Page 60 of Project Hail Mary

Stratt shook her head. “No. That won’t fly. We have to keep things simple. As simple as possible. Big, solid ship, minimal moving parts. The more complications we have the more points of failure we risk.”

“It’s worth the risk,” said Lokken.

“We’d have to add a huge counterweight to theHail Maryto even make that work.” Stratt pursed her lips. “I’m sorry, but we barely have enough energy to make the Astrophage for the current mass limit. We can’t just double it.”

“Wait. We have enough energy to make all the fuel? When did that happen—?” I said.

“You don’t need to add mass,” Lokken said. She pulled another paper from her purse and slapped it down on the table. “If you take the current design, cut it in half between the crew compartment and the fuel tanks, the two sides will have a good mass ratio for a centrifuge.”

Stratt peered at the diagram. “You put all the fuel on the same side. That’s two million kilograms.”

“No.” I shook my head. “The fuel would be gone.”

They both looked at me.

“It’s a suicide mission,” I said. “The fuel will be gone when they get to Tau Ceti. Lokken picked a split point where the back of the ship will weigh three times as much as the front. It’s a good mass ratio for a centrifuge. It could work.”

“Thank you,” said Lokken.

“How do you cut a ship in half?” asked Stratt. “How does it become a centrifuge?”

Lokken flipped the diagram over to reveal a detailed image showing a faring between the two ship halves. “Spools of Zylon cabling between the crew compartment and the rest of the ship. We could simulate one g of gravity with a hundred meters of separation.”

Stratt pinched her chin. Had someone actually changed her mind on something?

“I don’t like complexity…” she said. “I don’t like risk.”

“Thisremovescomplexity and risk,” Lokken said. “The ship, the crew, the Astrophage…it’s all just a support system for the lab equipment. Youneedreliable equipment. Stuff that’s been in use for years with millions of man-hours of commercial use. Every imaginable kink has been worked out of those systems. If you have one g of gravity—to make sure they’ll be in the environment they were perfected for—you get the benefit of all that reliability.”

“Hmm,” said Stratt. “Grace? Your thoughts?”

“I…I think it’s a good idea.”

“Really?”

“Yeah,” I said. “I mean, we already have to design the ship to withstand four years of constant acceleration at one and a half g’s or so. It’s going to be pretty solid.”

She took a longer look at Lokken’s diagram. “Wouldn’t this make the artificial gravity in the crew area upside down?”

And she was right. TheHail Marywas designed so that “down” was “toward the engines.” As the ship accelerates, the crew is pushed “down” to the floor. But inside a centrifuge, “down” is always “away from the center of rotation.” So the crew would all be pushed toward the nose of the ship.

“Yes, that would be a problem.” Lokken pointed to the diagram. The cables didn’t attach directly to the crew compartment. They attached to two large discs on either side. “The cabling attaches to these big hinges. The whole front half of the ship can rotate 180 degrees. So when they’re in centrifuge mode, the nose will face inward toward the other half of the ship. Inside the crew compartment, the force of gravity will be away from the nose—same as when the engines are thrusting.”

Stratt took it in. “This is a fairly complicated piece of machinery and you’ll be breaking the ship into two parts. You honestly think this is less of a risk?”

“Less risk than using brand-new, insufficiently tested equipment. Trust me, I’ve used sensitive equipment most of my career,” I said. “It’s finicky and delicate even in ideal conditions.”

Stratt picked up her pen and tapped it on the table several times. “Okay. We’ll do it.”

Lokken smiled. “Excellent. I’ll write up a paper and send it along to the UN. We can form a committee—”

“No, I said we’ll do it.” Stratt stood up. “You’re with us now, Dr.Lokken. Pack a bag and meet us at Genève Aéroport. Terminal 3, private plane calledStratt.”

“What? I work for ESA. I can’t just—”

“Yeah, don’t bother,” I said. “She’s going to call your boss or your boss’s boss or whatever and have you assigned to her. You just got drafted.”

“I…I wasn’t volunteering todesignit personally,” Lokken protested. “I only meant to point out—”