The Ranger series of space probes finally succeeded — on the seventh try.
- By George C. Larson
- Air & Space magazine, January 2013
NASM / NASA
Anniversaries usually celebrate successes, but for a change of pace, we’ll celebrate a series of failures, which sometimes are better teachers.
The Ranger series of space probes, launched 51 years ago at what would seem to be a straightforward target—the moon—failed six times to perform their mission before finally succeeding on the seventh try. That record caught the attention of Congress, resulted in a sweeping reorganization of the newly created National Aeronautics and Space Administration, and reformed spacecraft design and preparation for flight.
The moon became an early target for space scientists doodling on their calendars because it was the closest and most obvious target as well as the simplest mission to another celestial body to achieve. But when President John F. Kennedy’s 1962 speech made a human landing on the moon before the decade’s end a national goal, the doodles got serious. For one thing, the problem of landing astronauts safely required a thorough scouring of the moon’s rugged surface to find a suitable spot. Earthbound telescopes took pretty pictures, but this would require a much closer look. And that meant a spacecraft.
It’s worth recalling that in the early days of the Space Age, Americans became inured to failure. In 1957, the Vanguard rocket that was intended to put the first U.S. satellite in orbit blew up on the pad while millions watched on television. News cameras perched across from Cape Canaveral filmed supposedly secret tests of rocket boosters, filling home TV screens with vehicles exploding like fireworks.
Ranger began in 1959, before Kennedy’s speech launched the Apollo program, as a way to catch up with the Soviets’ Luna probes; Luna 3 had already orbited the moon and photographed most of its surface. The Jet Propulsion Laboratory in Pasadena, California, had developed the Ranger spacecraft for NASA, and the program was repurposed for Apollo to find a landing zone and to achieve the seemingly simple goal of sending cameras moonward to transmit a lot of images, then hit the surface so a seismic sensor could measure the resiliency of the lunar crust. Ranger 1 established the basic spacecraft configuration: a pair of wing-like solar arrays, a high-gain dish antenna, and a tower holding scientific sensors and instruments.
The opening launch was an omen: The first countdown was delayed, then postponed. A leak stopped the second, and a bad valve aborted the third. On the fourth, the spacecraft, while still on the pad, began to unfold as it would have in orbit. Finally, on August 22, 1961, it was launched into a parking orbit. But its Agena engine failed to restart, and the satellite tumbled in low Earth orbit until on August 30 it burned up on reentry.
Ranger 2 suffered the same fate in November.
Ranger 3 missed the moon by more than 20,000 miles and is still in orbit around the sun.
Ranger 4 hit the far side of the moon in April 1962, but its solar panels had failed to deploy; unpowered, it delivered no images.
Ranger 5 had a power failure and joined Ranger 3 in orbit. A resulting NASA inquiry labeled JPL’s proving practices as “shoot and hope,” and the Ranger design was scrapped. Blame went to the practice of heating the probe to sterilize it; JPL’s management practices were roasted, personnel were fired, and procedures were overhauled.
Two years and many sleepless nights later, the new and improved Ranger 6 hit the moon but sent home zilch. After more investigations and management shakeups, on July 31, 1964, a redesigned television system aboard Ranger 7 delivered extremely expensive images. In the press room, the end of the mission was narrated thus: “One minute to impact…. Excellent…. Excellent…. Signals to the end…. IMPACT!”