Page 1

ST31S147-01 silicone rubber ST12G316-01 cloth

ST11D024-01 cloth 11 layers

ST11M282-01 cloth



ST17M042-02 film 11 layers

ST12H327-01 fabric 2 layers ST11M282-01 cloth


Moon Boot

The story of the Apollo lunar overshoe and the race to walk on the moon.

David H. Mather

Published by Space Effects Limited, Durley, UK

David H. Mather

Moon Boot

The story of the Apollo lunar overshoe and the race to walk on the moon. Š D.H. Mather, 2014 All rights reserved. No part of this book may be reproduced in any manner in any media, or transmitted by any means whatsoever, electronic or mechanical (including photocopy, film or video recording, internet posting, or any other information storage and retrieval system) without the prior written permission of the publisher. Book design by Juice Communications, Alresford, U.K. Published in the United Kingdom by Space Effects Limited Knowle House Mincingfield Lane Durley Hampshire SO32 2BR U.K First edition, 2014


. Space


. Effects

CONTENTS A brief history of the space race - How it all began . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - The world’s first satellite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - The first man in space. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - The Mercury program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 - The first woman in space. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 - The first spacewalk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 - The Gemini program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 - The Apollo program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Project 812 - The Apollo moon boot 1966 -1972. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - Boot design no.1 - 1966. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - The second boot pattern - 1966 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - The third boot pattern - 1968 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

44 46 48 62

Construction and manufacture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Changes for the new spacesuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Molding of the sole. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The legacy of the zipper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Boot sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Training boots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Part numbers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Where are they now?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

68 70 72 74 76 77 78 82 84

Appendix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 Silicone in space. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 The Apollo space suit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 What happened to the Russians?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Official NASA portraits of the moon walkers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

For Joyce & Ken Mather

Right: How the world saw history being made. Over 600 million people around the world - the largest TV audience ever known - watched as a small camera attached to the lunar module captured a grainy image of Neil Armstrong descending the ladder to become the first human being to walk on the surface of another world. Following spread: Craters on the approaching moon as seen from Apollo 16, 1972. (NASA)

On May 25th, 1961 US President John F. Kennedy made his landmark speech pledging to land a man on the moon “before this decade is out�. This was quite a bold statement considering that America had only 15 minutes 22 seconds of manned spaceflight experience and had travelled just 116.5 miles from the surface of the earth. The moon was 240,000 miles away. If a man was ever going to walk on the moon he was going to need something to wear on his feet. This is the story of the boot that ended the space race.

How it all began Russia and America had been developing and improving captured German V2 rockets since the end of the Second World War. With increased range and reliability the rocket was seen as the ideal way of delivering an atomic bomb, being unmanned, virtually undetectable and wholly unstoppable. By the mid 1950s the Cold War was in full swing and the atomic bomb was on everyone’s mind. 1957 saw the start of the International Geophysical Year, an international science project to coordinate the collection of geophysical data from around the world, involving over 66 countries. For the two superpowers this was an opportunity not to be missed, for what could be more impressive to the watching world than launching something, anything, into space? America announced their intention to launch a satellite. Russia duly followed, but few thought the Soviets actually capable of doing it.


“In the name of peace� - a contemporary Soviet propaganda poster from the 1950s.


The Soviets recognized and exploited the full propaganda value of the space race.

“Navigation in space is open!”

“We were born to make the fairy tale come true!”


“I am happy - this is my work joining the work of my republic”


“Sons of October - pioneers of the universe!”

The world’s first satellite 1957 - USSR The Soviet Union saw space as the perfect means of demonstrating that they were capable of building large rockets. By 1957 Russia had succeeded in developing the world’s first intercontinental ballistic missile, the R-7. The brainchild of Sergei Korolev, it was fuelled by liquid oxygen and kerosene and was a successful adaptation of the German technology from the 1940s. To achieve the desired performance and range the central rocket was surrounded by four booster rockets that dropped away when spent. The first successful launch of the R-7 was on August 21, 1957 and following approval from the Soviet premier Nikita Krushchev, a small, spherical satellite was launched a few months later on the 4th of October. Krushchev’s aim was to publicise the Soviet Union’s capabilities, and with the launch of Sputnik 1 this was achieved with spectacular effect. For 92 days people around the world tuned in to hear the series of beeps transmitted by earth’s first artificial satellite. Less than a month later Sputnik 2 was launched with a dog named Laika on board. The world was stunned, but for the USA the message was clear: if the Soviet Union could launch a satellite, they could launch an atomic bomb.

Left: The R-7 rocket carrying the world’s first satellite blasts off from a launch site in Kazakhstan. (RIA Novosti/Science Photo Library) Right: Sputnik 1 (meaning ‘Fellow traveller 1’) was 22.8”/58cm in diameter, weighed 184lb/83.6kg and remained in orbit for 92 days. (RIA Novosti/Science Photo Library)


The first man in space 1961 - USSR On April 12, 1961 cosmonaut Yuri Gagarin became the first human being to escape the confines of earth’s gravity and to look down on his own planet. The power of Vostok 1, a converted R-7 intercontinental ballistic missile (ICBM), was sufficient not only to launch a man into space, but to place Yuri Gagarin into orbit where he spent 1 hour 48 minutes circling the earth before returning home.

Left: At 9.07AM local time Vostok 1 lifts off from Baikonur cosmodrome, USSR. (RIA Novosti/Science Photo Library) Right: Yuri Gagarin in a brief moment of contemplation before his momentous flight. Only three of the last seven test launches of the R-7 had been successful. (RIA Novosti/Science Photo Library)


The Mercury program 1961- 63 - USA Mercury was America’s first manned space program. The Mercury missions used a small, single-seat capsule, and for the first two missions the capsule sat atop a Redstone rocket. This was essentially a second-generation version of the V-2 rocket developed by Germany during WW2. On May 5, 1961 Alan B. Shepard, Jr. made a 15 minute 22 second suborbital flight to become America’s first astronaut. However, to match the Russians and boost their Mercury capsule into orbit around the earth the USA needed more power from their rocket. Like the Russians, they looked to their ICBMs to provide it. For the third Mercury mission a converted Atlas ICBM was used to launch John Glenn into space, and on February 20, 1962 he became the first American to orbit the earth. The six Mercury missions came to an end in May 1963 with Gordon L. Cooper orbiting the earth 22 times in 34 hours 20 minutes.

