You’ve all seen the iconic photo of the American astronaut gracefully riding on his NASA-built MODOK chair. This astronaut was Bruce McCandless II, the communicator of the Houston capsule during the moon landing mission, Challenger crew member, and the driving force behind America’s ability to conduct operations outside the stifling confines of space shuttles and international stations. Without McCandless, there is no guarantee that the United States would have EVA capabilities today. Wonders all around, comprehensively researched and written by McCandless’s son Bruce III, explores the trials and tribulations of McCandless the elder during NASA’s formative years and his laser objective of allowing astronauts to traverse space without being encumbered by the mass of their ships.
Copyright @ 20201 Bruce McCandless III. Published by Greenleaf Book Group Press. Distributed by Greenleaf Book Group. Design and composition by Greenleaf Book Group and Kimberly Lance. Cover design by Greenleaf Book Group, Shaun Venish and Kimberly Lance. Cover image courtesy of NASA, photographed by Robert L. “Hoot” Gibson
During his long, leaden days waiting for space flight, my father found the path to redemption on the back of an aging cartoon character. From the afternoon of December 1966 when he first tried out the maneuver unit maneuvered in a Martin Marietta simulator, he became addicted to the sight of a gas-powered jetpack that would allow astronauts to operate. outside of their spaceship. This vision had an obvious antecedent in pop culture. In the 1920s, a comic book character named Buck Rogers – a rock-jawed American World War I veteran – succumbed to the effects of a mysterious gas he encountered while working as a land inspector. mines. He fell into a deep sleep and woke up after five centuries of slumber in a strange new world of spaceships, ray cannons and Asian lords. Although he initially traveled this new world via an anti-gravity belt, a device that allowed him and his best daughter, Wilma, to jump great distances at once, Buck eventually acquired a svelte and obviously omnidirectional. He eventually ventured into space on an adventure called The tiger men of Mars, and his exploits in the cosmos forever changed America’s vision for the future. Millions of people have followed Buck’s adventures in funny movies, on the radio, and in movie serials. Some of Buck’s imitators and spiritual heirs include Flash Gordon, Brick Bradford, John Carter of Mars, and Han Solo.
A host of talented men and women spent a lot of time and money to get this jetpack out of the fun papers and into the space shuttle. None worked harder, however, than Bruce McCandless and his main associate, an Auburn-trained engineer and Air Force officer named Charles Edward (“Ed”) Whitsett, Jr. Whitsett was a pale, bespectacled individual. , with gentle but tenacious manners. He was one step ahead of my father. He had been thinking and writing about jetpack technology as early as 1962. In a sense, he was trying to solve a problem that did not yet exist: namely, how could an astronaut venture out of his spaceship and perform constructive tasks in an oxygen-free environment, with extreme temperature fluctuations, and in an orbital “free fall” that would leave the space traveler basking in the practical equivalent of weightlessness? Alexei Leonov of the Soviet Union and American Ed White had proven that extravehicular activity was possible, that men could survive outside of their space capsule, but basically all they did was float. How could a man move from one part of a spacecraft to another, or from one spacecraft to another, or from a spacecraft to a satellite, in order to perform inspections or surveys? repairs? Neither need really existed in the early sixties, when the two nations’ programs were still trying to fire cans into low earth orbit and predict, more or less, where they would descend. But it is clear that the needs would eventually arise, and various methods have been proposed to meet them.
In the mid-1960s, the Air Force assigned Whitsett to NASA to oversee the development of the Air Force’s astronaut maneuver unit. The failure of Gene Cernan’s AMU test flight on Gemini 9 in 1966 – the “hell spacewalk,” as Cernan called it – set the jetpack project back on track, but it never disappeared. McCandless, Whitsett, and a NASA engineer named Dave Schultz worked quietly but diligently to keep the dream alive. They enlarged and improved AMU throughout the second half of the decade and into the 1970s. In the story of the “Forgotten Astronauts” thread which portrayed him as short of breath in 1973, my father mentioned why he wanted to stay in the manned space program despite not winning a mission to crew on Apollo or Skylab. “McCandless,” the article said, “helped develop the experimental maneuver unit M509. Skylab astronauts strap it on like a backpack and propel themselves Buck Rogers – just like inside the Skylab. [He] wants to build a larger operational unit to perform space tasks outside of the shuttle. And that’s exactly what he did.
Although the Skylab M509 tests in 1973 and 1974 were a resounding success, resulting in the triumph of the jetpack concept over rocket boots and the portable maneuver unit, Whitsett and McCandless did not rest on their laurels. Over the next several years, using the time and funding they could muster, the team made several upgrades – eleven, by a leader – to what was now called the “maneuvered maneuver unit.” or MMU. The ASMU’s bulbous nitrogen-gas fuel tank has been replaced with two profiled aluminum tanks at the rear of the unit, each wrapped in Kevlar. The number of propulsion nozzles has been increased from fourteen to twenty-four, positioned around the jetpack to allow precision maneuvers at six degrees of freedom. Smaller gyroscopes replaced those used on the ASMU and, as space historian Andrew Chaikin noted, the “manual pistol-grip controllers of the ASMU, which were tiresome to use in gloves. pressurized spacesuit, were replaced with small T-handles that only required a nudge with your fingertips. The new MMU arm units were designed to be adjustable, to accommodate astronauts of all sizes. Painted white for maximum reflectivity, the unit was designed to survive the 500 degree fluctuation in temperatures (from a high of 250 degrees F to a low of minus 250 F!) That an astronaut might encounter in the ‘space.
In 1980, the machine weighed 326 pounds. Like the AMU and ASMU before it, the MMU was designed to fit or “on” the astronaut’s pressurized suit. The shuttle astronauts wore a newly designed suit called the Extravehicular Maneuver Unit, or EMU, a marvel of textile engineering made up of fourteen layers of ripstop nylon, Gore-Tex, Kevlar, Mylar, and other substances. Power for the jetpack electronics was provided by two 16.8 volt silver-zinc batteries. Two motion control handles – the manual travel control and the manual rotary control – were mounted on the left and right armrests of the unit, respectively, and a button activated an “attitude hold mode”, which used gyroscopes. with motion detection to direct the shot. thrusters to maintain an astronaut’s position in space.
The machine had been tested in every way its designers could imagine. A representative from a local gun club visited Martin Marietta and shot the MMU’s nitrogen tank with a .50 caliber bullet to determine if the tank would explode if punctured. (It doesn’t.) The jetpack has undergone hundreds of hours of simulations. At my father’s request, a talented and intense project manager from Martin Marietta named Bill Bollendonk subjected the device to space-like conditions in the company’s thermal vacuum facility. MMU was no longer a “distant” experience, as Mike Collins once called it. It was now a promising space tool. Unfortunately, at the moment, it was still an unused space tool. American astronauts stayed on Earth, as NASA struggled to produce its next-generation orbital workhorse, the space shuttle.
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