“Watney, how you doing?” Lewis's voice said in his ear.
“Fine so far, Commander,” Watney replied. “You mentioned a plan?”
“Affirmative,” she said. “We're going to vent atmosphere to get thrust.”
“How?”
“We're going to blow a hole in the VAL.”
“What!?” Watney said. “How!?”
“Vogel's making a bomb.”
“I knew that guy was a mad scientist!” Watney said. “I think we should just go with my Iron Man idea.”
“That's too risky and you know it,” she replied.
“Thing is,” Watney said, “I'm selfish. I want the memorials back home to be just for me. I don't want the rest of you losers in them. I can't let you guys blow the VAL.”
“Oh,” Lewis said. “Well if you won't let us then- wait... wait a minute... I'm looking at my shoulder patch and it turns out I'm the Commander. Sit tight. We're coming to get you.”
“Smart-ass.”
Being a chemist, Vogel knew how to make a bomb. In fact, much of his training was to avoid making them by mistake.
The ship had few flammables aboard, due to the fatal danger of fire. But food, by its very nature, contained flammable hydrocarbons. Lacking time to sit down and do the math, he estimated.
Sugar has 4000 food-calories per kilogram. One food-calorie is 4184 Joules. Sugar in zero-g will float and the grains will separate, maximizing surface area. In a pure oxygen environment, 16.7 million Joules will be released for every kilogram of sugar used, releasing the explosive force of 8 sticks of dynamite. Such is the nature of combustion in pure oxygen.
Vogel measured the sugar carefully. He poured it into the strongest container he could find, a thick glass beaker. The strength of the container was as important as the explosive. A weak container would simply cause a fireball without much concussive force. A strong container, however, would contain the pressure until it reached trus destructive potential.
He quickly drilled a hole in the stopper, then stripped a section of wire. He ran the wire through the hole.
“Sehr gefährlich,” he mumbled as he poured liquid oxygen from the ship's supply in to the container, then quickly screwed the stopper on. In just a few minutes, he had made a rudimentary pipe bomb.
“Sehr, sehr, gefährlich,”
He floated out of the lab and made his way toward the nose of the ship.
Johanssen worked on the lighting panel as Beck floated toward the airlock.
She grabbed his arm. “Be careful crawling along the hull.”
He turned to face her. “Be careful setting up the bomb.”
She kissed his faceplate then looked away, embarrassed. “That was stupid. Don't tell anyone I did that.”
“Don't tell anyone I liked it,” Beck smiled.
He entered the airlock and sealed the inner door. After depressurizing, he opened the outer door and locked it in place. Grabbing a handrail on the hull, he pulled himself out.
Johanssen watched until he was no longer in view, then returned to the lighting panel. She had deactivated it earlier from her workstation. Pulling a length of the cable out and stripping the ends, she fiddled with a roll of electrical tape until Vogel arrived.
He showed up just a minute later, carefully floating down the hall with the bomb held in both hands.
“I have used a single wire for igniting,” he explained. “I did not want to risk two wires for a spark. It would be dangerous to us if we had static while setting up.”
“How do we set it off?” Johanssen said.
“The wire must reach a high temperature. If you short power through it, that will be sufficient.”
“I'll have to pin the breaker,” Johanssen said, “but it'll work.”
She twisted the lighting wires to the bomb's and taped them off.
“Excuse me,” Vogel said. “I have to return to Airlock 2 to let Dr. Beck back in.”
“Mm,” Johanssen said.
Martinez floated back in to the bridge. “I had a few minutes, so I ran through the aerobrake lockdown checklist for the reactor room. Everything's ready for acceleration and the compartment's sealed off.”
“Good thinking,” Lewis said. “Prep the attitude correction.”
“Roger, Commander.” Martinez said, drifting to his station. “It'll take me a sec... I need to do everything backward. The VAL's in front, so the source of thrust will be exactly opposite to our engines. Our software wasn't expecting us to have an engine there. I just need to tell it we plan to thrust toward Mark.”
“Take your time and get it right,” Lewis said. “And don't execute till I give you the word. We're not spinning the ship around while Beck's out on the hull.”
“Roger.” He said. After a moment, he added “Ok, the adjustment's ready to execute.”
“Standby.” Lewis said.
Vogel, back in his suit, depressurized Airlock 2 and opened the outer door.
“Bout time,” Beck said, climbing in.
“Sorry for the delay,” Vogel said. “I was required to make a bomb.”
“This has been kind of a weird day,” Beck said. “Commander, Vogel and I are in position.”
“Copy,” came Lewis's response. “Get up against the fore wall of the airlock. It's going to be about one g for four seconds. Make sure you're both tethered in.”
“Copy,” Beck said as he attached his tether. The two men pressed themselves against the wall.
“Ok, Martinez,” Lewis said, “Point us the right direction.”
“Copy,” said Martinez, executing the attitude adjustment.
