The concept of space travel was so new to us that when President Kennedy gave his famous lunar speech, even NASA’s top scientists weren’t entirely sure if we could really land on the lunar surface. Some thought that any craft that landed there would simply sink into the moon’s regolith as if it were a massive, airless pit of quicksand! In his latest book, Across the wireless wilderness: A lunar rover and the triumph of the final landing on the moon, a journalist and former Fulbright colleague, Earl Swift, examines the often-ignored Apollo 15, 16 and 17 missions, our last trips to the lunar surface (at least until the Artemis project takes place). In the paragraph below, Swift takes the reader on a tour of JPL’s hyper-rigorous tread shredding course and the rover dominance battle fought there between GM and Bendix.
From the book OVER THE AIRLESS GAME: A lunar rover and the triumph of the final landing on the moon – Earl Swift. Copyright © 2021 by Earl Swift. From Custom House, a series of books by publisher William Morrow / HarperCollins. Reprinted with permission.
Until 1962 and 1963, both GM and Bendix oversaw the Surveyor program. Certainly, this coming summer, the Jet Propulsion Laboratory set its requirements for a hundred-pound remote-controlled rover that wanted to board ships. The vehicle would explore the lurenica up to a mile from the surveyor, while drivers on Earth would operate it with television eyes. The lab has warned companies planning to bid for a Phase 1 design study – the normal first phase of any new hardware program – that they will be expected to offer engineering models of their concepts. Proposals were due in seven weeks.
The short deadline has eradicated dilettantes. In October, the two remaining companies – GM and Bendix – began contract work. GM was ready with its six-wheel drive design. His lunar rover Surveyor weighed six feet on eighteen-inch wheels and weighed ninety pounds — half as much and half as heavy as his test bed, with a sure foot that fell no less. On Pavlić’s “lunar” of rocks, craters and slopes outside the Santa Barbara laboratory, he climbed forty-five degrees, jumped over twenty-inch cracks and bent over the steps and over thirty centimeters.
Becker and Pavlics had been working on the idea for more than three years. Their main progress this time: wheels. Again they were made of wire, but it was woven into a wide net resembling a chain and shaped into greasy donuts. Like the team’s earlier wire tires, they swerved when they hit an obstacle and soaked up some bumps in the terrain. They worked with or without a fabric cover.
“We had a big program to try to come up with a wire material that would survive the vacuum environment on the moon,” John Calandro recalled. “Frank designed a testing device that created the vacuum environment we needed.”
If fully prepared for the mission, the rover would be an electronic marvel, with subsystems supplied by RCA Astro-Electronics and AC Electronics, GM’s Milwaukee division: it would have a stereo TV recorder, sophisticated navigation and control, and a silver zinc batteries charged with a solar panel. But part of Santa Barbara’s job, just the vehicle, was to study doing more with less. The hardware was constantly “assessing whether something simpler could do the same job,” designer Norman J. James would recall. “‘The part that stops is never interrupted’ was a oft-repeated phrase.”
Bendix took a radically different approach. His SLRV was a rotten, two-piece, articulated robot, with curved legs that absorbed bumps at the corners and ended up in small caterpillar assemblies. The paths lined up independently to follow the uneven ground. The executives operated it with commands to slow down, accelerate, or turn the tracks on one side or the other, and the rest consisted of a pivot connecting the two halves. On the moon, it would be powered by a radioisotope heat generator – a small nuclear device – that hangs from the back and bristles with scientific instruments and antennas. She weighed a hundred pounds.
Side by side with the GM model, the Bendix machine looked bulky and awkward, and those little caterpillars didn’t look exactly like they matched the almost spherical wire wheels of the Pavlics. But Bendix was in a design mood until May 1964, when a panel of U.S. Geological Survey Caltech and NASA took two models to a volcanic field north of Flagstaff, Arizona, and released them on a robust Bonito. Lava Flow. “We had one little section where they could really get into some pretty rough stuff,” Jack McCauley of the Geological Survey recalled years later. “The GM vehicle was perfect. He came from point A to point B without any accidents or reversals.
“The poor Bendix vehicle had tread layers like tanks made of some kind of rubber,” McCauley said. “The vehicle has just started to crush the tread parts. In fact, when they finished halfway down, there were no more treads left. So the GM thing obviously got our blessing. “
General Motors achieved a decisive victory. Unfortunately, that didn’t increase on the rover on the moon. “Rover Boys”, as the saw blade became known, were impressed by the hexagon, but its capabilities did not match the requirements of the Jet Propulsion Laboratory: namely, “go around and take pictures every ten meters, and also use a penetrometer to see how much is the power of the lunar soil – and that it is done in a predetermined way, ”McCauley said. “Basically, just make a survey network.” Bendix produced too few rovers for the mission; GM has produced too much. The Rover Boys reluctantly reported that no rover met the stated needs of the Surveyor program, and that was one of the reasons NASA cleaned up the rover component shortly thereafter.
At that time, JPL’s Ranger program finally gave NASA a first close-up view of the Moon. Their design was a brief insight: Ranger probes crashed to the surface of the moon as they took high-resolution photos until the moment of impact. Conceived in 1959, the program sometimes seemed like another frustrating exercise. After Rangers 1 and 2 made two development test trips in 1961, Rangers 3 through 6 came along, all of which were doomed. It wasn’t until July 1964, and Ranger 7, that the program literally hit the dirt. As the spacecraft fell toward the moon, the cameras launched and, for some seventeen minutes, took and transmitted photographs of the approaching surface – a total of 4,316 images, some of them at a resolution hundreds of times higher than the best taken from Earth. The photographs did not allay fears inspired by the writings and lectures of Thomas Gold, but found that Maria was smooth enough to land.
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