Manned Maneuvering Unit Revisited

The 40th year anniversary features the same old tale.

Jun 13, 2024

All images in this article courtesy of NASA.

NASA gets away with a lot. Mainly due to a complaint, unquestioning science and technology media. If America’s premier space agency chooses to deceive the public they can. And do. I can tell from my own research experience that NASA documents often contradict their press releases and in turn, contradict the articles by science based journalists. It is as if these journalists are not reading the source documents. Actually, their articles often resemble PR releases for NASA.

It’s similar to when the Warren Commission released their report on the JFK assassination and later published a 26 volume set of collected hearings and evidence. There was some concern expressed about releasing all the data they had collected. Some Commission members such as former CIA director Allen Dulles thought the public would have little interest in reading any of it. Nobody anticipated the development of the internet. Years later when they were all scanned and placed online it became quite apparent that evidence in the 26 books contradicted various facts in the Warren Commission report.

In this instance, NASA’s 26 volumes are the files in the Technical Report Server. They portray a remarkably different narrative.

The 40th Anniversary

With 2024 being the 40th Anniversary since the roll out of the Manned Maneuvering Unit, MMU, it was a chance for NASA to show they were still capable of cutting edge technology.

As I have shown in an article and a video of mine, the MMU and the speed of the Space Shuttle in orbit are incompatible with each other. The MMU’s main speed is 45 mph, while the Shuttle in orbit is traveling at 17,500 mph. No astronaut in the MMU could have safely left the Shuttle and would be stranded in space.

It was a PR stunt. But the myth continues.

Notice how NASA will not state the mph but 66 feet a second is 45 mph.

The Smithsonian Magazine Adds To The Myth

The Smithsonian magazine website on May 8, 2024 posted an article, The Inside Story of the First Untethered Spacewalk by Adam Higginbotham, which is an excerpt from his book, Challenger: A True Story of Heroism and Disaster on the Edge of Space. What caught my eye was the writer stated that when Bruce McCandless left the Shuttle’s cargo bay with the MMU he was traveling in space at 23 times the speed of sound. Whoa! Since the speed of sound is 767 mph, 23 times would be 17,641 mph. Think about it—how can nitrogen thrusters accelerate from 0 to 17,641 in just a few seconds? That is faster than the Shuttle in orbit! What would the G forces on an astronaut do?

What Higginbotham proposes here is impossible to the point of being absurd. From NASA’s own documents, the MMU can only produce 33.6 lbs of thrust on the low end and 134.4 lbs at the high end being issued from a set of 24 nitrogen thrusters. Hardly enough thrust to generate this massive velocity.

NASA: Manned Maneuvering Unit User’s Guide

One can easily download the manual to the MMU and read the facts regarding this device and how it couldn’t have been of practical use. No wonder NASA only used it for three missions and moved on.

I don’t know where Higginbotham got this from but it wasn’t sourced from any NASA document I’ve seen. His writing style is called narrative nonfiction. Perhaps a little too much narrative and not enough nonfiction.

(Ironically, Smithsonian Magazine in 2014 published an article, Untethered by Andrew Chaikin. It listed the correct speed of the MMU at 45 mph. And went further, stating that the battery drain meant it had to travel even slower, at a creep. It’s one of the few articles I have been able to find that listed the correct speed apart from a NASA publication. It’s an informative article but the speed differences between the Space Shuttle, the satellites and the MMU is ignored. Obviously, that controversy couldn't be addressed.)

MMU Video

Searching on YouTube I found Why he went into space without a rope by Phil Edwards. He produces a number of science and technology related videos and has a following of over 300k subscribers. His videos are well produced and this one features the development of space walks (EVAs) starting with the Gemini program and leading into the Space Shuttle and the MMU. (He ignores that the first spacewalk was done by Russian cosmonauts.)

In this video Edwards makes a trip to the National Archives to examine NASA videos not usually seen online. He did get some interesting footage although there is not much new here and featured the standard story of NASA’s alleged ground breaking development in allowing astronauts the ability to freely move about in space without being hindered by cables or life support gear.

Like everybody else, he left out the speed differences between Shuttle, the satellites and MMU. Releasing that information would doom making NASA look on the cutting edge of space technology and portraying the astronauts as heroes. Overall, it’s rather bland treatment of the subject only broken up with moments of Phil’s quirky humor. It does serve the purpose of keeping America’s space program propped up.

Only bloggers are going to give you the truth about this because we are free to go there. Untethered.