Johanssen floated in to the bridge as the adjustment was performed. The room rotated around her as she reached for a handhold. “The bomb's ready, and the breaker's jammed closed,” she said. “I can set it off by remotely turning on Lighting Panel 41.”
“Seal the bridge and get to your station,” Lewis said.
“Copy,” Johanssen said. Unstowing the emergency seal, she plugged the entrance to the bridge. With a few turns of the crank, the job was done. She returned to her station and ran a quick test. “Increasing Bridge pressure to 1.03 atmospheres... pressure is steady we have a good seal.”
“Copy,” Lewis said. “Time to intercept?”
“28 seconds,” Johanssen said.
“Wow,” Martinez said. “We cut that pretty close.”
“You ready, Johanssen?” Lewis asked.
“Yes,” Johanssen said. “All I have to do is hit enter.”
“Martinez, how's our angle?”
“Dead-on, Commander,” Martinez reported.
“Strap in,” Lewis said.
The three of them tightened the restraints of their chairs.
“20 seconds,” Johanssen said.
Teddy took his seat in the VIP room. “What's the status?” He asked.
“15 seconds till they blow the VAL,” Venkat said. “Where have you been?”
“On the phone with the President,” Teddy said. “Do you think this will work?”
“I have no idea,” Venkat said. “I've never felt this helpless in my life.”
“If it's any consolation,” Teddy said, “Pretty much everyone in the world feels the same way.”
On the other side of the glass, Mitch paced to and fro.
“5... 4... 3...” Johanssen said.
“Brace for acceleration,” Lewis said.
“2... 1...” Johanssen continued. “Activating Panel 41.”
She pressed enter.
Inside Vogel's bomb, the full current of the ship's internal lighting system flowed through a thin, exposed wire. It quickly reached the ignition temperature of the sugar. What would have been a minor fizzle in Earth's atmosphere became an uncontrolled conflagration in the container's pure oxygen environment. In under 100 milliseconds, the massive combustion pressure burst the container and the resulting explosion ripped the airlock door to shreds.
The internal air of Hermes rushed through the open VAL, blasting Hermes in the other direction.
Vogel and Beck were pressed against the wall of Airlock 2. Lewis, Martinez, and Johanssen endured the acceleration in their seats. It was not a dangerous amount of force, in fact it was less than the force of Earth's surface gravity. But it was inconsistent and jerky.
After four seconds, the shaking died down and the ship returned to weightlessness.
“Reactor room still pressurized,” Martinez reported.
“Bridge seal holding,” Johanssen said. “Obviously.”
“Damage?” Martinez said.
“Not sure yet,” Johanssen said. “I have External Camera four pointed along the nose. I don't see any problems with the hull near the VAL.”
“Worry about that later,” Lewis said. “What's our relative velocity and distance to MAV?”
Johanssen typed quickly. “We'll get within 22 meters and we're at 12 meters per second. We actually got better than expected thrust.”
“Watney,” Lewis said. “It worked. Beck's on his way.”
“Score!” Watney responded.
“Beck,” Lewis said. “You're up. 12 meters per second.”
“Close enough!” Beck replied.
“I'm going to jump out,” Beck said. “Should get me another two or three meters per second.”
“Understood,” Vogel said, loosely gripping Beck's tether. “Good luck, Dr. Beck.”
Placing his feet on the back wall, Beck coiled and leaped out of the airlock.
Once free, he got his bearings. A quick look to his right showed him what he could not see from inside the airlock.
“I have visual!” he said. “I can see MAV! Jesus, Mark, what did you do to that thing?”
“You should see what I did to the rover,” Watney radioed back.
Beck thrusted on an intercept course. He had practiced this many times. The presumption in those practice sessions was that he'd be rescuing a crewmate whose tether had broken, but the principle was the same.
“Johanssen,” he said, “You got me on radar?”
“Affirmative,” she replied.
“Call out my relative velocity to Mark every 2 seconds or so.”
“Copy. 5.2 meters per second.”
“Hey Beck,” Watney said. “The front's wide open. I'll get up there and be ready to grab at you.”
“Negative,” interrupted Lewis. “No untethered movement. Stay strapped to your chair until you're latched to Beck.”
“Copy,” Watney said.
“3.1 meters per second,” Johanssen reported.
“Going to coast for a bit,” Beck said. “Gotta catch up before I slow it down.” He rotated himself in preparation for the next burn.
“11 meters to target,” Johanssen said.
“Copy.”
“6 meters,” Johanssen said.
“Aaaaand, counter-thrusting.” Beck said, firing the MMU thrusters again. The MAV loomed before him. “Velocity?” He asked.
“1.1 meters per second,” Johanssen said.
“Good enough,” he said, reaching for the ship. “I'm drifting toward it. I think I can get my hand on some of the torn canvas...”
The tattered canvas beckoned as the only handhold on the otherwise smooth ship. Beck reached, extending as best he could, and managed to grab hold.
