He finished his list and activated his instruments, then sat back and hummed, drumming on the arms of his acceleration couch to keep time, as his on-board computers flickered through the mission programs. It was always possible to hit a glitch, but there was little he could do about it if it happened. He was a pilot, thoroughly familiar with the electronic gizzards of his one-man Beagle Three survey vehicle, but he had only the vaguest idea about how this particular instrument package functioned.

The rate of technical progress in the seventy years since Armstrong was enough to leave any non-specialist hopelessly behind outside his own field, and the Geo Sciences team back at Shepard Center had wandered down some peculiar paths to produce their current generation of esoteric peekers and pryers. "Gravitonic resonance" was a marvelous term... and MacIntyre often wished he knew exactly what it meant. But not enough to spend another six or eight years tacking on extra degrees, so he contented himself with understanding what the "planetary proctoscope" (as some anonymous wag had christened it) did rather than how it did it.

Maneuvering thrusters nudged his Beagle into precisely the proper attitude, and MacIntyre bent a sapient gaze upon the read-outs. Those, at least, he understood. Which was just as well, since he was slated as primary survey pilot for the Prometheus Mission, and—

His humming paused suddenly, dying in mid-note, and his eyebrows crooked. Now that was odd. A malfunction?

He punched keys, and his crooked eyebrows became a frown. According to the diagnostics, everything was functioning perfectly, but whatever else the moon might be, it wasn't hollow.