by Baen Books
“Listen to yourself. This entire mission is for the sake of science.”
“You mean so much more than that,” Ryan said. The words spilled out of her crewmate in a rush. Blake could hear the desperation in the man’s voice.
“Ryan, I . . .” Her voice was softer now, sympathetic. “Can you move us to a private channel?”
Blake didn’t hesitate.
“Don’t worry about me. Do what you need to do.”
While the message was flying through space toward the red planet, Kate and Ryan continued their private conversation. With her golden visor in place, he could not see her expression, but her body language was clear. She was trying to tell Ryan to let her go, to give her up.
Blake slouched forward in his chair, thinking. He was not thrilled about someone scrapping Feldspar for parts; in fact, it was a recurring nightmare of his. But he would sacrifice anything to give Kate a chance.
Even as the thought echoed through his head, he realized there was something else he could sacrifice, something worth far more than a few hours of heat and air. It would give her more than just a chance.
A surge of hope straightened his back, and he scrambled at the touchpads. He tried to keep the smile from his voice.
“Also, if it’s any help, I have an insulated shelter about seven kilometers from here with two fully charged batteries and a tank of compressed oxygen.”
She went completely still when his message arrived and then shook her head slowly and gave a small shrug. A second later, Ryan’s voice came back on the channel.
“Hey kid, are you serious?”
“I think we have to assume he is,” Kate said. “What other choice is there?”
“You can scrap him.”
“Fine, I’ll scrap him if he’s lying,” Kate said in exasperation. “But if he’s telling the truth, I could have a place to stay while Svetlana and Dave come for me.”
Ryan sighed. “What are the coordinates?”
Blake read them aloud. He’d never given them to anyone before, and he couldn’t help but feel like all of his secrecy these past few years was for nothing. After today, everyone will have heard of Feldspar’s hidden home.
When the transmission arrived, Kate laughed. “That’s near Dromore crater.”
“I guess you’ll have a chance to see it after all.”
Rather than wait for NASA’s approval, Kate began to hobble in that direction on her new crutch.
Blake reinitiated his previous navigation protocol as Kate took the lead, creating tracks for him to follow. While the crutch helped her maintain a steady pace, he could tell by her winded conversation with Ryan that the seven kilometer distance pushed her to her limits. The deepening drifts of sand and the slight increase in elevation as they approached the crater’s rim tested her endurance even further. Rocks were strewn across the barren ground, their size and proximity causing Feldspar to pause and adjust navigation on several occasions.
During the last leg of the journey, Kate made a dismayed sound.
“CO2 scrubber is maxed out. My suit’s gonna start purging air to keep the CO2 levels below one percent. That’ll only last as long as I have oxygen and nitrogen to replace it, and I don’t have much.”
“We’ll see you through this, Kate,” Ryan said soberly, and then his voice became businesslike. “Feldspar, how much oxygen do you have, precisely? And what kind of fitting does the regulator have? NASA will send you more questions any minute now so check your inbox. They’ve also sent you the specs for the suit’s hose fittings. If it won’t fit your tank, you’ll need to print a suitable adaptor.”
Sure enough, the specs were already in his inbox with a fancy NASA header and the word “confidential” in large, red letters. Someone had made the adaptor with compatible design software, and the message asked him to add the female end for his tank. Blake promptly replied to the message, stating that he would just weld it onto the tank’s outlet to save time and ensure a better seal.
Dozens of other messages and inquiries about his shelter arrived immediately after his response. Blake did his best to address them all, but soon gave up and sent all of his detailed schematics. He felt a little violated at the thought of dozens of techs pouring over the designs he’d spent years perfecting.
Blake put NASA out of his mind long enough to respond to Ryan.
“I received it. I should have enough metal to make adaptors for both the oxygen and nitrogen tanks. Both are about forty liters large and average one thousand PSI.”
When Blake’s transmission went through, Ryan sputtered in disbelief.
