There were only two things Pirx could fire from the cabin: himself and a balloon probe. The patrolships were designed such that a pilot could eject himself in his encapsulated seat, together with a braking chute. This was done only as a last resort, and obviously there was no going back once a pilot had bailed out. That left the balloon probe—a remarkably simple device, consisting of a thin-walled rubber balloon that when deflated rolled up tightly enough to be a spear. To enhance its visibility, it was treated with an aluminum coating. Sometimes a pilot has a hard time telling by his aerodynamometer readings whether or not he has entered a planet’s atmosphere. Most importantly, he will want to know if any rarefied gas is lying in his path. When in doubt, he will fire the balloon, which inflates automatically and travels at a speed somewhat greater than the ship’s velocity. Because of its brightness, it is visible to the naked eye from as far away as 5 to 6 kilometers. If it encounters rarefied gas, the friction will cause it to heat up and explode. That’s when the pilot knows it’s time to start braking.

Pirx did his level best to aim the ship’s nose directly at the milky-white disk. Without the radar to guide him, he had to rely on the telescopic range finder. But trying to hit a target that size from a distance of almost 2 kilometers is no mean feat. Whenever he went to fire the balloon, the little disk would slip out of the line of fire. And no sooner would he bring his nose around, gently feathering his yaw jets, than the disk would do a nifty little sidestep and pop up again in the center of the screen. It repeated this maneuver four times in a row, each time with greater speed and facility, as if it were already starting to second-guess him. And judging by the way it flew slightly off course, at an angle, it was clear the disk had no intention of letting the AMU-111 fire point-blank at it.

This was fantastic. To react to such minute changes in his ship’s attitude, at a distance of 200 meters, the disk would have had to be using a telescope of gigantic proportions—of which nary a trace. But not only was it capable of carrying out a tricky evasive maneuver, it did so with only a split-second delay at the most.