Hannah looked across at him, saw more blood running from his scalp, and watched as his eyes folded up into his head, exposing their whites. Despite wearing the same sort of suit as she did, he was blacking out, but she could do nothing for him just then . . . or perhaps ever.

At first the whole structure seemed like a toy, and only by seeing another space plane, like the one they were aboard, clinging to one of the massive docking pillars stabbing out into space, like an iron redwood growing from the station rim, could he recalculate the scale. An object moving across the outer surface of the station wheel, which he had at first taken to be someone in a spacesuit, he now realized must be some sort of vehicle or robot the size of a bulldozer.

A big technical control centre had been built on what might be described as the top of the asteroid, which sat at the centre of a three-quarter ring five kilometres in diameter and over a kilometre wide and deep. Three cylinder worlds held this ring in position, each of them a kilometre wide and nearly two kilometres in length, spaced at three quarters like spokes, their near ends connected to the asteroid itself, whilst at the fourth quarter, projecting from the rocky surface directly towards the break in the ring, sat the massive Mars Traveller engine.

Two further spokes were positioned evenly in the two gaps between the three cylinders. These were the two ore transit tubes that ran from the asteroid’s surface to connect with the smelting-plant docks located in the rim. Extending out from the plant docks, on massive cables, were the smelting plants themselves, positioned about a kilometre out from the station – these looked something like giant combustion engines surrounded by a spider-web of cables and further scaffolding to support the foil parasols of folded or unfolded sun mirrors, all again surrounded by vapour spilling from the processes conducted within.

Up close, Argus certainly did not look so neat as it did from the surface of Earth, and it now seemed much larger than the last government-approved images of it that he had viewed. The sections between the spokes, from the asteroid to the station rim, were infilled with lattice walls with numerous accommodation units and other features sandwiched between, all connected by tubeways through which ran wormish trains. The levels expanding outwards from the original wheel were not being built one at a time, so in some areas three or four ‘floors’ of the station extended out into space, webbed throughout by structural members, with random chequer-square sheets of bubblemetal scattered across them. In fact there seemed no clear dividing line between where the station ended and space began.

‘Keep your head still,’ Hannah instructed.