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 onto 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 into 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.

“The VAL’s propped open,” Beck’s voice said over the comm. “Starting my traverse across the hull.”

“Copy,” Lewis said.

“This calculation is tricky,” Martinez said. “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 “Okay, the adjustment’s ready to execute.”

“Stand by,” 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” was 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.

• • •

“OKAY, MARTINEZ,” Lewis said, “point us the right direction.”

“Copy,” said Martinez, executing the attitude adjustment.

Johanssen floated into 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.”