“Aye, Commander,” Martinez said, softening his scowl.

“Resetting the sim,” Johanssen said. “Anything specific you want to try?”

“Surprise me,” Martinez said.

Lewis left the control room and made her way to the reactor. As she climbed “up” the ladder to the center of the ship, the centripetal force on her diminished to zero. Vogel looked up from a computer console. “Commander?”

“How are the engines?” she asked, grabbing a wall-mounted handle to stay attached to the slowly turning room.

“All working within tolerance,” Vogel said. “I am now doing a diagnostic on the reactor. I am thinking that Johanssen is busy with the launching training. So perhaps I do this diagnostic for her.”

“Good idea,” Lewis said. “And how’s our course?”

“All is well,” Vogel said. “No adjustments necessary. We are still on track to planned trajectory within four meters.”

“Keep me posted if anything changes.”

“Ja, Commander.”

Floating to the other side of the core, Lewis took the other ladder out, again gaining gravity as she went “down.” She made her way to the Airlock 2 ready room.

Beck held a coil of metal wire in one hand and a pair of work gloves in the other. “Heya, Commander. What’s up?”

“I’d like to know your plan for recovering Mark.”

“Easy enough if the intercept is good,” Beck said. “I just finished attaching all the tethers we have into one long line. It’s two hundred and fourteen meters long. I’ll have the MMU pack on, so moving around will be easy. I can get going up to around ten meters per second safely. Any more, and I risk breaking the tether if I can’t stop in time.”

“Once you get to Mark, how fast a relative velocity can you handle?”

“I can grab the MAV easily at five meters per second. Ten meters per second is kind of like jumping onto a moving train. Anything more than that and I might miss.”

“So, including the MMU safe speed, we need to get the ship within twenty meters per second of his velocity.”

“And the intercept has to be within two hundred and fourteen meters,” Beck said. “Pretty narrow margin of error.”

“We’ve got a lot of leeway,” Lewis said. “The launch will be fifty-two minutes before the intercept, and it takes twelve minutes. As soon as Mark’s S2 engine cuts out, we’ll know our intercept point and velocity. If we don’t like it, we’ll have forty minutes to correct. Our engine’s two millimeters per second may not seem like much, but in forty minutes it can move us up to 5.7 kilometers.”

“Good,” Beck said. “And two hundred and fourteen meters isn’t a hard limit, per se.”

“Yes it is,” Lewis said.

“Nah,” Beck said. “I know I’m not supposed to go untethered, but without my leash I could get way out there—”

“Not an option.” Lewis said.

“But we could double or even triple our safe intercept range—”

“We’re done talking about this,” Lewis said sharply.

“Aye, Commander.”