Page 43 of The Martian

“And we don't need a precision landing. Watney can travel hundreds of kilometers if necessary. We just need to land close enough for him to reach it. This ends up being a standard tumble-land presupply. All we have to do is make it quickly. So let's get to it.”

[08:02]JPL: We've spun up a project to get you food. It's been in progress for a week or so. We can get it to you before you starve, but it'll be tight. It'll just be food and a radio. We can't send an Oxygenator, Water Reclaimer, or any of that other stuff without powered descent.

[08:16]WATNEY: No complaints here! You get me the food, I'll be a happy camper. I've got all Hab systems up and running again. The Water Reclaimer is working fine now that I replaced the burst hoses. As for water supply, I have 620L remaining. I started with 900L (300 to start with, 600 more from reducing hydrazine). So I lost almost 300L to sublimation. Still, with the Water Reclaimer operational again, it's plenty.

[08:31]JPL: Good, keep us posted on any mechanical or electronic problems. By the way, the name of the probe we're sending is “Iris”. Named after the Greek goddess who traveled the heavens with the speed of wind. She's also the goddess of rainbows.

[08:47]WATNEY: Gay probe coming to save me. Got it.

Rich Purnell sipped coffee in the silent building. Only his cubicle illuminated the otherwise dark room. Continuing with his computations, he ran a final test on the software he'd written. It passed.

With a relieved sigh, he sank back in his chair. Checking the clock on his computer, he shook his head. 3:42am.

Being an astrodynamicist, Rich rarely had to work late. His job was to find the exact orbits and course corrections needed for any given mission. Usually, it was one of the first parts of a project; all the other steps being based on the orbit.

But this time, things were reversed. Iris needed an orbital path, and nobody knew when it would launch. A non-Hoffman Mars-transfer isn't challenging, but it does require the exact locations of Earth and Mars.

Planets move as time goes by. A course calculated for a specific launch date will work only for that date. Even a single day's difference would result in missing Mars entirely.

So Rich had to calculate many courses. He had a range of 25 days during which Iris might launch. He calculated one course for each.

He began an email to his boss.

Mike, he typed, Attached are the courses for Iris, in 1-day increments. We should start peer-review and vetting so they can be officially accepted. And you were right, I was here almost all night.

It wasn't that bad. Nowhere near the pain of calculating orbits for Hermes. I know you get bored when I go in to the math, so I'll summarize: The small, constant thrust of Hermes's ion drives is much harder to deal with than the large point-thrusts of presupply probes.

All 25 of the courses take 414 days, and vary only slightly in thrust duration and angle.  The fuel requirement is nearly identical for the orbits and is well within the capacity of EagleEye's booster.

It's too bad. Earth and Mars are really badly positioned. Heck, it's almost easier to-

He stopped typing.

Furrowing his brow, he stared in to the distance.

“Hmm.” he said.

Grabbing his coffee cup, he went to the break room for a refill.

“I know you're all busy,” Teddy said, “so let's make this fast. I need status on Project Iris from all departments. Venkat, let's start with you.”

“The mission team's ready,” Venkat said. “There was a minor turf war between the Ares-3 and Ares-4 presupply control teams. The Ares-3 guys said they should run it, cause while Watney's on Mars, Ares-3 is still in progress. The Ares-4 team points out it's their co-opted probe in the first place. I ended up going with Ares-3.”

“Did that upset Ares-4?” Teddy asked.

“Yeah, but they'll get over it. They have 13 presupply missions coming up. They won't have time to be pissy.”

“Mitch,” Teddy said to the flight controller, “What about the launch?”

“We've got a control room ready,” Mitch replied. “I'll oversee the launch, then hand cruise and landing over to Venkat's guys.”

“Media?” Teddy said, turning to Annie Montrose.

“I'm giving daily updates to the press,” she said. “Everyone knows Watney's fucked if this doesn't work. The public hasn't been this engaged in ship construction since Apollo 11. CNN's 'The Watney Report' has been the #1 show in its time-slot for the past two weeks.”

“The attention is good,” Teddy said. “It'll help get us emergency funding from Congress. Maurice, how's the booster?”

“It's all right for now,” said Maurice Stein, Director of Pad Operations. “But it's not ideal. EagleEye 3 was set to launch. Boosters aren't designed to stand upright and bear the stress of gravity for long periods. We're adding external supports that we'll remove before launch. It's easier than disassembly. Also the fuel is corrosive to the internal tanks, so we had to drain it. In the mean time, we're performing inspections on all systems every three days.”

“Good, good,” Teddy nodded. “Now for the big question: Bruce? How's Iris coming along?”

“We're behind,” Bruce said with a tired shake of his head. “We're going as fast as we can, but it's just not fast enough.”

“I can find money for overtime,” Teddy offered.

“We're already working around the clock.”

“How far behind are we walking about?” Teddy asked.

“We've been at it 29 days; so we only have 19 left,” Bruce explained. “After that, the Pad  needs 13 days to mount it on the booster. We're at least two weeks behind.”

“Is that as far behind as you're going to get?” Teddy asked. “Or will you slip more?”

Bruce shrugged. “If we don't have any more problems, it'll be two weeks late. But we always have problems.”

“Give me a number,” Teddy said.

“15 days,” Bruce responded. “If I had another 15 days, I'm sure we could get it done in time.”

“All right,” Teddy said. “Let's create 15 days.”

Turning his attention to the Ares-3 Flight Surgeon, Teddy asked “Dr. Keller, can we reduce Watney's food intake to make the rations last longer?”

“Sorry, but no,” Keller said. “he's already at a minimal calorie count. In fact, considering the amount of physical labor he does, he's eating far less than he should. And it's only going to get worse. Soon his entire diet will be potatoes and vitamin supplements. He's been saving protein-rich rations for later use, but he'll still be malnourished.”