You’ve all seen the iconic image of an American astronaut riding gracefully on his MODOK chair built by NASA. That astronaut was Bruce McCandless II, a communicator in a Houston capsule during a lunar landing mission, Challenger a crew member and the driving force behind America’s ability to conduct operations beyond the suffocating borders of spacecraft and international stations. Without McCandless, there is no guarantee that the United States will have EVA capabilities today. Wonders All Around, which was extensively researched and written by McCandless’ son, Bruce III, explores McCandless’ s older trials and tribulations during the years of NASA ‘s formation and its laser focus on allowing astronauts to pass through space unencumbered 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, taken by Robert L. “Hoot” Gibson
In his long leaden days of waiting for a space flight, my dad found a way to redeem himself on the back of an elderly cartoon character. Since the afternoon of December 1966, when he first tested the Maneuvering Unit with a crew on a Martin Marietta simulator, he has been drawn to the vision of a gas-powered backpack that would allow astronauts to work outside their spacecraft. This vision had an obvious precursor to pop culture. In the 1920s, a comic book character named Buck Rogers – an all-American World War I veteran with a jaw stone – succumbed to the mysterious gas he encountered while working as a mine inspector. He fell asleep and after five centuries of sleep woke up to a strange new world of spaceships, air cannons and Asian supremacists. Although he initially traveled this new world using an anti-gravity belt, a device that allowed him and his best girlfriend, Wilma, to jump long distances at once, Buck eventually acquired a thin and apparently omnidirectional jet pack. Eventually he ventured into space into an adventure called Tiger humans from Mars, and his exploits in space forever changed the American vision of the future. Millions followed Buck’s adventures with laughter, on the radio and in movie series. Among Buck’s imitators and spiritual successors are Flash Gordon, Brick Bradford, John Carter of Mars and Han Solo.
Many talented men and women have spent a significant amount of time and money to pull that jet pack out of the funny newspapers and into the space shuttle. However, no one worked harder than Bruce McCandless and his chief associate, an Auburn-educated engineer and aviation officer named Charles Edward (“Ed”) Whitsett, Jr. Whitsett was a pale person in glasses, gentle but persistent. He had an advantage over my father. He thought and wrote about jetpack technology as early as 1962. In a sense, he was trying to solve a problem that did not yet exist: namely, how an astronaut could go beyond his spaceship and perform constructive tasks in an oxygen-free environment, with extreme temperature fluctuations and orbital ” a free fall ”that would leave the cosmic universe swaying in the practical equivalent of zero gravity? Alexei Leonov of the Soviet Union and American Ed White proved that activities outside the vehicle were possible, that humans could survive outside the space capsule, but they were basically just floating. How could man move from one part of a spaceship to another, or from one spacecraft to another spacecraft, or from a spacecraft to a satellite, to carry out inspections or repairs? None of these needs really existed in the early 1960s, when the programs of both nations were still just trying to fire cans into the Earth’s low orbit and predict, more or less, where they would return. But it is clear that needs will eventually arise, and different methods have been proposed to address them.
In the mid-1960s, the Air Force assigned Whitsett to NASA to oversee the development of the Air Force Astronaut Maneuvering Unit. The failed test flight of AMU Gene Cernan on Gemini 9 1966— the “space walk from hell,” as Cernan called it — brought the jetpack project back, but it never disappeared. McCandless, Whitsett, and a NASA engineer named Dave Schultz worked quietly but diligently to keep the dream alive. They expanded and improved AMU throughout the second half of the decade and into the 1970s. In a wire story about “Forgotten Astronauts” that portrayed him as a flush in 1973, my dad mentioned the reason he wanted to stay in the space program with the crew despite not winning the crew assignment at either Apollo or Skylab. “McCandless,” the article says, “helped develop the M509 experimental maneuver unit. Skylab’s astronauts tie it up like backpacks and launch Buck Rogers – like around Skylab’s interior. [He] wants to build a larger operational unit to perform space operations outside the shuttle. “And that’s exactly what he did.
Although tests of the Skylab M509 in 1973 and 1974 were a huge success, resulting in the triumph of the jetpack concept over rocket boots and a manual maneuvering unit, Whitsett and McCandless did not rest on their laurels. Over the next few years, using whatever time and resources they could muster, the team made multiple upgrades — eleven, one at a time — to what was now called a “manned maneuver unit,” or MMU. The ASMU nitrogen nitrogen and gas fuel tank was replaced with two aluminum tanks in the rear of the unit, each of which was wrapped in Kevlar. The number of drive nozzles has been increased from fourteen to twenty-four, placed around the pocket to allow precise maneuvering with six degrees of freedom. Smaller gyroscopes have replaced those used on ASMU, and, as space historian Andrew Chaikin noted, ASMU’s “handguns with a pistol grip, which were tired of working in space gloves under pressure, have been replaced by small T- handles that only required pushing fingertips. “The new MMU hand units are designed to be adjustable to accommodate astronauts of all sizes. Painted in white for maximum reflection, the unit is designed to survive temperature fluctuations of 500 degrees (from high 250 degrees F to low minus 250 degrees F) that an astronaut could encounter in space.
By 1980, the machine weighed 326 kilograms. Like the AMU and ASMU before it, the MMU is designed to fit an astronomical suit or “overturn” it. The shuttle astronauts wore a newly designed suit called the Extravehicular Maneuvering Unit, or EMU, a two-piece marvel of textile engineering made up of fourteen layers of nylon ripstop, Gore-Tex, Kevlar, Mylar and other substances. Powering the jetpack’s electronics was provided by two 16.8-volt silver-zinc batteries. Two motion control handles — a translational hand controller and a rotating hand controller — were mounted on the left and right armrests of the unit, and the button activated a “position holding mode,” which used motion sensitivity gyroscopes to direct thrust fire to maintain astronaut positions in space.
The machine was tested in every way its designers could have imagined. A representative of the local arms club visited Martin Marietta and fired an MMU nitrogen tank at a .50 caliber bullet to determine if the tank would explode if it broke through. (No.) Jetpack went through hundreds of hours of simulations. At his father’s urging, a talented and intense project manager Martin Marietta, named Bill Bollendonk, exposed the device to space-like conditions in the company’s thermal vacuum. The MMU was no longer a “distant” experiment, as Mike Collins once called it. It was now a promising space tool. Unfortunately, for now, it was still an unused space tool. American astronauts remained on Earth while NASA struggled to produce its next-generation orbital workhorse, the space shuttle.
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