Randall nodded. “Thank you, Dr. Kapoor.” He turned his laptop around to show a map of Mars. “Over the past few weeks, a dust storm has been developing in Arabia Terra. Not a big deal in terms of magnitude. It won’t hinder his driving at all.”

“So what’s the problem?” Annie asked.

“It’s a low-velocity dust storm,” Randall explained. “Slow winds, but fast enough to pick up very small particles on the surface and whip them into thick clouds. There are five or six of them every year. The thing is, they last for months, they cover huge sections of the planet, and they make the atmosphere thick with dust.”

“I still don’t see the problem,” Annie said.

“Light,” Randall said. “The total sunlight reaching the surface is very low in the area of the storm. Right now, it’s twenty percent of normal. And Watney’s rover is powered by solar panels.”

“Shit,” Mitch said, rubbing his eyes. “And we can’t warn him.”

“So he gets less power,” Annie said. “Can’t he just recharge longer?”

“The current plan already has him recharging all day long,” Venkat explained. “With twenty percent of normal daylight, it’ll take five times as long to get the same energy. It’ll turn his forty five-sol trip into two hundred and twenty-five sols. He’ll miss the Hermes flyby.”

“Can’t Hermes wait for him?” Annie asked.

“It’s a flyby,” Venkat said. “Hermes isn’t going into Martian orbit. If they did, they wouldn’t be able to get back. They need their velocity for the return trajectory.”

After a few moments of silence, Teddy said, “We’ll just have to hope he finds a way through. We can track his progress and—”

“No, we can’t,” Mindy interrupted.

“We can’t?” Teddy said.

She shook her head. “The satellites won’t be able to see through the dust. Once he enters the affected area, we won’t see anything until he comes out the other side.”

“Well…,” Teddy said. “Shit.”

LOG ENTRY: SOL 439

Before I risk my life with this contraption, I need to test it.

And not the little tests I’ve been doing so far. Sure, I’ve tested power generation, life support, the trailer bubble, and the bedroom. But I need to test all aspects of it working together.

I’m going to load it up for the long trip and drive in circles. I won’t ever be more than 500 meters from the Hab, so I’ll be fine if shit breaks.

I dedicated today to loading up the rover and trailer for the test. I want the weight to match what it’ll be on the real trip. Plus if cargo is going to shift around or break things, I want to know about it now.

I made one concession to common sense: I left most of my water supply in the Hab. I loaded twenty liters; enough for the test but no more. There are a lot of ways I could lose pressure in this mechanical abomination I’ve created, and I don’t want all my water to boil off if that happens.