The damage assessment took four minutes.

Commander Tom Callahan stood in the zero-gravity harness of the Prometheus cockpit, his eyes moving across the diagnostic displays with the mechanical precision of a man who had spent fifteen years in the Air Force and three months in orbit. The numbers were bad. Not catastrophic—bad. The port engine was gone, torn away by a swarm of micrometeoroids that had hit at seventeen kilometers per second. The fuel line to the auxiliary thruster was ruptured. The thermal shielding on the starboard side was compromised.

He could fix some of it. Not all.

"Talk to me, Tom," Dr. Sarah Mitchell said from the co-pilot's seat. She was thirty years old, an astrophysicist from Caltech, with sharp eyes and a habit of biting her lower lip when she was thinking. She had been quiet for the last ten minutes, which was unusual. Sarah was not a quiet person.

"One port engine gone. Fuel line ruptured on auxiliary. Thermal shielding damaged on starboard. We can maneuver, but not for long. Maybe three weeks of correction burns before we run out of delta-v."

Mars was a red dot through the viewport, small and indifferent. They were three months from orbit insertion. Three months of life support, of food rations, of sleeping in harnesses and eating from tubes and talking to each other in the flat, toneless voices of people who had been alone together for ninety days.

"Can you fix it?" Sarah asked.

Tom looked at the damage report. The port engine would need a complete replacement. They had no spare. The fuel line could be jury-rigged with materials from the maintenance bay, but it would require an EVA—three hours outside the ship in the cold dark, working with gloved hands on a pipe that was leaking cryogenic fuel.

"I can try," he said.

"Three hours," Sarah said. "In the dark."

"Three hours."

He did not tell her about the second problem. He had seen it in the data, in a line item buried in the structural integrity report that nobody would look at unless they were looking for it. The micrometeoroid swarm had not just torn through the engine. It had punctured the primary oxygen recycler. The recycler was still functioning—at sixty percent capacity—but it was bleeding oxygen slowly, imperceptibly, and in three months the tank would be empty.

In three months, they would both suffocate.

Unless someone made a choice.

Tom went outside at 0600 ship time. The EVA suit was heavy and awkward, even in zero-g. He could see Earth through the viewport behind him—a blue-white dot, smaller than he expected, smaller than any map had prepared him for. He thought about Eleanor, his ex-wife, who had told him two years ago that she did not hate him but did not miss him either, which was worse. He thought about the daughter he had not seen in seven hundred and thirty days. He pushed the thoughts away and focused on the fuel line.

The pipe was cold—colder than cold, the kind of cold that went through the gloves and into the bone. His hands moved mechanically, stripping insulation, cutting the ruptured section, splicing in a replacement from the maintenance kit. The fuel was leaking in a fine mist that froze into crystals in the vacuum, glittering around his helmet like diamonds. He worked for two hours and forty-seven minutes. When he sealed the last connection and checked the pressure gauge, the leak had stopped.

He floated in the dark for a moment, looking at the stars. They were not twinkling. There was no atmosphere to make them twinkle. They were just there—hard, bright, indifferent points of light in an infinite black.

"Tom, come in," Sarah's voice came through the comms. "We have a incoming transmission from Houston. It's—there's something wrong with the signal. It's garbled."

"Put it through."

The voice that came through was Colonel Hayes, their Pentagon liaison, and it was distorted by static and something else—urgency, perhaps, or fear.

"—Prometheus, this is Hayes. Repeat damage assessment. Over."

Tom looked at the fuel line. He looked at the oxygen recycler reading in the corner of his display—sixty percent and dropping. He made a decision.

"Port engine is gone. Fuel line is repaired. We can maneuver. Repeat, we can maneuver."

Silence. Then: "Copy, Prometheus. Hayes out."

The transmission ended. Tom floated for a moment longer, then turned and began the long crawl back to the airlock.

He did not tell Sarah about the oxygen recycler.