“Nitrogen? I’ll buy that you somehow managed to print a tank and that you’ve pressurized it with oxygen, but nitrogen? What is the concentration in the atmosphere? Two percent? How could you possibly separate it from the other gasses?”
“Zeolite,” Blake said. “And a few other aluminosilicates. At high pressures, nitrogen sticks to the mixture. When the oxygen moves into the second tank, the pressure drops, and nitrogen is all that remains. I repeated the process hundreds of times. It should all be pressurized nitrogen. The regulator is something I’ve had to build myself, but I salvaged the compressor from another rover’s AIR module.”
“He’s right,” Kate said when his response arrived. “We have a similar system at Base Camp. Space stations and hospitals have been using zeolite for decades to concentrate oxygen and capture nitrogen. It’s called pressure swing absorption.”
“Where the hell’d he get zeolite?”
“I suspect he did his research before Project Regolith started. That’s why he named his rover Feldspar,” Kate said. Blake smiled. No one had ever puzzled out the origin of his rover’s name before. The last person he’d told had assumed it was named after some dwarven hero in a fantasy game.
“I’m confused.”
“Feldspar is a family of minerals called aluminosilicates,” she explained. “Project Regolith only had their sights on the iron in the dirt, so he found a use for the rest, the stuff they were just throwing away. They call it slag.”
Ryan made a sound that Blake could only describe as grudging agreement.
“I suppose you’re right. NASA just forwarded the schematics for the shelter. Get this; he’s filled all of the walls with slag. According to NASA, it’s as good an insulator as you’ll find on this planet. He even filled a pit with the stuff because it’s porous and effective at leaching water from the ground.”
“Are all Project Regolith rovers this resourceful?” She sounded breathless.
“Hardly. That friend I mentioned? He went by the name Lugnut and spent years printing a vintage car that has no chance of running.”
“It’s as if our rover operator intended to live here one day,” Kate said.
“You should really look at this thing, Kate. The schematics are like nothing I’ve ever come across.”
“I think I do see it . . .”
Beside Dromore crater was a wide but shallow canyon created by one of many ancient waterways that crisscrossed this region of Chryse Planitia, an area called Maha Vallas. A unique feature stood out among the others as they descended into the canyon. Imbedded in the wall of the ancient waterway was a flat, circular door. Years of exposure to the elements had tarnished its surface, but it still glimmered in the fading sunlight.
“Yeah, that’s definitely it.”
“I shut down the camera feed to conserve power. What are you seeing?” Ryan asked.
“It looks like an airlock. It’s set into the side of a rock face. Feldspar, did you dig through the rock somehow?”
Blake leaned closer to the microphone at the base of the display, but Ryan already had the answer.
“From his notes, NASA thinks it was an old lava tube that was exposed by erosion. It might even be an old water plug that slowly sublimated and formed a cavern. He’s reinforced the whole thing and sealed it off.”
“How do I get in?”
“Leave the entry to me,” Blake said.
They had moved to the very base of the door by the time the transmission went through. Kate dropped her crutch and sat down, leaning her back against the edge of the door.
Feldspar initiated the entry sequence. It rolled to a stop beside the large door and extended its manipulator arm. The pincers spread apart and inserted into a recess that was perfectly shaped to receive it. A small hole between the pincers led straight to the rover’s AIR module. The purpose of this feature was to air-dust the clingy sand from joints and solar panels. Instead, Feldspar sent the compressed oxygen into the door, where it fed into a piston near the hinges. The pressure drove the piston outward, easing the large door open.
Kate let out a low whistle and stood to peer through the widening gap. She limped around Feldspar and took a step inside.
“There’s a type of rubber surrounding the door. It’s a gasket, I think.”
“According to the schematics, they’re from the wheels of several salvaged rovers,” Ryan supplied.
“Will I lose coms if I enter?”
“Don’t think so. He’s had to operate in there too, remember. It looks like he’s placed an antenna from a rover out the top of the enclosure, on the edge of the chasm. There are salvaged solar panels up there too. That’s how he’s able to charge the batteries. Damn, this kid’s thought of everything.”
