He crawled to the back of the ledge. He worked his way along the ridge, setting out his instruments, little tin-can boxes containing sensitive seismometers, shrouded in thermal blankets. The seismometer signals would be analysed as real-time data and in terms of frequency to record the ground’s vibration. He set up combinations of theodolites and electronic distance meters that might give some clue as to the deformation of the ground, even here on the side of the rille. And he deployed, close to the rim of his ledge, a small cospec, a correlation spectrometer, that would be able to measure emission rates of any gases it could detect. The instruments would be connected to a central data collection and communications unit and batteries by multiplex cables, that he plugged into the backs of the boxes.

All these instruments were improvised from lightweight gear deployed by VDAP to gather real-time data on volcanic events. It was true that what he was investigating here was no volcano, but even volcanology was a young science; he hadn’t had any smarter ideas on what to bring here, to this infestation on the Moon.

He actually enjoyed setting up the science gear: plugging cables into their sockets, testing power couplings and data transmissions. It was simple work, no more complex than putting together a back-yard barbecue. Yet it was good for his soul to have some familiar tasks to get through, here amid all this strangeness. He moved between the instruments, the fans of his backpack whirring, the oxygen blowing cool over his face.

When the science station was set up, he stepped back from it, towards the edge of the basalt ledge. He ran his eye over the connections one more time, making sure he hadn’t missed something dumb, checking all the power lights were switched on. He didn’t want to have to come back down here and fix anything.

However, it all looked fine. Now all he had to do was climb out of here, trailing a comms link cable behind him, so the station could talk to the surface, and so to Earth and the shelter.

But there seemed to be a softness, beneath the tread of his right foot.

He looked down sharply. He was maybe four feet from the lip. But suddenly the rock surface was crumbling like wet sand.

The last three or four feet of the ledge just disappeared, in a half-circle extending maybe a yard around him. Under a surface of some kind of duricrust, he realized, this whole ledge was rotten with Moonseed dust. Suddenly he was falling, amid a cloud of dust, and there wasn’t a damn thing he could do about it.

Moonseed sparkled in the light of his torch.

Falling on the Moon:

Dreamlike slowness.