“Contact,” Beck said. Firming his grip, he pulled his body forward and lashed out with his other hand to grab more canvas. “Firm contact!”
“Dr. Beck,” Vogel said. “We have past closest approach point and you are now getting further away. You have 169 meters of tether left. Enough for 14 seconds.”
“Copy,” Beck said.
Pulling his head to the opening, he looked inside the compartment to see Watney strapped to his chair.
“Visual on Watney!” He reported.
“Visual on Beck!” Watney reported.
“How ya doin', man?” Beck said, pulling himself in to the ship.
“I... I just...” Watney said. “Give me a minute. You're the first person I've seen in 18 months.”
“We don't have a minute,” Beck said, kicking off the wall. “We've got 11 seconds before we run out of tether.”
Beck's course took him to the chair where he clumsily collided with Watney. The two gripped each others' arms to keep Beck from bouncing away. “Contact with Watney!” Beck said.
“8 seconds, Dr. Beck,” Vogel radioed.
“Copy,” Beck said as he hastily latched the front of his suit to the front of Watney's with tether clips. “Connected,” he said.
Watney released the straps on his chair. “Restraints off.”
“We're outa' here,” Beck said, kicking off the chair toward the opening.
The two men floated across the MAV cabin to the opening. Beck reached out his arm and pushed off the edge as they passed through.
“We're out,” Beck reported.
“5 seconds,” Vogel said.
“Relative velocity to Hermes: 12 meters per second,” Johanssen said.
“Thrusting,” Beck said, activating his MMU.
The two accelerated toward Hermes for a few seconds. Then the MMU controls on Beck's heads-up display turned red.
“That's it for the fuel,” Beck said. “Velocity?”
“5 meters per second,” Johanssen replied.
“Standby,” Vogel said. Throughout the process, he had been feeding tether out of the airlock. Now he gripped the ever-shrinking remainder of the rope with both hands. He didn't clamp down on it; that would pull him out of the airlock. He simply closed his hands over the tether to create friction.
Hermes pulled Beck and Watney along, with Vogel's use of the tether acting as a shock absorber. If Vogel used too much force the shock of it would pull the tether free from Beck's suit clips. If he used too little the tether would run out before they matched speeds, then it would have a hard stop at the end, which would also rip it out of Beck's suit clips.
Vogel managed to find the balance. After a few seconds of tense, gut-feel physics, Vogel felt the force on the tether abate.
“Velocity 0!” Johanssen reported excitedly.
“Reel 'em in, Vogel,” Lewis said.
“Copy,” Vogel said. Hand over hand, he slowly pulled his crewmates toward the airlock. After a few seconds, he stopped actively pulling and simply took in the line as they coasted toward him.
They floated in to the airlock, and Vogel grabbed them. Beck and Watney both reached for handholds on the wall as Vogel worked his way around them and closed the outer door.
“Aboard!” Beck said.
“Airlock 2 outer door closed,” Vogel said.
“Yes!” Martinez yelled.
“Copy,” Lewis said.
Lewis's voice echoed across the world: “Houston, this is Hermes Actual. Six crew safely aboard.”
The control room exploded with applause. Leaping from their seats, they cheered, hugged, and cried. The same scene played out all over the world in parks, bars, civic centers, living rooms, classrooms, and offices.
Mitch haggardly pulled off his headset and turned to face the VIP room. Through the glass, he saw various well-suited men and women cheering wildly. He looked at Venkat and let out a heavy sigh of relief.
Venkat put his head in his hands and whispered “Thank the gods.”
Teddy pulled a blue folder from his briefcase and stood. “Annie will be wanting me in the press room.”
“Guess you don't need the red folder today,” Venkat said.
“Honestly, I didn't make one.” As he walked out he added “Good work, Venk. Now get them home.”
LOG ENTRY: MISSION DAY 687
That “687” caught me off guard for a minute. On Hermes, we track time by mission days. It may be Sol 549 down on Mars, but it's Mission Day 687 up here. And you know what? It doesn't matter what time it is on Mars cause I'M NOT FUCKING THERE!
Oh my god. I'm really not on Mars anymore. I can tell because there's no gravity and there are other humans around. I'm still adjusting.
If this were a movie, everyone would have been in the airlock and there would have been high-fives all around. But it didn't pan out that way.
I broke two ribs during the MAV ascent. They were sore the whole time, but they really started screaming when Vogel pulled us in to the airlock by the tether. I didn't want to distract the people who were saving my life so I muted off my mic and screamed like a little girl.
It's true, you know. In space, no one can hear you scream like a little girl.
Once they got me in to Airlock 2, they opened the inner door and I was finally aboard again. Hermes was still in vacuo, so we didn't have to cycle the airlock.
Beck told me to go limp and pushed me down the corridor toward his quarters (which serve as the ship's “sick bay” when needed).