Feldspar’s automated sequence led him into the enclosure after Kate and then to another port. The rover repeated the previous sequence, but this time the pressurized air drove the piston in the opposite direction, closing the door.
Darkness engulfed them for an instant until Feldspar’s night navigation sequence activated, and a light on his camera module switched on. The space was only about as large as the room Blake sat in, except that all the corners were rounded and shone with a dull, metallic gleam.
There was a second, inner door to the airlock, which Feldspar usually left open, but they needed all the insulation they could get.
As Feldspar closed the second airlock door, Kate explored the small room. Her breathing was becoming strained, and her teeth were chattering. She succeeded in locating the narrow shelf holding the batteries. Several spliced wires, harvested from broken-down rovers, led from the batteries and up to disappear into the ceiling.
She removed her pack, dropped her crutch, and sat down beside the narrow shelf. She pried open the outer covering of the pack to expose tanks, wires, and hoses. Several minutes passed as she tried to pick up the battery leads and press them in to her own battery. The thick gloves and her undoubtedly numb fingers made progress slow.
“I can take control of Feldspar from here and operate him in real time. I can help you connect the battery leads. I’ve already patched into his camera, and the controls seem pretty straightforward.” The tension in Ryan’s voice suggested he was just as concerned as Blake.
“No, Ryan. The delay is annoying, I know, but he’s the only one who knows what he’s doing. Now, what’s the plan to get me more air? My nitrogen and oxygen are almost depleted.”
“Working on it,” Ryan said, even as Feldspar’s next sequence arrived, steering the rover around and toward the opposite end of the room.
Blake lined up one of the tank’s regulators in the display and pulled the hose adapter design from his software. He oriented it on the surface of the tank’s outlet and finalized it.
Kate sighed in relief.
“All right. My heaters are back online.”
The tungsten tip of Feldspar’s 3D printing arm grew white hot and cast a dim light on the wall. It eased closer to the tank’s outlet nozzle and began to deposit a thin layer of molten iron. It continued in a circular motion, leaving a line of glowing metal in its wake.
“Bad news. I’m out of gas. The CO2 will build up rapidly now that I can’t purge it.”
“So soon?” put in Ryan. “That can’t be right.”
“I was thinking the same. I suspect the crash damaged one of the tubes connecting my suit to the oxygen and nitrogen tanks. I must have lost a little every time the suit filled during a purge.”
“Feldspar, what’s the time estimate for those adaptors?”
“Twenty minutes tops for the oxygen tank adaptor. That is, it will take another twelve minutes once this message reaches you. It’s a higher precision print than the crutch because of all the fine detail.”
Every few minutes, Kate updated them on the CO2 percentage. It rose from 0.4 percent to 1.5 percent before his transmission went through. At each update, he felt as if the hand of a large, unseen clock was counting down to Kate’s death. The delay was not helping. What he was seeing and hearing was happening eight minutes ago, and he was powerless to step in and intervene.
“CO2 is three point one percent. Oxygen . . . ten percent,” she said. Her words were lethargic.
“All right Kate. I’m gonna need you to head over to Feldspar, he’s almost done with the adaptor,” Ryan said after a short pause.
Blake leaned back and sighed. If those words left Mars eight minutes ago, it was likely Kate had already connected her line and was breathing oxygen. He had done it. He had come across an astronaut in the middle of Chryse Planitia and helped her stay alive.
“Kate? Do you read?”
Blake sat up, but he couldn’t hear anything except for the faint sounds of breathing.
“Damn it. Stay awake, Kate,” Ryan said.
Silence greeted the command.
The video feed continued to show a view of the oxygen tank as Feldspar printed the last section of the adaptor. A moment later, a red light flashed beside his status display.
Then Feldspar was moving on its own. Blake tapped his touchpad, but the system was unresponsive.
Ryan had taken control of Feldspar.
