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.

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.

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!

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.

Joe felt as a man might feel if the mirror of the greatest telescope on
earth, in his care, had been smashed. As if the most pricele