The gaps in the data began a week later.

Sarah was reviewing the ship's logs—standard procedure, she said, because she believed in numbers more than people—when she noticed them: three-hour blocks of data that simply did not exist. Not corrupted, not missing. The log files showed that those hours had been deleted. Not by the system. By hand. Someone had gone into the command console and erased them.

"Tom," she said, sitting in the cockpit with the printout in her hand. "What happened between day forty-seven and day fifty?"

Tom was eating a tube of rehydrated beef stroganoff. He looked up. "Day forty-seven to fifty. I think we were in correction orbit. Running the delta-v burns."

"There's no data. Three hours on each of those days. Completely deleted."

He set down his tube. "Maybe the system glitched. Cosmic rays can corrupt memory."

"I checked the hardware. It's fine. Someone deleted those logs."

Tom held her gaze for a second, then looked away. "Sarah, I told you—we can maneuver. We'll make Mars."

She did not look convinced. But she did not press him. She went back to her lab module and closed the door.

Tom waited until he heard her equipment running, then opened the hidden partition on the command console. He pulled up his personal log—the one that was not connected to the ship's main system, the one that Hayes could not access.

He pressed record.

"Personal log, Commander Callahan. Day fifty-one. I have told Sarah the truth about the engine. I have not told her the truth about the oxygen. Hayes called me during the EVA. He told me about the recycler. He told me the replacement part was not on the manifest. He told me there is enough oxygen for one person to make it home. He told me the mission parameters were always one-way. Sarah carries the scientific data. I carry the spare parts. I was always meant to stay behind."

He stopped recording. He stared at the console. The screen glowed blue in the dim cockpit.

"I cannot tell her," he said to the empty room. "I cannot look her in the eye and tell her that I am sending her to die alone and I am keeping the ship for myself."

He deleted the log entry. Then he recreated it, buried in a partitioned drive that only he knew how to access.

Sarah found it three days later.

She had been building a map of the ship's data architecture—tracking every file, every partition, every hidden directory. She was good at this. She was good at finding things that people did not want to be found.

The partition was encrypted, but the encryption was weak—Tom had used a simple algorithm, the kind of thing he had learned in basic training. She broke it in twenty minutes.

The log entry played on her screen, and she read it three times.

I was always meant to stay behind.

She sat in the lab module and stared at the screen until her eyes burned. Then she stood up, walked to the cockpit, and found Tom running diagnostics on the navigation console.

"We need to talk," she said.

They sat in the cockpit, the ship humming around them, the red dot of Mars visible through the viewport. Sarah told him about the deleted logs. She told him about the partition. She told him about the oxygen recycler.

Tom listened. He did not interrupt. When she finished, he was quiet for a long time.

"Hayes told me," he said finally. "During the EVA. He told me the recycler was shot. He told me there was no replacement part. He told me the mission was always one-way."

"Then why did you lie to me?"

"Because I could not bear to watch you accept it."

Sarah stared at him. "Accept what?"

"That you were going to die alone. That I was going to come home alone. That everything we left behind—Earth, Mars, the people who sent us here—everything depends on you getting that data back."

"I didn't ask you to decide this for me."

"You didn't have to. Hayes decided it. I just—" He stopped. He ran a hand through his hair. "I fabricated the engine repair story because I could not tell you the truth. I wanted you to think I was the hero who stayed outside in the cold, when the truth was that I was the man who stayed behind in the dark."

Sarah was silent for a long time. The ship hummed. Mars burned red in the viewport.

"There's more," she said.

Tom looked at her.

"The recycler is not shot. I checked the raw data—the data Hayes tried to hide. The micrometeoroids damaged the thermal shielding, not the recycler. The capacity is at seventy-two percent. It is leaking, yes. But we can fix it. We have the parts. We just need time."

Tom stared at her. "Seventy-two percent?"

"Seventy-two percent. With careful management, it is enough for both of us. We just need to stop the leak and reroute power from the non-essential systems."

