I was 13 years old in 1984, the Cold War was still years away from thawing, Reagan’s Strategic Defense Initiative had been announced the year before, and Space Shuttle Challenger is launched on the 10th Space Shuttle mission.  During that mission, a lone astronaut drifts in the freezing cold of space 217 miles above Earth using a nitrogen propelled jet pack. That’s Bruce McCandless, floating free in the blackness of space on the first untethered spacewalk from the relatively safety of his spacecraft. Today I’m meeting astronaut Bruce McCandless who reminds us that we are all astronauts of Spaceship Earth.

Bruce McCandless joined NASA in 1966 and was CapCom on Apollo 11 during the first moonwalk. He was later assigned to Skylab and worked on developing the Manned Maneuvering Unit (MMU), something he would later test as Mission Specialist on Space Shuttle Challenger on STS-41B leading to that famous image. His last flight was on board Space Shuttle Discovery STS-31 to deploy the Hubble Space Telescope.

Bruce McCandless

The presentation by Bruce McCandless was organised by the superb team at Space Lectures:

When I was growing up we didn’t have a space program as such in those days, we had comic strips and artistic works depicting fanciable space ports on Mars for inspiration. The family wisdom, if I ever talked about space, was that yes, man would go into space some day, but certainly not before the year 2000. With that I proceeded to college at the United States Naval Academy and was fascinated by submarines, particularly nuclear submarines and was looking at that for a career choice.

Then in 1957, my senior year, the Soviet Union unexpectedly launched a small satellite, Sputnik. The message that it carried was that the space age was upon us and that things were going to happen very rapidly. I changed my mind on my career, took the flight physical exam, got into aviation, became a navy fighter pilot flying off of aircraft carriers and was then sent by the navy to Sandford University where one afternoon, a very grand looking letter arrived saying that I met the basic requirements for the astronaut programme at NASA.

Everybody said that if I applied now I’d never be selected the first time around. So I applied and did get selected and joined the astronaut programme in June 1966. This was just a year after Ed White’s spacewalk. I would point out that Alexi Leonov of the Soviet Union was the first to do a spacewalk, lasting 12 minutes. The US of course had to do better than that, so Ed White stayed out for 23 minutes and made it look easy.

The next time the US attempted a spacewalk was with an air force built astronaut maneuvering unit that Gene Cernan attempted to fly, but the pressure suit technology over heated, the visor fogged up and we nearly lost Gene Cernan. Maneuvering Units acquired a bad name, undeservedly, so I collaborated on trying to rehabilitate the concept of flying around a spacecraft.

We did this by experiment M509, it was intended and did fly inside the Skylab workshop. the case study verse reality was somewhat different. It did fly beautifully inside the workshop. We stayed inside because that allowed us to operate without undue concerns for safety, we were contained inside the workshop. My compatriots worked satisfactory and we used their testimonies to develop a unit for flight with the space shuttle.

Alan Bean flies the M509 Astronaut Maneuvering Equipment on Skylab

In training for spaceflight, there’s no one perfect simulator. It’s a part test, pick up some information, do little more and pick up more information till you finally get into space where you integrate it all mentally. We had a simulator underwater that was a mock-up showing how you could get in and out of the docking station in a weightless environment. There was  much better simulator which was like a cherry picker that had a set of carriages and rails so you could move up and down, left and right, inside a room roughly 20 metres long and 6 metres high and wide.

This was very effective, the controls on the MMU were linked to a computer in the basement which would then make you behave as though you were flying in space. I got about 300 hours over the years flying this thing. The actual requirement for later crews was about 15 hours, I guess I was over trained.

The Untethered Spacewalk

Finally in February of 1984, a crew of 5 of us launched, we had a little trouble getting used to zero gravity. The Commander was Vance Brand, Hoot Gibson took the still photo that became famous, Ron McNair, myself and who was my partner in the spacewalk. The MMU turned out to be sufficiently difficult to get of out of the airlock hatch so we mounted it in the payload bay, got into it and flew off.

Finally the opportunity came to go flying. Looking back as I got further and further away, the Shuttle got to be tinier and tinier. I had planned on stopping at the greatest distance, I was supposed to go out 100 yards and stop. I wanted to turn around 180 degrees and contemplate the vastness of space and the Earth but somehow the conversations were just so busy, I forgot about it till I got back in.

But it is a true statement that sound does travel through a vacuum but radio waves do. I had 3 different people talking to me. Mission Control wanted to know how much oxygen I had left and how the battery was doing, what was the temperature. Commander Vance Brand wanted me to stay away from the engines and not go under the wing, stay where he could see me and Bob Stewart wanted to know when was his turn to fly.

