When he had first arrived here he had asked if he could choose which module he based himself on or each of his visits. The base commander had looked at him oddly and said that they were all identical. The caretaker had explained what the difference was and that as he would be alone for a month on each visit even a slight change was better than nothing.
The scientists and other base personnel had left for warmer climes the next day and he had wandered from module to module powering them down. Off went the water, the cooling, air handling, all lighting, except for the green LEDs that marked each emergency hatch. From now on he would have to put on his environmental suit just to do his daily inspection of each module. Only the module he had chosen, Bird's Nest, would have heating and life support from the stored solar energy in the batteries,
As soon as the sun had set on the first day the outside temperature had fallen from 123C, above that of boiling water, to a numbing minus 153C, cold enough to freeze alcohol, not that either liquid could have existed in the vacuum outside the base. The modules had creaked and groaned as they cooled for several days. Even with the thick layers of insulation protecting the base as the internal temperatures dropped below freezing all the surfaces glittered in his headlamp with frost condensed from the air. After a few days the noises had stopped and he was alone in silence, until today.
The comm system had woken him at 6am GMT, time zones were irrelevant here but they had long ago standardised to one system for all the bases. A bounced signal off a satellite allowed him to send in his report from the previous day. It basically told them that he was still here, as if he could be anywhere else. Just what the other base would do if he missed a report nobody had ever mentioned. He had to hope that they would come and see, if only to drop off another caretaker.
After breakfast the caretaker suited up. Body heating system, breathing air heater, water bottle, torch batteries, all checked out. Time for a walk in the cool dark of the modules. Should he go clockwise or counter-clockwise? Time to toss a coin. Clockwise, so Daffodil, Tulip, Bluebell to start with, then back for a coffee, another 4 before lunch, then split the afternoon between the remaining 8.
It was as he entered Daffodil that he thought he heard the noise first. Not easy to know if it was his own breathing in the suit or something inside the base. It was odd, an air leak in the base would be a continuous noise and anyway any pressure drop would have set off the alarms. He circled the module and checked all the side rooms. Nothing unusual. He shrugged, perhaps he was just hearing things. He headed towards the exit and heard it again. No doubt this time. But what was it ? ...