Blake stared in rising horror as Ryan steered Feldspar back to the shelf holding the batteries. Kate remained slumped against the metal wall next to it, unmoving.
“Damn you, Kate. Wake up. I’ve seen you handle ten percent oxygen before. You can do this.”
Feldspar’s manipulator arm jerked upward and then back down before Ryan gained control. The pincers reached out and prodded Kate’s motionless form. When she didn’t respond, the pincers opened and gripped her pant leg and tugged.
She didn’t move.
Mind racing, Blake pressed the transmit button.
“Ryan, I have an idea. Give me control,” he said. He programmed a sequence, his fingers darting across the touchpad. He had no time to triple check, no time to double check. He sent the sequence.
Ryan continued to tug at Kate’s suit, but the rover was barely half her size and she didn’t move an inch. He let go of the suit and gripped a hose from her open pack. He was trying to stretch the hose all the way to the oxygen tank. He was desperate.
A message appeared on his display. NASA was politely requesting that he not take any recordings or pictures and “respect her family’s privacy” by not going public.
Blake gritted his teeth. They had already given her up for dead.
He keyed in another command sequence, letting his patience and better judgement fade into obscurity as he acted on impulse.
A few moments after his message reached Ryan, the rover continued to try to wake Kate, going so far as to press its pincers into her injured leg.
“Kate! Wake up!” Ryan screamed over the coms.
The radio was silent but for Ryan’s panting and sniffling, and Kate’s labored breathing.
“Take it.”
And then Feldspar was his.
His prepared sequence delivered, Feldspar wheeled around and drove back to the oxygen tank. It extended its arm and reached toward the regulator. Gripping it with its pincers, it lowered the lever with painful slowness. Gas rushed out of the tank. He couldn’t hear it, but the pressure of it escaping created a small cloud of water vapor at the mouth of the tank. Feldspar’s arm swiveled to the right and gripped another lever, and Feldspar rep
eated the process with the nitrogen tank.
A moment later, Blake’s next sequence arrived and the rover’s AIR module opened. It evacuated all of the oxygen within its tank into the enclosure. Rather than close the port, he left it open, exposing the module’s sensors to the ambient air. Oxygen and nitrogen, which had been at a measly two percent a moment ago, were steadily climbing in time with the PSI.
After a handful of readings came in, he programmed Feldspar to cut off the gas when the oxygen and nitrogen reached normal levels and the PSI reached 14.7. He then compiled his riskiest sequence yet. His finger hovered in the air for a minute, and then it mashed the send button.
The pressure in his enclosed shelter continued to rise.
“It’s hopeless,” Ryan said, his voice soft. “Her oxygen is down to eight percent and her carbon dioxide is up to six. She doesn’t have any time.”
Blake cursed. Even Ryan had given up on her.
When the pressure reached one atmosphere, Feldspar lowered the levers on the tanks’ regulators and spun to face Kate’s prone body. Its six wheels eased across the small room and stopped before her.
“Feldspar?” Ryan asked.
Once more, the tip of the 3D printing arm glowed with heat. It extended outward, toward the golden faceplate.
“Feldspar!”
The golden face-shield reflected the glowing point with clarity until it made contact. Seconds later, the glass cracked and began to glow red and warp around the probe.
Blake no longer touched his controls. He pressed his palms to his stubbled cheeks and stared through the narrow gaps of his fingers.
The only sound was a sudden hiss from the coms.
Then the glow stopped and the arm retracted.
A perfect hole, no more than a centimeter wide, was melted into the face-shield.
He checked the AIR module’s readings: 21% O2, 78%N2, and 1% CO2. 14.7 PSI
Kate was still.
A lump formed in his throat, and he held his breath.
A gloved finger twitched, and then an entire arm began to move. It lifted to the helmet, and fingers prodded the hole melted into the faceplate.
Kate searched the neck for small clasps and then lifted the helmet to reveal a narrow, pale face with short-cropped hair.
