Space: Sad End for a Surveyor

The fabulous achievement of Sur veyor 1, which sent back more than 11,000 pictures from the surface of the moon, was a tough act to follow. In a disappointing performance last week, Surveyor 2 did not even come close.

Uncontrollable and lifeless, it plowed into the moon’s Seething Bay at 6,000 m.p.h. and was completely demolished in the crash.

It was a sad ending for a flight that had made an impressive start. Launched by an Atlas Centaur rocket less than a second before its time “window” closed, Surveyor headed toward the moon on a near-perfect trajectory that would have set it down just 40 miles from its intended target in Central Bay. Their hopes buoyed, scientists at Pasadena’s Jet Propulsion Laboratory planned a minor mid-course correction and ordered Surveyor’s three small vernier engines to fire briefly. Two of the engines performed obediently, but the third refused to work. The resulting unbalanced thrust threw Surveyor into a tumble that built up to 146 revolutions per minute after repeated but vain attempts to fire the balky engine. As the ship’s solar panels whirled wildly, they were unable to fix on the sun and generate electricity, and the spacecraft’s batteries began to fail.

Aware that Surveyor was dying in space, scientists decided to salvage some engineering telemetry data from the mission. They turned on the craft’s landing radar system to check the effect of failing batteries on its operation, then they opened the vents on the liquid helium tanks to test the system that pressurizes Surveyor’s rocket fuel. In a last effort, they fired the spacecraft’s big retrorocket while it was still 70,000 miles from the moon. The spin rate slowed, but not nearly enough. Then, while the retrorocket was firing, all contact was lost with the ill-fated lunar voyager.