Telemetry on the ground showed the altitude dropping ... 1,600 feet ... 1,400 ... 1,000. The beleaguered computer flashed another warning. The two men far away said nothing.

Not till Eagle reached 750 feet did Aldrin speak again. And now it was a terse litany: "750 [altitude], coming down at 23 [feet per second, or about 16 miles an hour]... 600 feet, down at 19... 540 feet, down at 15 ... 400 feet, down at 9 ... 8 [feet per second] forward ... 330, 31/2 down." Eagle was braking its fall, as it should, and nosing slowly forward.

But now the men in the control room in Houston realized that something was wrong. Eagle had almost stopped dropping, but suddenly-between 300 and 200 feet altitudeits forward speed shot up to 80 feet a second -about 55 miles an hour! This was strictly not according to plan.

At last forward speed slackened again and downward velocity picked up slightly.

"Down at 2 1/2 [feet per second], 19 forward ... 3 1/2 down, 220 feet [altitude] ... 11 forward, coming down nicely, 200 feet, 4 1/2 down ... 160, 6 1/2 down ... 9 forward ... 100 feet."

And then, abruptly, a red light flashed on Eagle('s instrument panel, and a warning came on in Mission Control. To the worried flight controllers the meaning was clear. Only 5 percent of Eagle's descent fuel remained. By mission rules, Eagle must be on the surface within 94 seconds or the crew must abort give up the attempt to land on the moon. They would have to fire the descent engine full throttle and then ignite the ascent engine to get back into lunar orbit for a rendezvous with Columbia, the mother ship.

When only 60 seconds remained, the countdown began. The quivering second hands on stopwatches began the single sweep that would spell success or failure.

"Sixty seconds," called Astronaut Charles Duke, the capsule communicator (CapCom) in Houston. Sixty seconds to go. Every man in the control center held his breath.