Bruce McCandless, Astronaut, Spacewalker

It was pretty noisy out there. The system worked quite well and looking from the shuttle out, I got to be pretty small at 100 yards away, and Hoot took what has become an iconic photo, almost symbolic of the space age. you can see the nose of the shuttle in the reflection in my visor and by extension, the other 3 crew members. You have to remember that we had a very large team in NASA, around 500 people, and within he contracting facility, several thousand people working together in coordination, had other mission objectives on the flight, in addition to the Manned Maneuvering Unit (MMU), but it was a team effort.

When I got away from the shuttle, I got very cold. My teeth were chattering, I was shivering. the problem was that the life support system, in reaction to people like Gene Cernan overheating during Gemini was engineered to keep a person who was working in a warm environment comfortable. When you get away from the shuttle, you are radiating more to space, and quite honestly, flying the MMU was an exercise in using your fingers. We had the control set up to put little pulses in, it wasn’t metabolic work so I got rather chilly. Fortunately it turned out that we could in fact shut down the entire cooling system of the life support system, warm up and then turn it back on.

One of the things that everybody who has gone into space, is the impact of looking down at the Earth. You start off trying to find your town, your launch facility and you realise that you really need to appreciate the continents, the land mass and that very few political division are visible from space, we’re all in this together, and that we have to work together.

This leads me to the concept of spaceship Earth. I have been introduced as the astronaut, but I submit that everyone in this room is an astronaut in the sense of being a crew member from spaceship Earth. Its a very big spaceship, nut its not infinite and it has systems, open and close valves to produce electricity, ocean currents, atmospheric circulation, concerns about pollution, ozone depletion, and somehow, if we are going to pass on a better spacecraft to our children of the next generation, we need to manage the systems in their best interest.

Bruce McCandless


Questions from the audience

  • To become an astronaut is a major achievement in itself, but could you tell us about becoming a naval aviator and in particularly how did you learn to land an aircraft on the deck of an aircraft carrier in rough seas, did you have any mishaps.

First I would like to give credit to the Royal Navy, they came up with the angled deck and for the mirror landing system. the original aircraft carrier configuration was a straight deck, the length of the ship, and when it came to land, you had to try and grab one of the spiders wires originally, if you missed, you had to park the aircraft at the front of the ship, or had a nylon web barricade that you ran into to stop you. the other feature was that we originally had Landing Signal Officer giving you advice on how to properly position yourself. That was very subjective.

The Royal navy came up with a mirror system, a light was reflected in a mirror with reference to a string of green horizontal lights that worked very effectively. With those two things I basically went though flight training and then practices with an instructor in the back seat till we made landings. I have to say in all honesty the most stressful moments in my career were making night carrier landings in bad weather with low fuel, it really gets your attention. Having said that within NASA we always had Mission Control to fall back on. Within the NASA environment, we had a much better management of the stress levels.


  • Could you tell us about your time as CapCom on the first moon landing, could you tell us what that was like.

First off in preparation for being CapCom, you trained with the crew ahead of time and the idea of being CapCom was the communication link to speak the same language as the crew in order to facilitate priority and understanding. In the case of the landing, Charlie Duke was CapCom for the actual landing and I standing in as a spectator behind him to make sure what the situation was and immediately after landing have a procedure for staying 5 minutes, check all your systems and safe to disarm the lunar module and stay for a while. After that I went home to get dinner because the flight planned for Armstrong and Aldrin to take a 2 hour nap to be refreshed for the spacewalk.

By the time I got home, which was a 15 minute drive, my then wife was running down the driveway, telling me to go back because they cant sleep. i turned around and drove back, the moon was about 30 degrees up in the sky, it didn’t look a bit different but I knew my friends were up there. We did go out 2 hours early, this meant the antennae at Goldstone couldn’t pick up the television signal, Honeysuckle Creek in Australia jumped into the breach and relayed the video to Houston. Everything went reasonable well for 4 or 5 minutes and then I hear this voice say “This is the Whitehouse communications room, President Nixon would like to talk to Buzz and Neil.” We never simulated that, we simulated all sort of failures and scenarios but never stiff-arming the President. It was contingency standard, get a rock, any rock and put it in your pocket, if you have to get out of there in a hurry, you’ve got at least one rock.

Apollo 11


  • Are you able to repeat your famous words as Neil Armstrong came down the ladder.

Let me comment that my job was not to talk much, to try and and get Neil and Buzz to talk because they were the people on the moon. My job turned out to be making sure they didn’t miss anything, make sure they stayed moire or less on the timeline and keep quiet.


  • There was a long gap between your selection and your first flight, how did you maintain your motivation all that time?

You don’t just sit around waiting for a flight. In the case of the Apollo mission I trained for Apollo flights, I was the youngest guy in the group, I was back up crew for one of the Skylab missions and then 2 assignments on the shuttle programme. In the mean time you are helping out with development activities at the contractors, training at research facilities.


