Take a moment and imagine an astronaut riding a motorcycle on the moon. Congrats! You will never imagine anything cooler in your entire life. What’s surprising is this nearly became a reality.
I was alerted of the existence of the “lunar motorbike” yesterday by one of Jalopnik’s specially-trained carrier pigeons with a printed out copy of this tweet tied to its leg:
— Silodrome® (@Silodrome) March 22, 2017
Neither I nor fellow Spacelopnik correspondent Jason Torchinsky had ever seen this thing before, and I quickly set myself on finding an official government record of its existence.
I was unable to find one.
That is not to say there is no information on this vehicle. A number of secondary sources discuss its existence. The most trustworthy is likely the book Apollo: The Lost and Forgotten Missions, linked out by this NASA Spaceflight forum back in 2014. The book gives the following brief account:
Various modes of transporting astronauts across the lunar surface were evaluated for the Apollo programme. Here a suited engineer evaluates a lunar motorbike in Building 29 at MSC. He is attached to a hardness device that removes 5/6 of his Earth weight and that of the bike, allowing an accurate 1/6-g evaluation of the device. Other tests were performed in flying the KC-135 aircraft in parabolic curves to reproduce a 1/6 gravity environment in short 20-30-second bursts.
The lunar bike was not alone as a never-made-it mode of lunar transportation. We had a couple different vehicle proposals that got scrapped, including a fully-sealed and large-scale MOLAB that NASA actually favored back in 1963.
What got the lunar motorbike was that we never really needed it, as AmericaSpace explained in 2012:
It turns out that NASA did briefly consider sending its astronauts to the Moon with bicycles, electric mini-bikes to be exact. Information on these one-man vehicles is scarce, but a prototype was under development in 1969 for use on Apollo 15. It was a backup method in case the Lunar Roving Vehicle, the LRV colloquially known as the Moon Buggy, wasn’t ready in time for the mission’s launch. There was some talk about the mini bikes incorporated into later Apollo missions as well. But the LRV was ready and made its lunar debut carrying Dave Scott and Jim Irwin around the Hadley-Apennine region in 1971 and the last Apollo missions were cancelled. The closest the mini-bike ever got to space was prototype tests in a 1/6th gravity environment in 1969 in NASA’s Vomit Comet.
NASA did do a few different iterations of the design in testing, as RevZilla discovered a couple weeks back. They, too, had trouble tracking down official info on the bike, even contacting the National Air & Space Museum, whose Apollo archivist had never heard of the thing.
Ultimately, RevZilla managed to find the bike’s technical details discussed in a ‘72 issue of American Motorcycle Association News, and got in touch with “someone at MIT who was familiar with the project” who explained that not only did the Lunar Rover make the bike obsolete, but the bike had a hard time pulling “the rickshaw,” NASA’s two-wheeled trailer for carrying scientific equipment on the moon. NASA first went out and just bought a then-new Honda CT90 dirt bike, seen with a very cautious-looking rider.
NASA then built its own minibike with a mockup electric drivetrain seen in the top photo taking a jump (!) in the vomit comet. Finally, NASA did make a full electric lunar minibike with a 5/8ths horsepower motor and a 30 amp-hour battery, presumably using the same non-rechargable silver-zinc potassium tech that Boeing and GM developed for the Lunar Rover, as RevZilla hypothesized.
Of interest is that NASA tried out a beeswax cooling system on the bike, which is just about the most jarring intersection of hippy-dippy low tech thinking with high-tech application. Without any atmosphere on the moon to absorb the heat of the lunar motorbike’s motor, NASA engineers built the pieces of the bike’s frame as its cooling jacket, filled with beeswax that would melt and absorb heat. Once the wax got too hot, astronauts would just stop and wait for the wax to re-harden and set off again.
Oddly, the bike did not use airless tweels like the Lunar Rover did, as NASA’s engineers didn’t think they were necessary. Astronauts’ suits inflated to the point of feeling hard, so NASA assumed there was a way to get rubber tires to do the same with the right pressure.
How far NASA got with this bike, however, isn’t totally clear, as RevZilla noted:
(I sent the photos accompanying this story to Lennon Rodgers, a friend of mine who once built a bike to race in the Isle of Man TT Zero event, and who previously worked for the Jet Propulsion Laboratory. He immediately noticed that the bike in the photos doesn’t have a battery pack big enough for the mission. He suspected it was just an early proof-of-concept that they built to see whether an astronaut could control it at all at one-sixth g.)
So the bike was sort of a backup plan that never materialized and never really needed to.
Our space program now seems relatively straightforward. We built our rockets, we did our math and we made it steadily higher and higher up until we landed on the moon. But the lunar motorbike is a reminder that there were many dead-ends along the way. And it makes me wonder if there are yet still other ways of getting people up and around in space that we haven’t tried out yet.