Left: Alan B. Shepard, Jr. sits atop a Redstone rocket for America’s first manned space flight. (NASA) Right: The Mercury astronauts: L to R: Top; Alan B. Shepard, Jr., Virgil I. Grissom, L. Gordon Cooper, Jr. Bottom; Walter M. Schirra, Jr., Donald K. Slayton, John H. Glenn, Jr., M. Scott Carpenter. (NASA)



The first woman in space 1963 - USSR On June 16, 1963, 26 year old Valentina Tereshkova became the first woman in space. The daughter of a tractor driver, a textile factory worker and keen parachutist, she spent 2 days 22 hours 50 minutes aboard her Vostok 6 capsule, sending back the first live TV pictures from space.

Photographs: RIA Novosti/Science Photo Library


The first spacewalk 1965 - USSR March 18, 1965 - Voshkod 2. Alexei Leonov became the first true spaceman, making the world’s first spacewalk that lasted 12 minutes.

The Gemini program 1965-66 - USA A gap of nearly two years followed the Mercury program before the USA returned to space with the two-man Gemini missions. The main goals of these missions were to prove that long duration spaceflight, docking and extra-vehicular activity (EVA- working outside the spacecraft) were possible, all these elements being essential for the planned moon landings. The larger, heavier Gemini capsule was launched by another converted ICBM, the two-stage Titan 2. There were a total of 12 Gemini missions, and on June 3, 1965 the Gemini 4 mission gave America their first spacewalker - Edward H. White II. Gemini 7 set a new world endurance record, remaining in orbit for 14 days - approximately twice as long as the proposed Apollo moon missions. The Gemini program came to an end in November 1966 with the Gemini 12 mission. The problems of docking, working in space and extra-vehicular activity had all been solved. The USA had pulled ahead of their Soviet rival and the way to the moon was now clear.

Left: Ed White makes America’s first spacewalk. (NASA) Right: Gemini 7 keeping station, photographed from Gemini 6. (NASA)


The Apollo program 1967-1972 - USA The Apollo missions were the culmination of six years of American spaceflight. The three-man Apollo missions built on the lessons learned from the Mercury and Gemini programs to accomplish the ultimate goal - the exploration of another celestial body, probably man’s greatest achievement. Initially there was tragedy with the death of the Apollo 1 crew in a fire on the launch pad. There was failure with an explosion aboard Apollo 13, aborting their moon landing, but ending in success with the safe return of the crew. But these setbacks only strengthened resolve and served to remind the world what a dangerous endeavour space exploration really was, and something not to be taken lightly.

Left: Launch of Apollo 15 carrying the first lunar rover, July 1971. (NASA) Right: Earthrise - On December 24, 1968 Apollo 8 successfully reached the moon and orbited ten times before returning, bringing with it the first views of our home planet seen in its entirety from outer space. (NASA)


The missions: Apollo 7 was the first manned Apollo flight and tested the command module in earth orbit. Apollo 8 was the first Apollo mission to reach and orbit the moon. Apollo 9 flew the lunar module in earth orbit and tested the Apollo pressure suit in space. Apollo 10 was a dress rehersal for the lunar landing, taking the lunar module within 9.5 miles/15.2km of the moon’s surface. Apollo 11 was the first of 6 successful moon landing missions, with 12 astronauts eventually walking on its surface. For the moon missions the command module pilot (CMP) remained in orbit around the moon in the command module, whilst the commander (CDR) and lunar module pilot (LMP) descended the 60 or so miles to the surface of the moon in the lunar module (LM). The base of the LM then served as a launch platform, with only the top section lifting off and returning the two moon walkers back to the command module waiting in orbit. Before re-entry the cylindrical section of the command module was jettisoned and all three astronauts re-entered the earth’s atmosphere in the conical top section, the only part of the huge Saturn V rocket to return to earth.

Left: The command module (CM). (NASA) Right: Coming in to land - craters on the moon’s surface as seen from the lunar module Challenger. Apollo 17, 1972. (NASA) Overleaf: The lunar module starts its descent to the surface of the moon. Apollo 12, 1969. (NASA)



Left: On the moon - the surface of the moon as seen from the lunar module Challenger. Apollo 17, 1972. (NASA) Right: Commander Charles Conrad climbs down the ladder of the lunar module to become the third man to walk on the moon. Apollo 12, 1969. (NASA)



This page: The plaque attached to the leg of the first lunar module. Apollo 11, 1969. (NASA) Right: Buzz Aldrin descends the ladder of the lunar module, photographed by Neil Armstrong. Apollo 11, 1969. (NASA)



Edwin ‘Buzz’ Aldrin’s moon boot in the lunar dust. Apollo 11, 1969. (NASA)

The single footprint shot ‘...(I) moved on to my next task, the “scuff/cohesion/adhesion” activity. With each step, I purposefully kicked up the lunar dust with my boots. I continued to be intrigued by the dust, as fine as talcum powder. It exhibited a most unusual quality. I must have kicked about a halfdozen sprays or more, and each time the dust flew out in front slightly, landing in a perfect semicircle, every grain spraying out uniformly and equidistantly without any rippling effect. I related my observations to Houston, and thought, This is surreal, how each grain of moondust falls into place in these little fans, almost like rose petals.” ‘Nearby, with the camera in hand, I searched for a relatively flat area of the surface undisturbed by my dust-kicking, so I could take a photograph of a footprint. Finding a good spot, I first took a picture of the pristine surface; then, right in the middle of that flat area, I put my boot down, and then I moved my boot away and took a picture of that. Framed in the photo was the evidence of man on the moon - a single footprint, showing in perfect detail a reverse mold of the treads from the bottom of my moon boot.’


“That is kind of lonely looking, I thought. So I’d better put my boot down, and then move my boot away from the footprint, but only slightly so it’s still in the frame, and take a picture of that.” These were my small contributions to our lunar photography, but that single footprint shot became one of the most famous photographs in history, and a symbol of man’s need to explore.’ - Buzz Aldrin, Magnificent Desolation.




