Griggs wasn’t there, but she saw his Thinkpad, drifting at the end of its data cord. The screen flashed a bright red

“Decompression” warning.

The air pressure was down to six hundred fifty and dropping. They had only minutes to work, minutes before their brains would not function.

He must have gone in search of the leak, she thought. He’s going to close off the damaged module.

She dove into the U.S. Lab, through that thickening white mist.

Was it mist or was it her vision fogging over from hypoxia? A warning that unconsciousness was closing in? She shot through the darkness and felt disoriented by the warning lights continuing to flash like a strobe. She banged into the far hatchway. Her coordination was off, and her clumsiness getting worse. She through the hatch opening, into Node 2.

Griggs was there. He was struggling to disconnect a tangle of cables strung between the NASDA and European modules.

“The leak’s in NASDA!” he yelled over the screaming sirens. “If we can clear the cables from this hatchway and close it off, we isolate the module.” She dove forward to help him yank the cables apart. Then she found one that could not be disconnected. “What the hell’s this? she said. All cables leading through hatchways were supposed to be easy to pull apart in case of an emergency. This one was continuous—a violation of safety rules. “It doesn’t have a quick release!” she yelled.

“Get me a knife and I’ll cut it!” She spun around, dove back into the U.S. Lab. A knife. Where the hell is a knife? Through the red flashes of light, she saw medical locker. A scalpel. She yanked open the drawer, reached into the instrument tray, and went flying back into Node 2.

Griggs took the scalpel and began to sever the cable.

“What can we do to help?” came Luther’s shout.

Emma turned and saw him, along with Nicolai and Diana, hovering anxiously in the hatchway.

“The breach is in NASDA! -” she said. “We’re gonna close off the module!” Sparks suddenly shot out like fireworks. Griggs yelped and jerked away from the cable. “Shit! It’s a live wire!”

“We’ve got to cut it!” said Emma.

“And get fried to a crisp? I don’t think so.”

“Then how do we seal the hatch?” Luther said, “Pull back! Pull back into the lab! We’ll close off the whole node. Isolate this end of the station.” Griggs looked at the sparking wire. He didn’t want to close off Node 2, because it meant sacrificing both the NASDA and European modules, which would be completely depressurized and unreachable. And it meant sacrificing the shuttle docking port, which also led off Node 2.

“Pressure’s dropping, folks!” called Diana, reading a handheld pressure gauge. “We’re down to six hundred twenty-five millimeters! Just pull the fuck back, and let’s close off the node!” Emma could already feel herself breathing faster, trying to catch her breath. Hypoxia. They were all going to black out if she didn’t do something soon.

She tugged Griggs’s arm. “Pull back! It’s the only way to save the station!” He gave a stunned nod and retreated with Emma into the U.S. Lab.

Luther tried to tug the hatch shut, but he couldn’t get it to budge. Now that they were outside Node 2, they had to pull, not push the hatch shut. And they were working against the rush of escaping air, in a rapidly depressurizing atmosphere.

“We’ll have to abandon this module too!” yelled Luther. “Retreat to Node 1 and close off the next hatch!”

“Hell no!” Griggs said. “I’m not giving up this module as well!”

“Griggs, we’ve got no choice. I can’t pull this hatch shut!”

“Then let me do it!” Griggs grabbed the handle and strained to pull it shut, but the hatch moved only a few inches before he had to let go in exhaustion.

“You’re gonna kill us all just to save this fucking module!” shouted Luther.

It was Nicolai who suddenly yelled out the solution. “Mir! Feed the leak! Feed the leak!” He shot out of the lab, headed toward the Russian end of the station.

Mir. Every one immediately knew what he was talking about. 1997. The collision with Mir’s Spektra module. There had been a breach in the hull, and Mir had begun to leak its precious air into space. The Russians, with years more experience in manned space stations, were ready with their emergency response, feeding the leak. Pour extra oxygen into the module to raise the pressure.

Not only would it buy them time to work, it might narrow the pressure gradient enough so they could pull the hatch shut.

Nicolai came flying back into the lab with two oxygen tanks.

Frantically he opened the valves all the way. Even over the screaming sirens, they could hear the screech of air escaping from tanks. Nicolai tossed both tanks into Node 2. Feeding the leak. They were building air pressure on the other side of the hatch.

They were also pouring oxygen into a module with a live wire, thought Emma, remembering the sparks. It could trigger an explosion.

“Now!” Nicolai shouted. “Try to close the hatch!” Luther and Griggs both grabbed the handle and pulled. They would never know if it was due to their combined desperation or if the oxygen tanks had succeeded in dropping the pressure gradient across that hatchway, but the hatch slowly began to swing shut.

Griggs locked it in place.

For a moment he and Luther simply hung limp in midair, both of them too exhausted to say a word. Then Griggs turned, his face bright with sweat in the flashing lights.

“Now let’s shut off that fucking racket,” he said.

The Thinkpad was still floating where he’d left it in Node 1. Peering at the glowing screen, he rapidly tapped in a series of commands. To everyone’s relief, the sirens stopped screaming. flashing red lights also stopped, leaving only a constant yellow glow on the caution-and-warning panels. At last they could communicate without shouting.

“Air pressure is back up to six hundred ninety and rising,” he said, and gave a laugh of relief. “Looks like we’re home free.”

“Why are we still at Class 3 caution?” asked Emma, pointing to the yellow light on the screen. A Class 3 caution meant one of three possibilities. Their backup guidance computer was down, one of their control motion gyros was inoperative, or they’d lost their S-band radio link to Mission Control.

Griggs tapped a few more keys. “It’s the S-band. We’ve lost it. Discovery must have hit our P-1 truss and taken out the radio. Looks like they also hit our port solar arrays. We’ve lost a photovoltaic module. That’s why we’re still in power down.”

“Houston must be going bonkers, wondering what’s happening,” said Emma.

“And now they can’t reach us. What about Discovery? What’s happened to them?” Diana, already working the space-to-space radio, said, “Discovery isn’t responding. They may be out of UHF range.” Or they were all dead and couldn’t respond.

“Can we get these lights back?” said Luther. “Cross-strap primary power?” Griggs began to tap on the keyboard again. Part of the beauty of ISS’s design lay in its redundancy. Each of its power channels were configured to supply electricity for specific loads, but channels could be rerouted—”cross-strapped”—as needed.

Though they’d lost one photovoltaic module, they had three others to tap into.

Griggs said, “I know this is a cliche, but let there be light.” He hit a computer key, and the module lights barely brightened. But was enough to navigate through hatchways. “I’ve rerouted power. Nonessential payload functions are now off the grid.” He released a deep breath and looked at Nicolai. “We need to contact Houston. It’s your show, Nicolai.”

The Russian understood at once what he had to do. Moscow’s Mission Control maintained its own separate communications link with the station. The collision should not have affected the end of ISS. Nicolai gave a terse nod. “Let us hope Moscow has paid its electric bill.”