong composite like a brittle twig. The hoses connecting the two vehicles also snapped. The trailer plunged head-long in to the soft soil and flipped over on to its balloon-roof, shuddering to an abrupt halt.

The rover was not so lucky. It continued tumbling down the hill, bouncing the traveler around like clothes in a dryer. After 20 meters, the soft powder gave way to more solid sand and it shuddered to a halt.

The rover had come to rest on its side. The valves leading to the now missing hoses had detected the sudden pressure drop and closed. The pressure seal was not breached.

The traveler was alive for now.

Chapter 24

The department heads stared at the satellite image on the projection screen.

"Jesus," Mitch said. "What the hell happened?"

"The rover's on its side," Mindy said, pointing to the screen. "The trailer's upside down. Those rectangles scattered around are solar cells."

Venkat put a hand on his chin. "Do we have any information on the state of the rover pressure vessel?"

"Nothing obvious," Mindy said.

"Any signs of Watney doing something after the accident? An EVA maybe?"

"No EVA," Mindy said. "The weather's clear. If he'd come out there'd be visible footsteps."

"Is this the entire crash site?" Bruce Ng asked.

"I think so," Mindy said. "Up toward the top of the photo, which is North, there are ordinary wheel tracks. Right here," she pointed to a large disturbance in the soil, "is where I think things went wrong. Judging by where that ditch is, I'd say the rover rolled and slid from there. You can see the trench it left behind. The trailer flipped forward on to its roof."

"I'm not saying everything's ok," Bruce said, "but I don't think it's as bad as it looks."

"Go on," Venkat said.

"The rover's designed to handle a roll," Bruce explained. "And if there'd been pressure loss there'd be a starburst pattern in the sand. I don't see anything like that."

"Watney may still be hurt inside," Mitch said. "He could have banged his head or broken an arm or something."

"Sure," Bruce said. "I'm just saying the rover is probably ok."

"When was this taken?"

Mindy checked her watch. "We got it 17 minutes ago. We’ll get another pic in 9 minutes when MGS4’s orbit brings it in view.”

“First thing he’ll do is an EVA to assess damage,” Venkat said. “Mindy, keep us posted on any changes.”

LOG ENTRY: SOL 498

Hmm.

Yeah.

Things don't go well on the descent in to Schiaparelli Basin. To give you some indication of how unwell they went, I'm reaching up to the computer to type this. Because it's still mounted near the control panel, and the rover is on its side.

I got bounced around a lot, but I'm a well-honed machine in times of crisis. As soon as the rover toppled, I curled in to a ball and cowered. That's the kind of action hero I am.

It worked, too. Cause I'm not hurt.

The pressure vessel is intact, so that's a plus. The valves that lead to the trailer hoses are shut. Probably means the hoses disconnected. And that means the trailer junction snapped. Wonderful.

Looking around the interior here, I don't think anything is broken. The water tanks stayed sealed. There aren't any visible leaks in the air tanks. The bedroom came unfolded and it's all over the place, but it's just canvas so it can't have gotten too hurt.

The driving controls are ok, and the Nav Computer is telling me the rover is at an "unacceptably dangerous tilt." Thanks, Nav!

So I rolled. That's not the end of the world. I'm alive and the rover's fine. I'm more worried about the solar cells I probably rolled over. Also, since the trailer detached there's a good chance it's fucked up, too. The balloon roof it has isn't exactly durable. If it popped, the shit inside will have flung out in all directions and I'll have to go find it. That's my critical life support.

Speaking of life support, the rover switched over to the local tanks when the valves shut. Good boy, Rover! Here's a Scooby-Snack.

I've got 20L of oxygen (enough to keep me breathing for 40 days) but without the Regulator (which is in the trailer) I'm back to chemical CO2 absorption. I have 312 hours of filters left. Plus I have another 171 hours of EVA suit CO2 filters as well. All told, they'll last 483 hours, which is close to 20 sols. So I have time to get things working again.

I'm really damn close to the MAV now. About 220km. I'm not going to let something like this stop me from getting there. And I don't need everything to work at top form anymore. I just need the rover to work for 220 more kilometers and the life support to work for 51 more sols. That's it.

Time to suit up and look for the trailer.

LOG ENTRY: SOL 498 (2)

I had an EVA and things aren't too bad. Mind you, they're not good.

I trashed 3 solar cells. They're under the rover and cracked all to hell. They might still be able to piss out out a few watts, but I'm not holding out much hope. I did come in to this with one extra solar cell. I needed 28 for my daily operations and I brought 29 (14 on the rover's roof, 7on the trailer's roof, and 8 on the makeshift shelves I installed on the sides of both vehicles.)

I tried pushing the rover over, but I wasn't strong enough. I'll need to rig something to get a leverage advantage. Other than being on its side, I don't see any real problems.

Well, that's not true. The tow hook is fucked beyond repair. Half of it ripped clean off. Fortunately, the trailer also has a tow hook, so I have a spare.

The trailer's in a precarious situation. It's upside-down and sitting on the inflated roof. I'm not sure which god smiled down on me and kept that balloon from popping, but I'm grateful. My first priority will be righting it. The longer it puts weight on that balloon, the  larger the chances it'll pop.