Tom felt something move inside his chest—surprise, relief, and beneath both of them, a sharp, clean shame. He had built an entire narrative of sacrifice on a lie, and the truth was simpler and harder and more human than anything he had imagined.

"Why did you lie to me?" Sarah asked again.

Tom looked at her. He thought about the answer he had given before—the one about heroism and sacrifice and the weight of command. It was a good answer. It was the answer he had rehearsed in his head a hundred times.

But he was tired of lies.

"Because I am a coward," he said. "I am a man who spent his whole life following orders and being proud of it, and when I was faced with the one decision that was actually mine, I could not make it. So I made a story instead. A story where I was brave. A story where I was the hero. The truth is, I was just scared. Scared of losing you. Scared of coming home alone. Scared of looking at your face and knowing that I had chosen myself."

Sarah looked at him. Her expression was unreadable.

"Reroute the power," she said. "Show me how to do it."

Tom nodded. He stood up and went to the engineering panel. Sarah followed him. Together, they began the work of rerouting power, sealing leaks, and plotting a course that would stretch their fuel to the absolute limit. It was a gamble. They might both make it. They might both die.

Tom did not think about heroism. He thought about the work. He thought about the oxygen recycler and the fuel line and the specific, concrete problem of keeping two people alive in the dark between Mars and Earth.

Sarah stood beside him, her sharp eyes on the schematics, her hands moving deftly through the connections. She did not speak. Neither did he. They did not need to.

When they finished, Tom checked the oxygen recycler. Seventy-two percent. Stable. The leak was sealed. The reroute was holding.

He turned to Sarah. "We can make it home."

She nodded. "Both of us."

Tom went to the communication console. He opened a channel to Houston. He thought about what to say—about the oxygen recycler, about the deleted logs, about the lie he had told and the truth he had found. He thought about Colonel Hayes and the orders he had given and the weight of a mission that treated people as expendable.

He opened the channel.

"Houston, this is Prometheus. Commander Callahan speaking."

"Prometheus, this is Hayes. Report status. Over."

Tom looked at Sarah. She was standing beside him, her hand resting on the edge of the console, her eyes on the viewport where Mars was shrinking to a smaller red dot.

"Houston," Tom said, "this is Prometheus. We have completed all repairs. Systems are nominal. We are rerouting power and plotting a homebound course. Estimated arrival: ninety-two days. Over."

"Copy, Prometheus. Hayes understands. Good work, Commander. Hayes out."

The channel closed. Tom turned away from the console.

Sarah was watching him. "You did not tell him about the oxygen."

"No," Tom said. "I did not."

"You did not tell him about the logs."

"No."

"You did not tell him about the lie."

"No."

Sarah smiled. It was a small smile, barely there, but it was real. "Good."

Tom went to the communication console one more time. He opened a channel to Houston, but he did not address Hayes. He addressed the public frequency—the one that was recorded and archived and would be read by anyone who cared to listen.

"This is Commander Tom Callahan of the USS Prometheus. I am filing this transmission for the historical record. The micrometeoroid swarm damaged our port engine and our thermal shielding. The oxygen recycler was not damaged. The replacement part was not missing. The mission was not one-way. These facts were known to Colonel Hayes at the time of the incident and were deliberately concealed from the crew. I am not filing this to assign blame. I am filing it because the truth matters, even in the dark, even when no one is listening, even when the only audience is the void."

He closed the channel. He turned to Sarah.

"Send the signal home," he said.

Sarah opened the data transmission. The scientific instruments' readings—Mars's atmospheric composition, the micrometeoroid density, the gravitational anomalies—began streaming toward Earth at the speed of light. But she added something to the transmission, something that was not in the original data packet.

A simple message. Two words.

We are coming.

The ship turned toward Earth. Behind them, Mars shrank to a red dot. Ahead, the void stretched forever, cold and indifferent and full of light.