Chapter 22
Mawrth Vallis! I’m finally here!
Actually, it’s not an impressive accomplishment. I’ve only been traveling ten sols. But it’s a good psychological milestone.
So far, the rover and my ghetto life support are working admirably. At least, as well as can be expected for equipment being used ten times longer than intended.
Today is my second Air Day (the first was five sols ago). When I put this scheme together, I figured Air Days would be godawful boring. But now I look forward to them. They’re my days off.
On a normal day, I get up, fold up the bedroom, stack the solar cells, drive four hours, set up the solar cells, unfurl the bedroom, check all my equipment (especially the rover chassis and wheels), then make a Morse code status report for NASA, if I can find enough nearby rocks.
On an Air Day, I wake up and turn on the oxygenator.
The solar panels are already out from the day before.
Everything’s ready to go. Then I chill out in the bedroom or rover.
I have the whole day to myself. The bedroom gives me enough space that I don’t feel cooped up, and the computer has plenty of shitty TV reruns for me to enjoy.
Technically, I entered Mawrth Vallis yesterday. But I only knew that by looking at a map. The entrance to the valley is wide enough that I couldn’t see the canyon walls in either direction.
But now I’m definitely in a canyon. And the bottom is nice and flat. Exactly what I was hoping for. It’s amazing; this valley wasn’t made by a river slowly carving it away. It was made by a mega-flood in a single day. It would have been a hell of a thing to see.
Weird thought: I’m not in Acidalia Planitia anymore. I spent 457 sols there, almost a year and a half, and I’ll never go back. I wonder if I’ll be nostalgic about that later in life.
If there is a “later in life,” I’ll be happy to endure a little nostalgia. But for now, I just want to go home.
■■■
“Welcome back to CNN’s Mark Watney Report ,” Cathy said to the camera. “We’re speaking with our frequent guest, Dr. Venkat Kapoor. Dr. Kapoor, I guess what people want to know is, is Mark Watney doomed?”
“We hope not,” Venkat responded, “but he’s got a real challenge ahead of him.”
“According to your latest satellite data, the dust storm in Arabia Terra isn’t abating at all, and will block eighty percent of the sunlight?”
“That’s correct.”
“And Watney’s only source of energy is his solar panels, correct?”
“Yes, that’s right.”
“Can his makeshift rover operate at twenty percent power?”
“We haven’t found any way to make that happen, no. His life support alone takes more energy than that.”
“How long until he enters the storm?”
“He’s just entered Mawrth Vallis now. At his current rate of travel, he’ll be at the edge of the storm on Sol 471. That’s twelve days from now.”
“Surely he’ll see something is wrong,” Cathy said. “With such low visibility, it won’t take long for him to realize his solar cells will have a problem. Couldn’t he just turn around at that point?”
“Unfortunately, everything’s working against him,” Venkat said.
“The edge of the storm isn’t a magic line.
It’s just an area where the dust gets a little more dense.
It’ll keep getting more and more dense as he travels onward.
It’ll be really subtle; every day will be slightly darker than the last. Too subtle to notice. ”
Venkat sighed. “He’ll go hundreds of kilometers, wondering why his solar panel efficiency is going down, before he notices any visibility problems. And the storm is moving west as he moves east. He’ll be too deep in to get out.”
“Are we just watching a tragedy play out?” Cathy asked.
“There’s always hope,” Venkat said. “Maybe he’ll figure it out faster than we think and turn around in time.
Maybe the storm will dissipate unexpectedly.
Maybe he’ll find a way to keep his life support going on less energy than we thought was possible.
Mark Watney is now an expert at surviving on Mars. If anyone can do it, it’s him.”
“Twelve days,” Cathy said to the camera. “All of Earth is watching but powerless to help.”
LOG ENTRY: SOL 462
Another uneventful sol. Tomorrow is an Air Day, so this is kind of my Friday night.
I’m about halfway through Mawrth Vallis now. Just as I’d hoped, the going has been easy. No major elevation changes. Hardly any obstacles. Just smooth sand with rocks smaller than half a meter.
You may be wondering how I navigate. When I went to Pathfinder , I watched Phobos transit the sky to figure out the east-west axis. But Pathfinder was an easy trip compared to this, and I had plenty of landmarks to navigate by.
I can’t get away with that this time. My “map” (such as it is) consists of satellite images far too low-resolution to be of any use.