Left: The last man on the moon. Gene Cernan stands between the US flag and the lunar rover. Apollo 17, 1972. (NASA) Right: Ed Mitchell drilling core samples. Apollo 14, 1971. (NASA)


Left and right: In search of samples in the Taurus-Littrow valley. Apollo 17, 1972. (NASA)



Left: Gene Cernan beside the last lunar rover. His camera rests on the driver’s seat. Apollo 17, 1972. (NASA) Right: The US flag provides the only color in a grey, airless landscape. Apollo 12, 1969. (NASA)



Left: Coming home. Armstrong and Aldrin return from the lunar surface to Mike Collins in the orbiting command module. Apollo 11, 1969. (NASA) Right: The imprint of Buzz Aldrin’s moon boot in the lunar dust. Apollo 11, 1969. (NASA)


The Apollo moon walkers Apollo 11 : July 20, 1969 Neil A. Armstrong (CDR) Edwin E. Aldrin (LMP)

Apollo 12 : November 19, 1969 Charles Conrad, Jr. (CDR) Alan L. Bean (LMP)

Apollo 14 : February 5, 1971 Alan B. Shepard, Jr. (CDR) Edgar D. Mitchell (LMP)

Apollo 15 : July 30, 1971 David R. Scott (CDR) James B. Irwin (LMP)

Apollo 16 : April 20, 1972 John W. Young (CDR) Charles Duke, Jr. (LMP)

Apollo 17 : December 11, 1972 Eugene A. Cernan (CDR) Dr. Harrison H. Schmitt (LMP)


Project 812 - The Apollo moon boot 1966-1972 Whilst there is gravity on the moon there is no atmosphere. Temperatures can vary wildly in the complete vacuum of space, from +212F (+100C) in the sunlight, hot enough to boil water here on earth, to -233F (-147C) in complete shade, cold enough to take that boiling water and quickly freeze it. Such instant temperature changes are a difficult concept to grasp here on earth where the density of our atmosphere makes such transitions from sun to shade far less extreme. The lunar surface posed another equally challenging problem. Unmanned US Surveyor probes had obtained close-up images of the lunar surface and had even taken samples to try to determine if the terrain was safe for a manned landing. No one could say for sure, nor could they tell just how deep and how soft the surface actually was. For an astronaut to be able to survive and accomplish meaningful tasks in this harsh, unforgiving and largely unknown lunar environment, NASA would need a completely new, more flexible and more durable space suit than those previously used on the Mercury and Gemini programs.

Left: Charlie Duke braves the extreme, harsh environment of space protected only by his space suit. Apollo 16, 1972. (NASA)


Boot design no.1 - 1964 Original thoughts In March 1962 NASA announced the Apollo suit competition, calling for a spacesuit for the upcoming moon missions that could be used for lunar exploration. There was fierce competition with thirteen companies entering, some of whom had joined forces to produce eight submissions. Amongst them were Hamilton Standard, who were chosen to be the overall suit system provider, with International Latex Corporation*, who had submitted their AX1L suit for the competition, as subcontractor for the pressure suit. By mid-1964 continued development of the AX1L resulted in the A-4H suit which was supplied with heavy and restrictive thermal overgarments. This early prototype suit was notable for the fact that it featured the first of the three eventual and distinct lunar boot designs. The A4H boots were worn over the pressure suit and outer thermal protection, and took the form of slippers held on by Velcro straps. The thermally insulating sole was made of a composite material that consisted of a shoe bottom with 1� (25mm) spacers separating the bottom from the top portion. This created a raised platform and distanced the astronaut from the heat and cold of the lunar surface. Like the thermal overgarments, the early A4H boot design, whilst undoubtedly effective, was to prove short-lived. It did, however, provide a very useful starting point for discussion and something on which the ILC engineers could now build. Two years of testing saw NASA still searching for a suit that would meet its requirements. And so, in June 1965, NASA announced a second Apollo suit competition. Having ended their contract with Hamilton Standard in March 1965, ILC now reentered the competition with David Clark and Hamilton Standard as a potential main contractor. ILC submitted their own suit design for the second NASA Apollo suit competition and won with their AX5L suit. In August 1965 the now-renamed Government and Industrial Division of ILC was awarded the prime contract for the Apollo lunar space suit.

*The International Latex Corporation: Founded in 1932 the International Latex Corporation patented a rubber girdle design for women in 1940 that would not tear at the seams. In 1947 ILC reorganized into four divisions, one of which was the Metals Division which made life vests, life rafts and anti-exposure clothing, as well as display racks for the girdles, swim caps and baby pants for Playtex, another of the four divisions and known universally for their ladies undergarments. In 1952 the Metals Division started making high altitude helmets for the US navy and air force, and expertise gained in rubber compounding and dipping techniques soon saw production expand to include the entire pressure suit. Photographs: Left: Bill Ayrey, ILC Dover, LP. Right: NASA



The second boot pattern - 1966 A change of direction A space walk was scheduled for Apollo 9 and NASA needed a suit capable of being worn outside the spacecraft in the vacuum of space and in the harsh lunar environment a suit configuration that NASA referred to as the Apollo Extravehicular Mobility Unit (EMU). Suit development had been ongoing since the 1965 suit competition. In late 1966 ILC took their existing model A5L* suit, a pressure suit that was being used for training at that time, upgraded it to a flight quality standard and made a series of additions to make it suitable for extra-vehicular activity (EVA), thereby creating the A6L suit. These additions comprised a helmet with reflective visor, a life support system and an emergency oxygen supply both contained within a removable, portable backpack. Also included were a set of slip-on thermal overgarments to protect against heat and cold, including overgloves and overshoes. Moon boots. This second proposal for a boot was quite a leap forward from the earlier concept. It was more rugged, more durable and considerably more practical.

Left and right: Three views of the A6L suit with early proposals for thermal protection including gloves and moon boots. (Bill Ayrey, ILC Dover, LP) * A = Apollo program, 5 = 5th in the series, L = ILC.


Where to start? So how did the engineers at ILC arrive at this second version? Where did they start to design a boot to walk on the surface of the moon? One of the stories told by a retired ILC employee to ILC’s spacesuit historian, Bill Ayrey, was how one of the engineers went to the local sporting goods store and bought several boots to look at their tread. It seemed as good a place to start as any.

Richard Pulling (left) and Bob Wise, the two engineers who worked on the lunar boot, pour over an engineering drawing showing the fabric upper and ankle strap arrangement on the boot. Note that a top strap is not shown at this stage. (Bill Ayrey, ILC Dover, LP)


After much deliberation the engineers decided to keep it simple. They produced an initial design for the sole that was approximately ovalshaped with raised sides, rising at the heel and the toe, forming a nose covered in a series of vertical ribs for grip.

Complex tread patterns were rejected in favor of a series of large, transverse ribs for improved traction in the lunar dust. As well as providing grip on the lunar surface the ribs of the sole would serve two other functions: the raised ribs were 3/16” (4.5mm) thick and would afford added insulation and protection from heat, whilst the thinner depressions would provide flexibility in cold conditions. The thickness of the sole in these depressions was merely 1/16” (1.4mm), and yet it did not tear or split, something only made possible by the remarkable properties of the silicone used. The ribs were also spaced so as to fit the rungs of the ladder on the lunar module. With the design of the sole in hand they looked around for a suitable material from which to make it. Bill Ayrey recalls: “(the moon boot) had to be made using the technology we had at the time. ILC was good at dipping various components such as convolutes and other rubber components, so using the silicone to form the boot tread was not hard to do. Model makers had to make the various molds to form the tread, then our very experienced sewers simply had to sew the soft goods to the reinforced silicone.” The ILC engineers approached General Electric (GE), who had been supplying the aerospace industry with silicone adhesives, sealants and lubricants since the 1940s, with a series of requirements that included a wide temperature tolerance, fire retardancy, resiliency, and adaptability to ILC’s molding techniques. They settled on a GE compound of silicone called RTV-630, a silicone that had been successfully used as a high-strength moldmaking material and potting compound for electronics.


