The rover crested a nearby dune with the trailer in tow. It slowed for a few moments, then continued toward the ship at top speed. It came to a stop twenty meters away.
There it remained for ten minutes while the astronaut inside suited up.
He stumbled excitedly out of the airlock, falling to the ground then scrambling to his feet. Beholding the MAV, he gestured to it with both arms, as if in disbelief.
He leaped into the air several times, arms held high with fists clenched. Then he knelt on one knee and fist-pumped repeatedly.
Running to the spacecraft, he hugged Landing Strut B. After a few moments, he broke off the embrace to perform another round of leaping celebrations.
Now fatigued, the astronaut stood with arms akimbo, looking up at the sleek lines of the engineering marvel before him.
Climbing the ladder on the landing stage, he reached the ascent stage and entered the airlock. He sealed the door behind him.
CHAPTER 25
I finally made it! I’m at the MAV!
Well, right this second, I’m back in the rover. I did go into the MAV to do a systems check and boot-up. I had to keep my EVA suit on the whole time because there’s no life support in there just yet.
It’s going through a self-check right now, and I’m feeding it oxygen and nitrogen with hoses from the rover. This is all part of the MAV’s design. It doesn’t bring air along. Why would it? That’s a needless weight when you’ll have a Hab full of air right next door.
I’m guessing folks at NASA are popping champagne right now and sending me lots of messages. I’ll read them in a bit. First things first: Get the MAV some life support. Then I’ll be able to work inside comfortably.
And then I’ll have a boring conversation with NASA. Well, the content may be interesting, but the fourteen-minute transmission time between here and Earth will be a bit dull.
[13:07] HOUSTON: Congratulations from all of us here at Mission Control! Well done! What’s your status?
[13:21] MAV: Thanks! No health or physical problems. The rover and trailer are getting pretty worn out, but still functional. Oxygenator and regulator both working fine. I didn’t bring the water reclaimer. Just brought the water. Plenty of potatoes left. I’m good to last till 549.
[13:36] HOUSTON: Glad to hear it. Hermes is still on track for a Sol 549 flyby. As you know, the MAV will need to lose some weight to make the intercept. We’re going to get you those procedures within the day. How much water do you have? What did you do with urine?
[13:50] MAV: I have 550 liters of remaining water. I’ve been dumping urine outside along the way.
[14:05] HOUSTON: Preserve all water. Don’t do any more urine dumps. Store it somewhere. Turn the rover’s radio on and leave it on. We can contact it through the MAV.
BRUCE TRUDGED into Venkat’s office and unceremoniously plopped down in a chair. He dropped his briefcase and let his arms hang limp.
“Have a good flight?” Venkat asked.
“I only have a passing memory of what sleep is,” Bruce said.
“So is it ready?” Venkat asked.
“Yes, it’s ready. But you’re not going to like it.”
“Go on.”
Bruce steeled himself and stood, picking up his briefcase. He pulled a booklet from it. “Bear in mind, this is the end result of thousands of hours of work, testing, and lateral thinking by all the best guys at JPL.”
“I’m sure it was hard to trim down a ship that’s already designed to be as light as possible,” Venkat said.
Bruce slid the booklet across the desk to Venkat. “The problem is the intercept velocity. The MAV is designed to get to low Mars orbit, which only requires 4.1 kps. But the Hermes flyby will be at 5.8 kps.”
Venkat flipped through the pages. “Care to summarize?”
“First, we’re going to add fuel. The MAV makes its own fuel from the Martian atmosphere, but it’s limited by how much hydrogen it has. It brought enough to make 19,397 kilograms of fuel, as it was designed to do. If we can give it more hydrogen, it can make more.”
“How much more?”
“For every kilogram of hydrogen, it can make thirteen kilograms of fuel. Watney has five hundred and fifty liters of water. We’ll have him electrolyze it to get sixty kilograms of hydrogen.” Bruce reached over the desk and flipped a few pages, pointing to a diagram. “The fuel plant can make seven hundred and eighty kilograms of fuel from that.”
“If he electrolyzes his water, what’ll he drink?”
“He only needs fifty liters for the time he has left. And a human body only borrows water. We’ll have him electrolyze his urine, too. We need all the hydrogen we can get our hands on.”
“I see. And what does seven hundred and eighty kilograms of fuel buy us?” Venkat asked.
“It buys us 300 kilograms of payload. It’s all about fuel versus payload. The MAV’s launch weight is over 12,600 kilograms. Even with the bonus fuel, we’ll need to get that down to 7,300 kilograms. So the rest of this booklet is how to remove over 5,000 kilograms from the ship.”
Venkat leaned back. “Walk me through it.”
Bruce pulled another copy of the booklet from his briefcase. “There were some gimmes right off the bat. The design presumes five hundred kilograms of Martian soil and rock samples. Obviously we won’t do that. Also, there’s just one passenger instead of six. That saves five hundred kilograms when you consider their weight plus their suits and gear. And we can lose the other five acceleration chairs. And of course, we’ll remove all nonessential gear—the med kit, tool kit, internal harnessing, straps, and anything else that isn’t nailed down. And some stuff that is.
“Next up,” he continued, “We’re ditching all life support. The tanks, pumps, heaters, air lines, CO2 absorption system, even the insulation on the inner side of the hull. We don’t need it. We’ll have Watney wear his EVA suit for the whole trip.”
“Won’t that make it awkward for him to use the controls?” Venkat asked.
“He won’t be using them,” Bruce said. “Major Martinez will pilot the MAV remotely from Hermes. It’s already designed for remote piloting. It was remotely landed, after all.”
“What if something goes wrong?” Venkat asked.
“Martinez is the best trained pilot,” Bruce said. “If there is an emergency, he’s the guy you want controlling the ship.”
“Hmm,” Venkat said cautiously. “We’ve never had a manned ship controlled remotely before. But okay, go on.”
“Since Watney won’t be flying the ship,” Bruce continued, “he won’t need the controls. We’ll ditch the control panels and all the power and data lines that lead to them.”
“Wow,” Venkat said. “We’re really gutting this thing.”
“I’m just getting started,” Bruce said. “The power needs will be dramatically reduced now that life support is gone, so we’ll dump three of the five batteries and the auxiliary power system. The orbital maneuvering system has three redundant thrusters. We’ll get rid of those. Also, the secondary and tertiary comm systems can go.”
“Wait, what?” Venkat said, shocked. “You’re going to have a remote-controlled ascent with no backup comm systems?”
“No point,” Bruce said. “If the comm system goes out during ascent, the time it takes to reacquire will be too long to do any good. The backups don’t help us.”
“This is getting really risky, Bruce.”
Bruce sighed. “I know. There’s just no other way. And I’m not even to the nasty stuff yet.”