I can only see major landmarks, like craters 50 kilometers across.
They just never expected me to be out this far.
The only reason I had high-res images of the Pathfinder region is because they were included for landing purposes; in case Martinez had to land way long of our target.
So this time around, I needed a reliable way to fix my position on Mars.
Latitude and longitude. That’s the key. The first is easy. Ancient sailors on Earth figured that one out right away. Earth’s 23.5-degree axis points at Polaris. Mars has a tilt of just over 25 degrees, so it’s pointed at Deneb.
Making a sextant isn’t hard. All you need is a tube to look through, a string, a weight, and something with degree markings. I made mine in under an hour.
So I go out every night with a homemade sextant and sight Deneb. It’s kind of silly if you think about it. I’m in my space suit on Mars and I’m navigating with sixteenth-century tools. But hey, they work.
Longitude is a different matter. On Earth, the earliest way to work out longitude required them to know the exact time, then compare it to the sun’s position in the sky.
The hard part for them back then was inventing a clock that would work on a boat (pendulums don’t work on boats).
All the top scientific minds of the age worked on the problem.
Fortunately, I have accurate clocks. There are four computers in my immediate line of sight right now. And I have Phobos.
Because Phobos is ridiculously close to Mars, it orbits the planet in less than one Martian day. It travels west to east (unlike the sun and Deimos) and sets every eleven hours. And naturally, it moves in a very predictable pattern.
I spend thirteen hours every sol just sitting around while the solar panels charge the batteries. Phobos is guaranteed to set at least once during that time. I note the time when it does. Then I plug it into a nasty formula I worked out and I know my longitude.
So working out longitude requires Phobos to set, and working out latitude requires it to be night so I can sight Deneb.
It’s not a very fast system. But I only need it once a day.
I work out my location when I’m parked, and account for it in the next day’s travel.
It’s kind of a successive approximation thing.
So far, I think it’s been working. But who knows?
I can see it now: me holding a map, scratching my head, trying to figure out how I ended up on Venus.
■■■
Mindy Park zoomed in on the latest satellite photo with practiced ease. Watney’s encampment was visible in the center, the solar cells laid out in a circular pattern as was his habit.
The workshop was inflated. Checking the time stamp on the image, she saw it was from noon local time. She quickly found the status report; Watney always placed it close to the rover when rocks were in abundance, usually to the north.
To save time, Mindy had taught herself Morse code, so she wouldn’t have to look each letter up every morning. She opened an e-mail and addressed it to the ever-growing list of people who wanted Watney’s daily status message.
“ON TRACK FOR SOL 494 ARRIVAL.”
She frowned and added “Note: five sols until dust storm entry.”
LOG ENTRY: SOL 466
Mawrth Vallis was fun while it lasted. I’m in Arabia Terra now.
I just entered the edge of it, if my latitude and longitude calculations are correct. But even without the math, it’s pretty obvious the terrain is changing.
For the last two sols, I’ve spent almost all my time on an incline, working my way up the back wall of Mawrth Vallis.
It was a gentle rise, but a constant one.
I’m at a much higher altitude now. Acidalia Planitia (where the lonely Hab is hanging out) is 3000 meters below elevation zero, and Arabia Terra is 500 meters below.
So I’ve gone up two and a half kilometers.
Want to know what elevation zero means? On Earth, it’s sea level. Obviously, that won’t work on Mars. So lab-coated geeks got together and decided Mars’s elevation zero is wherever the air pressure is 610.5 pascals. That’s about 500 meters up from where I am right now.
Now things get tricky. Back in Acidalia Planitia, if I got off course, I could just point in the right direction based on new data. Later, in Mawrth Vallis, it was impossible to screw up. I just had to follow the canyon.
Now I’m in a rougher neighborhood. The kind of neighborhood where you keep your rover doors locked and never come to a complete stop at intersections. Well, not really, but it’s bad to get off course here.
Arabia Terra has large, brutal craters that I have to drive around.
If I navigate poorly, I’ll end up at the edge of one.
I can’t just drive down one side and up the other.
Rising in elevation costs a ton of energy.
On flat ground, I can make 90 kilometers per day.
On a steep slope, I’d be lucky to get 40 kilometers.
Plus, driving on a slope is dangerous. One mistake and I could roll the rover. I don’t even want to think about that.
Yes, I’ll eventually have to drive down into Schiaparelli. No way around that. I’ll have to be really careful.