Far left: The toe of the boot with vertical ribbing. Left, top: ILC’s A6L suit in EVA configuration. (NASA) Right: Second pattern boot sole with simple ribbed design. Note the castellated effect at the nose formed by the vertical ribbing at the toe.


The fabric uppers Access to the boot was gained via a vertical zipper at the rear of the boot, with the base of the zipper ending in a ‘U’ shaped cutout at the the top of the heel in the silicone sole. The zipper was covered by an insulated Velcro-lined flap to prevent it from freezing or becoming too hot on the lunar surface. Inside, a long loop of webbing sewn just below the zipper helped the astronaut pull the boots on. Initial second pattern boots featured a tall fabric upper that was calf length, approximately 16½” (420mm) high. These boots were given the NASA part number of A6L-206000. A shorter, ankle-length version of this upper was also tried.

The uppers of the new boot were made from a high temperature material (HT-1) called Nomex, a fire-retardent fabric manufactured by DuPont. The inner lining was a rip-stop nylon. Sandwiched between these two fabrics were several layers of Mylar* film for insulation.

*- Aluminized Mylar was developed by DuPont in the 50s and 60s. Aluminumcoated Mylar was light, a good insulator and extremely strong and was used throughout the Apollo spacesuit. The film itself was perforated to allow any oxygen trapped within the layers of the suit to escape when the astronaut left the pressurized spacecraft for the vacuum of space.


Far left: Second pattern boots with tall uppers during early trials. (NASA) Left and right: Second pattern boots with the shorter upper design. (NASA)



An example of a second pattern boot with the early design of blue silicone sole. The example pictured here has a model number of 1003 and is dated October 1966.

Far left: Second pattern boots with the short upper design (NASA) Boot images: Rick Mulheirn


Boot #2

Changes to the sole Second pattern boots were used extensively for early EVA tests and training for the Apollo missions. They provided valuable data for future designs and confirmed the suitability of RTV-630 silicone as the ideal material for the soles. The boot soles were examined for wear and damage caused during training and the data was used to refine the design and improve both strength and durability. The resulting design featured several notable changes: The height of the nose was increased by approximately 3/5” (15mm) to provide more room and reduce internal abrasion and wear of the space suit at the toe. Wear was found to be highest at the heel and the toe, resulting in perhaps the most noticeable change to the original sole design. To improve durability the vertical ribs at the nose of the boot were shortened and no longer ran all the way down to the base of the sole. A thicker, smoother more substantial toe was also incorporated into the design. The design of the tread pattern was also modified to further strengthen the heel and toe areas by extending the width of the crescent-shaped toe and heel ribs to the edge of the sole.

Above: Revisions to the original design included a taller and more durable toe section. Right: Changes to the second pattern sole design. The final version is shown on the far right and is the design that was used on the moon.

Bill Ayrey adds: ”the final version of the tread came about as a best-guess as to what would work on a lightly packed lunar base.”


This was the final design of the sole and the version that was used for all the moon landings. Brand new molds were created by ILC’s modelmakers to produce the new shape.




To test the new sole design further, boot prototypes were manufactured using the same design of uppers as previously tried. As before, boots were produced with uppers in both tall and short versions, both still incorporating the rear zipper arrangement for access. The uppers on the tall version illustrated here were made from Nomex on the outside with only a single layer of perforated Mylar film, a single layer of nylon fabric and a layer of very open-weave mesh sandwiched inside. The lining has changed from black to an offwhite and there is no rip-stop used for the lining of the zipper flap. The long webbing loop to aid donning is still retained. Produced after October 1966, these boots are extremely rare, further development of this particular pattern of boot being halted only a few months later by the tragic fire of Apollo 1 in January 1967.

Right: Three views of the second pattern boot with revised sole design. Note how the base of the zipper cuts into the top of the silicone rubber sole at the heel.




The third boot pattern - 1968 The final version Following a comprehensive review of materials after the Apollo 1 fire the engineers at ILC returned to the drawing board and scrutinized every aspect of the boot design. A third, and what would turn out to be the final, version of the boot appeared in early 1968. The revised design of the silicone sole from the second pattern boot had been retained, but everything else about the design had changed. Ease of access to the boot had always been an issue and the tall fabric uppers of earlier prototypes had now been discarded. A new, short, ‘folded’ design created a considerably wider opening at the neck and made the boot far easier to put on and take off whilst suited. A finger loop at the back was added to assist the process. The earlier rear zipper and flap arrangement was replaced by a combination of press studs and an adjustable ankle strap, making the boot more secure and less vulnerable to the fine, abrasive lunar dust.


Above: The same sole was used for the third pattern boot but the uppers were radically altered from the earlier designs. Left: An early NASA photograph of the lunar spacesuit in EVA (extra vehicular activity - or moon walk) configuration. Note the earlier, second-pattern boot (with short Nomex uppers) that can be seen on the table in the background. (NASA) Right: An early photograph of Neil Armstrong training for his historic ‘one small step’ using the third pattern lunar overshoe. (NASA)


Teething troubles A minor problem with the folded neck design was revealed during training for Apollo 11 where it was found that the top of the boot would come undone quite easily if snagged. A simple and quick fix was to wrap masking tape around the top of the boot and continue on with the training program. Whilst this was undoubtably effective in the short term, a more permanent, moon-worthy solution was needed.


Left: Buzz Aldrin with the hastily modified boot during training for Apollo 11. (NASA) Right: Buzz Aldrin returns to training with the masking tape ‘quick fix’, whilst Neil Armstrong’s boots, seen to the right, have yet to receive the upgrade. (NASA)


One final addition It was clear that the press studs alone were not going to be strong enough to secure the neck of the boot. The solution came in the form of a Beta Cloth top strap with a wide tab and a third press stud. The wide tabs were easy to handle with the lunar gloves and were designed to be worn facing inwards to minimise the chances of snagging. This simple addition worked well, and this modified version was to be the final variant, and the configuration used for all the manned moon missions. Officially termed ‘lunar overshoes’ by NASA, the world would come to know them by a more familiar name moon boots.

