While she was thinking about it, the compressor stopped and it got a lot quieter in the cramped space. The gas system must have put back enough oxygen in the storage tanks to raise the pressure again. Kate thought about that. “If it’s refilled the tanks, the leak rate must be pathetic.” She was hoping the hydrogen would flow continuously into the hab until the level was back up, and then she could go outside and shut off the oxygen leak. There was a really large volume to fill and she was sure it would take ages even with the compressor running full time.
Kate sat down and leaned back against the hull wall intending to wait for the compressor to come back on and get an idea of the duty cycle. If she could estimate what percentage of the time it was running, that would give her an idea of how much more oxygen she needed to let out. She felt really tired and closed her eyes for a minute. It was uncomfortable on the hard floor with the cold wall behind her, which was just as well. She needed to wait for the compressor to come back on, not sleep. She tried counting. “One one thousand, two one thousand,…” but got bored quickly. Then the compressor started back up. “OK, so how long was that? And how long had it been running before it shut off?”
She guessed it had been running since she was outside and perhaps it had been off for about half that time. Maybe a little more? It was very hard to judge. She sat and thought about it for a while. She tried to calculate the percentage increase in the oxygen venting rate she needed, but was having a lot of trouble with the math. “Never my strong suit,” she thought. She tried again but felt weird, spacey, like she was about to pass out. “Get out of here!”
Kate rolled over forward onto her hands and knees and crawled the few feet to the hatch. When she got there she lay flat on her belly and let her head hang down through the hole. She breathed deeply a few times and instantly felt better. She got up and descended the ladder into the ops room. “That was stupid.”
She had realized she was anoxic because the low density hydrogen was filling the mechanical space and all the oxygen was being forced down out of the hatch. Well, at least she had enough hydrogen in the mix! But that made her think about how the system kept the gas mix at the right levels. Surely the hydrogen and helium would float to the top and all the oxygen would settle at the bottom.
Fans, there must be fans to circulate the gas mix.
“What the hell is the matter with you? Of course there are fans. They make the noise that fills the hab all the time. How could you not know that?” She realized that the mechanical space was normally sealed off and had no fans. She sat down on the mattress and listened. She was so used to the noises of the hab by now that she had to pay attention to hear them. The fans were running but she still didn’t feel right.
Kate rolled off the mattress and turned on the scuba cylinder she had been using, put the regulator in her mouth, and breathed deeply for a few breaths. That felt better. She put the scuba rig on and walked over to the console. The gas mixture screen showed that the hydrogen level was way above where it should be. “Oh crap.” She looked at the clock. Two hours had gone by since she took the readings. “Did I pass out? Oh shit!”
She took the scuba gear off keeping the regulator in her mouth. Thank God for dive training. She could breathe through the regulator while keeping her nose blocked off without the need to pinch it with her fingers. A skill that was taught for survival in the case your mask was kicked off by another diver. She laid down the scuba rig and took a deep breath. Holding her breath she dropped the regulator from her mouth and grabbed the dive suit. She got it half way on in one breath then used the regulator to get a few more before holding it again to zip up the suit.
Once she was suited up she checked she had the big wrench secured to the BC and ran through the checklist on the wall. “Dive light. Where is the light?” It was clipped on the wrong side but at least it was there. “Let’s go.”
Kate tried hard not to swim fast. “Be cool girl.”
At the top of the hab she put the wrench back on the loose fitting and rotated it closed until there was just a small leak. It wouldn’t close any more than that. She had no way to get enough purchase in this direction. The leak was tiny. It would have to do.
On the surface Williams was hovering over the technician in the comms shack. There was still nothing on the ELF radio screen. His mind was full of desperate thoughts. He just wanted to know what was happening. He’d settle for just knowing that Kate was still alive.
The tech. looked at him. “Why don’t you get yourself some coffee sir? I’ll let you know the instant we get any messages.”
“What? Yes. OK. Good idea.” and Williams left. The technician thought that more coffee might be the last thing Williams needed but her was fed up with the pacing.
Williams found Dr. Subramanian in the galley nursing a cup of tea and chatting with the engineers.
“Any news Dr. Williams?” Subramanian asked.
“No. Nothing. I am very worried about Dr. Moss.”
“Of course. But I suspect she is working on the problem and has not had the time or the inclination to send us a message.”
“How can you be so dispassionate about this?”
“I have plenty of passion Dr. Williams, but I am also a pragmatist. Whatever is happening down there is what is happening. We have no control. Speculation is pointless, unless you wish to make a wager. Are you a betting man Dr. Williams?”
“No, not really. Do you think she is coping?”
“Oh yes. Unless some further problem has developed, I believe Kate will let us know when she has completed the task and has something positive to report.”
In the Pheia, Kate stood at the console still in her dive gear and breathing from the regulator. She typed out a message to send to the surface: “Survived passing out from anoxia. OK now. Shut oxygen leak off. Taking measurements. Will report shortly.”
The technician jogged down to the galley and stuck his head through the door. “A message from the Pheia.”
Williams got up. “What does it say?”
“I guess she’s OK, but you should read it for yourself.”
Williams and Subramanian walked into the comms shack. Williams read the message.
“Oh my God. She passed out. How the hell did that happen?”
He left Subramanian to read the message for himself and went back to the galley to talk to the engineers.
When he got there, they were having an argument in French. Williams sat down and they stopped talking and looked at him.
“Kate says that she passed out. How could that happen?”
Babin considered the question. “I can think of at least five or six reasons. Do we have any other data?”
“No. Nothing.”
“Then I do not wish to simply guess,” Babin said.
Williams told them he was expecting more data soon and left for the comms shack again.
Kate reviewed all the gas system screens and built up a log entry with all the data. When she was sure she had it all, she sent the message. “That should keep them busy for a while.”
She looked at the gas mix levels again and took out the regulator. The mix was OK now as far as she could guess. The fans must have mixed it better now and the levels had stabilized.
The air seemed OK to her. She breathed it for a while and tried to assess her own mental state. “Fried, I think.” she thought and managed a smile.