The pilot gyros of the Space Platform would apply the torque that would make the main gyros shift it to any desired position, or else hold it absolutely still. They were to act, in a sense, as a sort of steering engine on the take-off and keep a useful function out in space. If a star photograph was to be made, it was essential that the Platform hold absolutely still while the exposure lasted. If a guided missile was to be launched, it must be started right, and the pilot gyros were needed. To turn to receive an arriving rocket from Earth....

The pilot gyros were the steering apparatus of the Space Platform. They had to be more than adequate. They had to be perfect! On the take-off alone, they were starkly necessary. The Platform couldn't hope to reach its orbit without them.

Space Platform — Part 37

Joe chipped away charred planks. He pulled off flame-eaten timbers. He peeled off carbonized wrappings--but some did not need to be peeled: they crumbled at a touch--and in twenty minutes he knew the whole story. The rotor motors were ruined. The couplers--pilot-to-main-gyro connections--had been heated red hot and were no longer hardened steel; their dimensions had changed and they would no longer fit. But these were not disastrous items. They were serious, but not tragic.

Space Platform — Part 37

The tragedy was the gyros themselves. On their absolute precision and utterly perfect balance the whole working of the Platform would depend. And the rotors were gashed in one place, and the shafts were bent. Being bent and nicked, the precision of the apparatus was destroyed. Its precision lost, the whole device was useless. And it had taken four months' work merely to get it perfectly balanced!

Space Platform — Part 37

It had been the most accurate piece of machine work ever done on Earth. It was balanced to a microgram--to a millionth of the combined weight of three aspirin tablets. It would revolve at 40,000 revolutions per minute. It had to balance perfectly or it would vibrate intolerably. If it vibrated at all it would shake itself to pieces, or, failing that, send aging sound waves through all the Platform's substance. If it vibrated by the least fraction of a ten-thousandth of an inch, it would wear, and vibrate more strongly, and destroy itself and possibly the Platform. It needed the precision of an astronomical telescope's lenses--multiplied! And it was bent. It was exactly as useless as if it had never been made at all.