AVIATION: Go! Go!

In the cold, rarefied upper atmosphere nine miles above California's Mojave Desert, the B-52 mother ship let go of the stub-winged X-15 research plane and swung away. In his cramped cockpit, greying Test Pilot Joseph Walker, 38, flicked a series of switches, and the black needle-nosed X-15's eight rocket chambers roared into fiery life. On a high-altitude research mission for the National Aeronautics and Space Administration, Walker was not supposed to be trying for a speed record. But he pushed his plane as fast as skill could push it. "Go!Go!" he growled.

Go it did. When Walker bumped to a 200-m.p.h. landing on the sun-hardened mud of California's Rogers Dry Lake ten minutes later, a check of his instruments showed that at his peak speed, just as his last ounce of fuel burned away, he had hit better than 2,150 m.p.h., faster than any man in history had ever flown before.