Manning went on, "We cannot tell, of course, at what point in the collapse the survivors made their escape. We know that the automatic circuits begin deceleration as soon as the warp-generator shows signs of failure, the hope being that the spacecraft will fall to a safe velocity before the field collapses completely. Therefore escape could be made at any velocity between forty parsecs per hour, if they escaped before the deceleration began, or at normal under-light velocity, which might take place if the spacecraft had succeeded in dropping to safety before the field collapsed. However, in that case, there would have been no explosion and our space wreck victims would have remained in the spacecraft, or returned to it as soon as they saw it was safe. Therefore, integrating the probabilities outlined here, the survivors must lie between the planes of maxima and minima, representing escape at maximum forward velocity and minimum forward velocity. Here, gentlemen, is your search grid."
The rest of the stereo-field went out, leaving the white lines of the grids. Lateral lines now appeared to connect intersections of the fore grid with the corresponding intersection of the aft grid.
"We are here."
Tiny discs of purple dotted space before the small end grid. The discs were flat-on to the grid and represented the maximum distance for space detection of matter.
Wilson felt something touch him on the arm. He turned. A tech-operator standing there had a bewildered look on his face.
"Yes?" said Wilson.
"I'm puzzled, Commodore. Suppose we don't find them in a long time. Won't that far grid have to be pushed back?"
"No," Wilson explained wearily. "The function of a lifeship is to get its occupants down below the velocity of light and then coast. Since that grid represents a total distance of about ten light years, they'd have to be floating for ten years at the velocity of light to make it. Any normal speed, over a period of weeks, would hardly appear long enough to cover the thickness of one of the grid lines."
"Ten light years!"
Wilson nodded and repeated. "This is no picnic." He turned from the tech-operator to the planning table. "Unless someone has a better suggestion, we'll set up a hexagonal flight pattern with a safe detector overlap and start by cutting a hole down through this grid volume along the prime axis. Anybody got any other suggestions?"