Left: Edwin ‘Buzz’ Aldrin. Early days of training for Apollo 11 testing the new boot design. The top straps have yet to be added. (NASA) Right: The final version of the boot with wide top strap. Ease of access was greatly improved with the folded neck design. A series of press studs and straps kept the boot secure.



Construction and manufacture As a result of a review of materials following the tragic Apollo 1 fire in January 1967 the Nomex fabric used in the second pattern boots was discarded as an outer covering. Designed to insulate against radiation, heat and cold whilst on the moon, the uppers were now made from a combination of a fireproof, woven Teflon-coated fibreglass fabric called Beta Cloth*, and a cloth of woven chromium steel fibres used to improve thermal shielding and protect against abrasion, known as Chromel-R.** For Apollo 11,12,13 and 14 the uppers were constructed from (outer to inner layer): one layer of Chromel-R/Armalon Beta Cloth, two layers of ST12H327-01 fabric (a Beta marquisette and Kapton*** film, laminated together using a thermosetting polyester adhesive), eleven layers of ST17M042-02 aluminized Mylar film (a perforated polyetheylene terephthalate film, aluminized on one side) interleaved with ten layers of ST11D024-01 Webril non-woven polyester fabric. The inner lining of the boot was ST12G316-01 Armalon (Beta Cloth coated with TFE Teflon on both sides). For added insulation two extra layers of Beta marquisette were interleaved between the Kapton film on the soles as well as a Fluorel (4484/FWDT1) liner in the sole of the boot. (Fluorel was also used for the chest connector area on the A7LB suit). All the metal components were of stamped, pressed and welded construction. Made from high-grade, non-magnetic stainless steel they were bead-blasted to produce a matt surface finish. The press studs were supplied by Scovill Fastners (Dot), Clarkesville, GA.

*- Beta Cloth was manufactured by the Owens Corning Corporation (Owens Corning part No. 4190B). It weighed 6.3oz per square yard and cost approximately $7.00 per square yard in 1967. There were three types of Beta Cloth used throughout the Apollo program - Beta Cloth ST11G245-01, ST11G332-01 (Beta Cloth woven from TFE Teflon-coated Beta yarn) and ST12G316-01 Armalon (Beta Cloth coated with TFE Teflon on both sides). The latter material was used for the lunar boots and EV gloves for Apollo 11 through to 14. However, Beta Cloth had a high reject loss during production and also proved to be quite fragile in use. It tended to split and fray if repeatedly and sharply creased, and it was eventually replaced with T162 Teflon fabric for both the boots and the later A7LB suit. **- Chromel-R was qualified to withstand heat to 1200ºF (650ºC) and was, at the time, the world’s most expensive material. In 1967 initial development orders of Chromel-R cost $2775 per square yard. ILC’s Bill Ayrey tells of how “...we actually locked the roll up in a vault and only took it out when cutting pattern pieces”. The wire filaments (thread) for Chromel-R were produced by Hoskins, inc. and it was then bundled and woven into a cloth by Prodesco, inc. in Perkasie, PA. The official NASA designation for Chromel-R was ST11M282-01 cloth. ***- Kapton was a polyamide film developed by DuPont that did not shrink, melt or burn at high temperatures and, being aluminum-coated, also reflected heat well.


Left: Assembly of the lunar overshoe showing the layers of Mylar film used for insulation. The employee is actually holding a lower leg section of the suit ITMG (see photo p.92). Note the two protective covers for the boot soles in the foreground. (National Air and Space Museum, Smithsonian Institution (NASM 83-15833))

Changes for the new spacesuit In 1970 a new suit design was introduced for the last three Apollo missions* along with some minor modifications to the boot. Whilst externally unchanged, an internal toe plate was added for greater durability in the toe area. The two layers of Kapton/Beta marquisette laminate were also removed. Originally the Kapton was incorporated as part of the standard lunar ITMG construction where it was used to improve flame protection. Its use in the boot was found to be redundant due to the protection afforded by the foot (spat) of the ITMG and the Fluorel liner in the sole of the boot. The elimination of these two layers reduced the weight of a pair of lunar boots by around 1/2 lb (0.23kg). To test whether the new suit design met its design parameters (fexibility, range of motion, thermal performance etc.) a complete suit was produced. All suit components were included in the tests, regardless of whether they had been changed or not, and all parts carried the DVT (Design Verification Testing) prefix to the serial number. In total three DVT A7LB suits were produced. The boots seen here are from suit DVT-1 and bear the serial number A7LB-106062 (-01 or -02 for left and right boot). A document from NASA to ILC dated May, 1970 approves the new lunar boot top assembly drawing (A7LB-106062) and notes ‘... the incorporation of bundle drawn “Karma”** metallic fabric as the outer layer...’ for the A7LB boot. In 1967 there was much concern over the cost and delivery rate of Chromel-R cloth and whether a 100-1/2 mil, 70-1/2 mil or 49-1 mil filament should be used. Supply was a major issue. The smaller filaments were able to be produced at a faster rate, but the larger filaments were cheaper. Further development of metal filament cloth eventually addressed almost all of the earlier concerns and created a more flexible cloth with a slightly larger weave that was softer in appearance, more durable and faster to produce. The A7LB development boots shown here appear to have been manufactured using this later cloth. Note the softer, smoother appearance of the grey metallic fabric. For whatever reason (possibly due to the early termination of the Apollo program) this cloth was not carried over to flight-certified A7LB boots which continued to use the earlier cloth with its distinctive creased appearance (compare with the image on previous page and the boots of Apollo 17 moonwalkers Gene Cernan and Harrison Schmitt on pages 84 to 87). Whilst Beta Cloth was dropped in favor of Teflon fabric for the new suit these DVT boots were made using the earlier cloth. * - See appendix P.94 ** - Karma is a trade name and refers to the (80 Nickel - 20 Chromium) wire fibers used in the production of the cloth.


A pair of lunar overshoes made for design verification testing DVT of the new A7LB Apollo spacesuit. (All photographs Dennis Gilliam)


Molding of the sole The soles of the Apollo moonboot were made from a silicone resin manufactured by General Electric (GE). The actual compound used was RTV-630, a dimethyl RTV (Room Temperature Vulcanizing) compound with a thermal tolerance ranging between +400ºF to approximately -75ºF (+204ºC to -54ºC). It was able to withstand the considerable temperature variations found on the surface of the moon. The official NASA designation was ST31S147-01 silicone rubber. RTV-630 proved to be fire retardant, very strong and very resilient. It could be stretched to three times its original length and had a tensile strength of 850psi. Originally used as a potting compound for electronic components, for mold making and as an elastomer it proved to be very adaptable to the low volume molding techniques favored by ILC. To cast the boot soles RTV-630 was hand-poured into the hand-tooled metal mold. A central core was introduced and the whole cured in an oven. Two layers of Beta Cloth were then added to give extra strength and another layer of silicone was painted over the top. The sole was then placed into a bag where all the air was drawn out. It was then placed under heat lamps to cure the silicone. Once removed from the mold the soles were then cured in an oven at 200ºF (120ºC) for a further two hours.