  • You said night landings on the aircraft carrier caught your attention, I assume when you left the confines shuttle bay on the untethered spacewalk, that caught your attention as well. Once you left the spacecraft and got so far out, was there a rescue plan if you forgot to turn round and come back.

The Manned Maneuvering Unit (MMU) itself was totally redundant, it had two of everything, two sets of contacts for every switch, thrusters, batteries. Any single failure could be isolated and could keep on flying. if both systems had simultaneous failures, you could disable both and wait for the shuttle to fly in and get you. These days on the ISS you do have a miniaturised version of the MMU being used as a life jacket, a self rescue device. The ISS cannot chase you through the sky so you have to be able to tether yourself back. I felt very comfortable and we concluded that using a tether would be more hazardous.

Bruce McCandless modelling the MMU


  • In your opinion is to more important to focus on sending human beings back to the moon again or further development with the ISS?

I don’t think its an either or situation. We have the ISS in an operational mode, the annual expense of operating it is to get even less, we should operate it for as long as is reasonably feasible. There will come a time when systems start failing irreparably. If humans went back to the moon is something that we could do in parallel and try to do on a multi-national, cooperative collaborative basis.

Unfortunately former President Obama, with respect to the moon, said, been there, done that. A very short sighted opinion, we have not been to the back side of the moon and is very different from the front side. The back side continues to take meteor impacts and pock marked with craters. The front side is relatively smooth, we have not been to the poles where there may be water ice, we have not landed in the rough areas of the front surface, we picked out the smooth spots for safety. There is a lot we don’t understand yet.


  • You did so many hours of training for the MMU, how did the training compare with the reality? We know that plans are useless but planning is essential, would love to compare the training against the actuality.

I did about 300 hours on the simulator, the simulator was very good. The only discrepancy was an attitude hold feature and trying to accelerate, with a noise best described as chatter. The explanation for that was that my centre of mass was slightly displaced from the geometric centre of the thrusters. When I tried to accelerate, there was a little twitchy moment and the automatic attitude hold would marginally hold the thrusters.  The simulator had been performing properly, its just that it didn’t make any noise, we couldn’t feel it.

The more realistic question, on STS-51-A, Dale Gardner was not a pilot, had never flown an airplane, had 15 hours of training in the simulator and very successfully retrieved a satellite. We thought 15 hours was a reasonable amount, the bulk of my time was done in development testing. The simulator also allowed operators to introduce more than 100 failures to give a challenge in figuring out what a problem was, isolate the system and overcome it.

MMU development at the Martin Marietta plant in Denver, Colorado


  • On the second shuttle mission for the Hubble deployment, how evident was the extra altitude compared to normal shuttle missions in low Earth orbit?

As I recall we got to 336 nautical miles, we used 49% of our own propellant getting up there, we used 50% to come down for de-orbit and reentry and 1% left over. That altitude allowed the Hubble to go for a significant amount of time before a re-boost but also put us going through the Van Allen radiation belts in the South Atlantic Anomaly. When it came to going to sleep, there were little puffs of light, like cotton balls lighting u. These were charged particles stimulating or destroying cells in the retina of your eye. It was interesting from an abstract point, a bit disconcerting from the possibility of degrading your vision. We were only up on that mission for 5 days, we were unhappy about having to come back so soon.


  • Did you have any concerns or nerves about not having a tether?

Yes I did, NASA did spend 3 million dollars on developing what amounts to a giant fishing reel.When we stopped to consider the situation, if you have this cord totally limp, it was likely to tangle around something, a crewman’s foot, high gain antenna. if you had a small amount of tension on it, it was going to your motion and drag you back in. We felt it was more of a risk than making sure we had a reliable system. We built every conceivable test we could think of, including being in a vacuum chamber and the freezing cold.


Bruce McCandless and Nick Cook

Another great event from the team at Space Lectures, a great photo from Proffoto, and of course, a signed picture of one of the most iconic space images.



Space Lectures


My other astronaut visits:

Meeting the Moonwalker Charlie Duke from Apollo 16

Meeting Mike Foale from the Mir Space Station collision

Meeting Tom Cruise’s Middle Finger & Top Gun Shuttle Astronaut Scott Altman

The Twins Paradox – Meeting the twin Astronauts Mark and Scott Kelly

Gemini and Apollo 10 Astronaut Tom Stafford

Apollo 8, Apollo 13 and Gemini Astronaut Jim Lovell

Apollo 7 Astronaut Walt Cunningham

Space Shuttle Astronaut Eileen Collins

Meeting Fred Haise from Apollo 13

Meeting Astronaut Ken Mattingly of Apollo 13 and Apollo 16

Meeting the Moonwalker Alan Bean from Apollo 12

Meeting Apollo, Skylab and Shuttle astronauts at CosmicCon


Nick Cook. Amateur astronomer, space, history, nerd, extreme dog walker, cat slave, severe tinnitus sufferer. 13.7 billion years in the making - not that much better for it.

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