Jarvellis ignored the voice, put her helmet on and twisted it into place. Maybe the seals would not work so well. Maybe they would work for long enough. She opened the valve on the air bottle and got a hiss of air that was breathable, but had a vaguely putrid smell.

‘Captain, please come out of that lock. Very little of the equipment there has been serviced. You could kill yourself . . . oh, I see . . . I wouldn’t advise trying to use that shuttle. It has no AG, you realize? Those ion eng . . . you . . . s . . . t . . .’

The inner lock was irised. It made no noise as it opened, but that was because there was now no air to transmit sound. Neat way of shutting Tull up anyway. Jarvellis stepped out of the lock and hurried over to the shuttle. The door she saw was not a door with an airlock. She twisted the two handles at the side of it and hinged it open. It was a single-seal door; only with it closed would the shuttle fill with air. Back when this station was constructed, weight had played an all-important role. A full airlock would have been too much extra. Jarvellis stepped inside and closed the door. White vapour was now leaking from the folds at the elbow of the primitive suit. It was also leaking out round the neck-seal and painting glitters of frost across the plastiglass.

The cabin of the shuttle was simply a plain box, with spring fixings along the floor to take either chairs or cargo straps. Ahead there was another hinged door. She moved quickly to it and tried to turn the handles. Nothing gave. She put her weight on the handles, and they started to move just before her feet left the floor. She pulled herself down and jammed her foot in one of the spring fixings to try again. Vapour bloomed around the door, then dissipated. She got it open and pulled herself in. Even as she closed the door, she found herself panting for air that was getting increasingly thin. A button. Cycle. She hit it and dragged herself to a dusty seat before the console and control column. She searched for a readout and found it above the door. The readout was in bar and she was not sure what was required. She cracked open the helmet when vapour ceased to flow from the seal. No difference now anyway; there was little left in the suit.

‘Captain Jarvellis . . . Jarvellis . . . I hope you can hear me. Can you hear me?’

‘Yes, I can hear you, Tull,’ she said.

‘Good,’ said the Outlinker. ‘Now, just so you don’t kill us all by trying to start those ion engines in the station, I’ll tell you how to use the magnetic impeller. It’ll get you out of that bay and away. Beyond that, you’re on your own.’