Right: A series of stills taken from a contemporary documentary shows an OLGE-size sole being cured under lights and demolded by hand. (NASA/ILC)


The legacy of the zipper As seen earlier, the third pattern boot used the same sole as the modified second pattern designs. This left a small problem. The second pattern designs featured a zipper at the rear for access, and to accommodate the base of the zipper the sole had a ‘U’ shaped cutout at the heel. And so did the molds. However, rather than discard the molds these ‘U’ shaped holes were simply filled in. They were then used to make all the soles for the manned moon missions.


If you look very closely at the back of an original moon boot you can still see a very faint trace of where the zipper used to be.


Boot sizes The moon boot was produced in two sizes – OMED and OLGE, and the difference can be seen in the number of ribs on the sole of the boot there are eight on the OMED and nine on the OLGE. The soles measure 13¼” (336mm) x 6” (52mm) for the smaller size and 14½” (368mm) x 6½” (165mm) for the larger size. Astronauts that wore a street shoe of size 11(US) or larger would use the OLGE size. For example, Jim Lovell of Apollo 13 wore a size 11(US) shoe, whilst Neil Armstrong’s shoe size was 9½(US).


Testing The boot soles were tested at NASA’s simulated moon surface laboratory where an area of slag, limestone and feather rock served to duplicate the most severe surface conditions anticipated on the moon. Despite suffering some surface wear and tear, it was found that the thermal properties of the boots were not affected. As it turned out, the moon ‘soil’ was much finer than expected. The lunar dust could be easily brushed off, and there was little or no surface degradation of the sole when examined by the astronauts. The lunar overshoe was one of the few components whose design, at least externally, remained unchanged throughout the Apollo moon landings - a fine testament to the essential correctness of the final design.


Training boots The first batch of boots were made with Chromel-R uppers but without the top strap which was added later. The success of the top strap versions relegated these early boots to a purely training role. Boots were subjected to repeated use and considerable wear and tear during the arduous training program. Whilst it was always desirable, and preferable, to use exactly the same type of boot for training as for the actual mission, gloves and boots were the first and most expensive items of equipment to wear out. The uppers were mainly constructed from Chromel-R, a woven stainless steel fabric which was never intended for such intense and continued use. It tended to work-harden, fatigue and eventually split along any crease that formed, and at approximately $3000 a yard (1969) it was extremely expensive. In April, 1969, at the request of the Apollo Program Office at the Manned Spacecraft Center, ILC’s engineers produced a new training configuration of the lunar boot which used Teflon-coated Beta Cloth in place of Chromel-R in an attempt to extend their useable life and reduce costs. In May, 1969 the configuration was modified to substitute the more durable T162 Teflon Fabric in place of the Teflon-coated Beta Cloth (ST11G332-01). To ensure the same level of flame protection one layer of Beta Fabric 4484 was introduced between the Teflon Fabric and the insulation plies.


Left, right and above: Training boot for Apollo 17 astronaut Gene Cernan. NASA part number of A7L-106015 (-05 left and -06 right boot). The top strap has been removed from this boot at some point. (Photographs courtesy Heritage Auctions) Far left: Astronaut Dick Gordon suits up for a training session. Note the all-white training boots with top straps. (NASA)


Left: Jim Lovell and Fred Haise during training for Apollo 13 wearing both types of lunar overshoe. (NASA) Right, main image: Apollo 13 lunar training with all-Beta Cloth boots. (NASA) Far right, top and bottom: Charles Conrad and Alan Bean train for Apollo 12 with early versions of the lunar overshoe. Note the lack of top straps on either pair of boots. (NASA)


Part numbers The spacesuit used for the early Apollo missions carried the model designation of A7L, whilst the later missions of Apollo 15, 16 and 17 used a redesigned version of the suit which was given the modified title of A7LB. Part numbers for fittings and equipment for these suits tended to start with their associated suit designation, however some components developed for the earlier A6 models of suits were also used on the later A7 suits. The final version of the moon boot sole was designed whilst still under the A6 stage of suit development, so the molds that were used to manufacture all the boot soles worn on the moon still carried the A6 designation. If the part numbers are to be taken as sequential in issue, part number A7L-106005-01 represents the earliest of the third pattern boots to be found in the Smithsonian’s reserve collection. A part number appears not to necessarily denote a type of construction or design, rather a stage in production or design. Part number A7L-106015 was used variously on boots of quite different construction and is found on both prototype and training boots. Boot serial number 001 with this part number is a size OMED and is, at least externally, to all intents and purposes the final design, featuring a top strap and Chromel-R uppers. Serial number 017 with this part number, on the other hand, has Chromel-R uppers but no top strap. This part number is also found on some all-white training boots. Flight-configured Lunar overshoes for Apollo missions were given the official NASA part number of A7L-106043 (usually followed by a zero and a number denoting left or right boot) when used with the A7L spacesuit, and part number A7LB-106062 when used with the later A7LB spacesuit. Despite the change in designation, the external design of the boot remained unchanged. At the end of April, 1969 work was stopped on lunar boots with the serial numbers 057, 058, 059 and 060, all of which carried the part number A7L106043 (-05 & 06). ILC’s engineers were requested to release a new training configuration of boot which used Teflon-coated Beta Cloth in place of Chromel-R. The new configuration was allocated to pressure garment assemblies (PGAs) A7L-082,083, 084 and 085. The PGA part numbers were not changed to reflect the different lunar boot configurations.


ILC later received instructions from The Manned Spacecraft Center to stop production on 16 pairs of lunar boots, originally to be designated as training boots. On June 23, 1969 they received a directive to proceed with the manufacture of these boots as flight-configured A7L-106043-05 & 06 boots using Chromel-R uppers. Boots with part numbers A7L-106043-01 & 02, 03 & 04, 05 & 06 and with serial numbers 029, 030, 032 through to 038, 043, 044, 049 through to 056, 061 and 062 were all built with Chromel-R uppers. The part and serial numbers, identification code, boot size and manufacturer were all printed on the finger loop. Where a boot was assigned to a particular astronaut, a label with their name was sewn inside on the tongue of the boot.

Left, right and above: Three views of the final design of the Apollo lunar overshoe as used on the moon. This particular boot was made for Jim Lovell of the ill-fated Apollo 13 mission.


