She called up the schedule of things still to be done, then the duty roster, saw it had been rearranged again. She was to join April and Calvin outside. She hurried to the lock.

Her suit was bulky and tight. it murmured at her while the radio hissed quietly. it smelled comfortably like herself, and like hospital plastic and fresh oxygen.

Ringmaster was an elongated structure consisting of two main sections joined by a hollow tube three meters in diameter and a hundred meters long. Structural strength for the tube was provided by three composite girders on the outside, each of which transmitted the thrust of one engine to the life system balanced on top of the tube.

At the far end were the engines and a cluster of detachable fuel tanks, hidden from sight by the broad plate of the radiation shield which ringed the central tube like the rat guard on the mooring line of an ocean-going freighter. The other side of that shield was an unhealthy place to be.

On the other end of the tube was the life system, consisting of the science module, the control module, and the carousel.

Control was at the extreme front end, a cone-shaped protuberance rising from the big coffee can that was SCIMOD. It had the only windows on the ship, more for tradition than practicality.

The Science Module was almost hidden behind a thicket of instrumentation. The high-gain antenna rose above it all, perched on the end of a long stalk and trained on Earth. There were two radar dishes and five telescopes, including Gaby's 120-centimeter Newtonian.

Just behind it was the carousel: a fat, white flywheel. It rotated slowly around the rest of the ship, with four spokes leading up from the rim.

Strapped to the central stem were other items, including the hydroponics cylinders and the several components of the lander: life system, tug engine, two descent stages and the ascent engine.