Where are they now? Only the top section of the lunar module lifted off from the surface of the moon. It used the base of the lunar module as a launch platform and its small rocket motor had limited thrust, so weight was a serious consideration. It was far preferable to return scientifically important moon rocks than man-made equipment, and as a result many items were left behind on the moon’s surface. These included the life support backpacks, cameras, many gold-visored helmets and moon boots. Neil Armstrong’s boots are still there on the moon, as are those of Buzz Aldrin and eight other moonwalkers. Only two pairs of boots ever came back from the moon - those of the crew of Apollo 17, Harrison Schmitt and Apollo 17’s commander Gene Cernan the last man to walk on the moon.

The moon boot was never used again.

Left: Lunar dust covers the toes of Schmitt’s moon boots. Apollo 17, 1972. Photo by Mark Avino, National Air and Space Museum, Smithsonian Institution. (NASM 2008-9210)

Following page spread: Harrison “Jack” Schmitt’s lunar boots worn on the moon’s surface and returned to earth. Apollo 17, 1972. Photo by Mark Avino, National Air and Space Museum, Smithsonian Institution. (NASM 2008-9211 and 2008-9213)



Silicone in space. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90-91 The Apollo space suit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92-95 What happened to the Russians? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96-113 Official NASA portraits of the moon walkers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114-129

Left: The valsalva device, seen here just beneath Neil Armstrong’s chin, was made from the same silicone as the boot soles, as were the seals for the feed port on the side of the helmet and the ear pieces for the communications carrier (Snoopy cap) all seen here in blue. The pressure helmet, or ‘bubble’, also used silicone to seal it to the red aluminum neckring, the seal seen here as a bluish-white ring. (NASA)


Silicone in space General Electric had developed the first silicone rubber for use in aircraft superchargers in the early 1940’s, and silicones have been used in their various forms in aircraft construction ever since. Silicone lubricants and adhesives were used extensively on weather satellites and space probes, and silicone rubber was used throughout the manned space program from the very beginning. It was used as a sealant around rivets and bolts on the Mercury spacecraft and as adhesives, sealants, lubricants, insulation and gaskets on the Gemini spacecraft. Silicone was also used extensively throughout the Apollo spacesuit. As well as being used to mold the sole of the moon boot, RTV-630 was used to pot the microphone booms of the communications carrier (Snoopy cap) worn by the astronauts. The same RTV-630 was used to create a valsalva device which was mounted inside the rim of the bubble and allowed the astronaut to ‘pop’ his ears. RTV102 was used to seal the polycarbonate bubble helmet to the metal neck ring and F-50 silicone grease lubricated the nylon-coated steel restraining cables of the pressure suit. Silicone sealing gaskets were used in the connectors, whilst wrist and elbow joints were lubricated with G-300 silicone grease. The palms of the lunar (EVA) gloves were coated with silicone and the fingers were tipped with RTV-630 silicone caps to provide additional grip.

Right: the underside of the fingers and palms of the Apollo gloves were coated with clear silicone for grip. The blue silicone finger tips provided protection against heat and cold as well as a degree of tactility.

Previous page: Dr. Harrison Schmitt holds the US flag whilst the earth appears as a distant oasis in the blackness of space. Apollo 17, 1972. (NASA)


The Apollo space suit At the time, the Apollo space suit was the most complex tailored outfit ever created, and the most expensive. The later suits for the last three missions each cost approximately $250,000. Each suit was made up of two main components - a blue pressure suit - effectively a pressurized, flexible, gas-tight rubber bladder - and a white multi-layered, thermally insulating oversuit that was permanently attached to the pressure suit underneath. Together the whole assembly was called the pressure garment assembly, or PGA. The astronaut entered into the PGA via a zipper in the rear of the suit and was sealed into the PGA by his gloves and a clear bubble helmet. To walk on the moon the astronaut added a backpack containing, amongst other things, oxygen supply, electrical power and radio. On his chest he attached a control panel and connected up the hoses of the backpack to the front of his suit. Onto his bubble helmet he clipped a lunar extra-vehicular visor assembly (LEVA), a protective overhelmet with a clear visor, an adjustable gold visor and positionable sunshades. He swopped his gloves that he wore for the launch for another pair that were internally identical, but covered with several layers of insulation and protection, and slipped on a pair of lunar overboots over the shoes of his white PGA.

Left: The blue pressure suit in its inflated state as it would be whilst walking on the moon. To work in these suits, grip objects and flex limbs the astronaut needed to overcome 3.9psi of internal pressure and the suit’s natural tendency to maintain the resting position seen here. The suit is shown with intra-vehicular activity (IVA) gloves that were worn inside the spacecraft during launch and re-entry. (NASA)
















Above: An early NASA illustration of the lunar spacesuit in EVA (extra vehicular activity - or moon walk) configuration. Note the early design of gloves with long gauntlets and without the later silicone fingertips. Right: The same pressure suit as seen left but now with the integrated thermal micrometeoroid garment (ITMG) on top. The gloves have been replaced by extra-vehicular activity (EVA) gloves worn during moonwalks. (NASA)


When all suited, the Apollo 11 spacesuit comprised of approximately 26 layers and weighed 189lbs/86kgs on earth, but only 31.4lbs/14.3kgs on the surface of the moon. The NASA designation for the Apollo spacesuit was A7L A for Apollo, 7 for 7th model, L for ILC Industries, the prime contractor. The suit was completely redesigned after Apollo 14 to allow the astronauts to bend more easily at the waist and knees, and to sit in the newly developed lunar rover. The new suit was given the model number A7LB.

Left: The many components of Neil Armstrong’s A7L moon suit. Below and to the left of the central suit is the liquid cooling garment (with single blue connector), worn beneath the suit on the moon to keep the astronaut at a constant temperature by circulating water through a series of interwoven tubes. Below and to the right are his lunar overshoes, or moon boots (one shown with uppers turned out to reveal Armstrong’s nametag). These were worn over the shoes of the suit shown in the centre of the picture. The PGA number of 076 shown is incorrect and actually refers to the serial number of the suit liner. Armstrong’s flown PGA was s/n 056 whilst his ITMG was s/n 063. (NASA) Right: The A7LB pressure suit was an evolution of the earlier A7L suit. The main differences were a wider seat, the location of the access zipper and the layout of the connectors on the front of the suit. The suit is shown here without the white thermal covering garment (ITMG) and with IVA gloves. Standing at the back, left to right; John Leshko, NASA Quality Inspector, John McMullen, ILC Systems Engineer and Steve Ruben, ILC Design Engineer. (Bill Ayrey, ILC Dover, LP)



What happened to the Russians?

Pic to do

What happened to the Russians? The logical end to the space race was the landing of a man on the moon, a goal expressed by US president John F. Kennedy in his 1961 speech to the US Congress. However, nowhere in that speech did he state that it should be before the Russians, but in the tense atmosphere of the Cold War at the time, it just seemed implied. When Neil Armstrong and Buzz Aldrin set foot on the moon the race was over. The Russians said that they had never intended to land a man on the moon. It was a waste of resources and a frivolous exercise. They were more interested in space stations.

The truth was rather different...

Left: The launch complex at Baikonur, Russia, circa 1969 where two enormous rockets dominate their surroundings. (NPO/RSC Energia) Right: Four locomotives on two sets of rails were needed to transport the Soviet moon rocket to the launch pad. (NPO/RSC Energia)



The Soviet manned lunar program 1964 - 1972 Sergei Korolev was chief designer of the Soviet rocket program and the mastermind behind the early Soviet space triumphs of Sputnik, Gagarin and Titov. In 1964 he was ordered to start work on a Soviet moon program. Unlike the three-man missions of Apollo, there were to be only two Soviet cosmonauts sent to the moon – one would remain in orbit around the moon and the other would descend to the moon’s surface - alone. Work progressed well and by the start of 1969 Russia had developed a fully functioning moon suit and built a lunar lander.

Left: The one-man Soviet LK (Lunniy Korabl-”lunar ship”) moon lander. (Alexander Popov)


Above: The window from which the cosmonaut would have guided the lander onto the surface of the moon. (Alexander Popov) Right: Another view of the moon lander showing the exit hatch (in blue) and the ladder down which the lone cosmonaut would have descended. (Alexander Popov)


The Russian moon rocket To launch the two cosmonauts and their lunar lander Russia had designed and built a massive rocket. The N1-L3 weighed 2820 tons and rivalled the American Saturn V in size. But for the Russians there was a problem. The program had been started in 1964 under the control of S.P. Korolev, but he died in 1966, and without him the Russian space program floundered. Unlike the Americans, the Russians had not developed large rocket engines, preferring to rely on smaller, tried-and-tested engines. To generate enough thrust the N1-L3 rocket needed 30 of these smaller engines to get it off the ground, as opposed to five for the American rocket. The resulting complexity was to be its downfall.

Left: The 30 engines of the N1-L3’s first stage produced a total of 4615 tons of thrust. (NPO/RSC Energia)


The first launch of the N1-L3 rocket was on February 21, 1969. After just 68.7 seconds a fire caused the engines to shut down, destroying the rocket. On July 3, 1969 the second rocket launch lasted only a few seconds before the engines once again shut down, resulting in the destruction of both the rocket and the launch complex. The third, and then the fourth and final launch both ended in a similarly dramatic fashion. The successful Apollo 11 landing on July 20, 1969 killed all Soviet political interest in the lunar program. The completion of the American moon program with Apollo 17 on December 19, 1972 sealed its fate. The rockets were cut up, with some parts being used in children’s playgrounds and all documents, moon suits and engines ordered destroyed. It would take decades, and the fall of the Berlin wall, before the exact details of the Soviet lunar ambitions were fully revealed.

Right: The Soviet moon rocket stood over 345 feet/105 metres high on the launch pad at Baikonur. (NPO/RSC Energia)


The Russian moon suit Like their American counterparts the Soviets had also designed a spacesuit to walk on the moon, but the Russian design was quite different to anything that had been seen before by either side. Before a moonwalk the Apollo astronauts needed to strap on various pieces of equipment to their soft pressure suits – radio, life support system, helmet visor, control panel etc. The Russian approach was to combine all these separate elements into what, in effect, was a small, self-contained, one-man spacecraft. They named it Krechet-94 (Falcon). The arms and legs of this new suit were of conventional design, being made from a soft, flexible bladder of rubberised cloth with restraining straps and cables. For reliability a second bladder was added as a backup in case of failure. But it was above the waist that the Russian suit really broke new ground. For the first time the torso, the helmet and the backpack were built as one rigid, integrated unit. Formed from 3/64� (1.2mm) thick AMG-3 aluminum, this hard upper torso design had several advantages. It did not expand when pressurised, nor distort when the cosmonaut bent and flexed his limbs. It was easier to seal and could be made to fit a wider range of cosmonaut sizes. The rigid torso also made it far easier to mount and connect items such as the control panel, radio, helmet, valves and bearings for the arms. Most importantly the life support system could be completely integrated into the suit. This made for a simple, reliable, onepiece suit that the cosmonaut could put on and take off easily by himself, an important consideration as, unlike the American Apollo program, the Russian moon walker would be leaving his crewmate to orbit around the moon whilst he descended, alone, to the surface of the moon. He would not have the benefit of a second crew member to help should things go wrong on the surface of the moon.

Left: The Soviet Krechet-94 moon suit with its original wheeled transport frame, used to support the suit’s considerable weight whilst on earth. Note the ring and thin black cable on the side of the control panel by the left arm which is used to pull the backpack door shut once inside.


The whole suit, including the helmet, was covered with an off-white colored, thermally insulating micrometeoroid overgarment similar to the ITMG used on the Apollo suit. The pockets were lined with leather and held a safety tether on the right thigh and umbilical connectors (to recharge the suit’s oxygen supply whilst being worn) on the left. The fixed helmet had a double glazed clear visor, as well as green and gold plated visors that could be retracted under a protective cover mounted on top of the helmet. The suit was capable of 10 hours of operation before requiring a recharge and weighed approximately 234lbs (106kg). The main disadvantage of this type of design was its bulk, but suit storage was less of a problem for the Russians than it was for the Americans as there were only to be two cosmonauts in the capsule.

Right: Entry into the suit was via the hinged backpack at the rear. The connectors and tubes for the cooling suit can be seen resting on the base of the hatch opening. The radio is the silver box at the top of the door. The wire aerial runs up and around the top of the backpack and is mounted on a block of foam to prevent interference from the metal of the suit. The battery pack is attached to the base of the door. The lever to secure the door is by the right elbow and the twin rows of seals for the door can be clearly seen. Note the green hue of the two visors when down and also the mouthpiece for drinking water mounted on the inner rim of the visor to the left. The water reservoir is the white rectangle just below the visor.


Both the US and USSR recognised that the lunar explorer would be subject to far greater workloads than previously experienced. Keeping the body cool would be critical, and the air-cooling systems of earlier suits would prove to be inadequate. The solution for both Russian cosmonaut and American astronaut was to be found in a development of a British design of liquid cooling garment originally intended for RAF aircrew. Worn under the pressure suit, the cooling suit comprised a network of PVC tubes that were held close to the skin by an elasticated undergarment resembling long johns. By circulating a liquid through the tubing the body was cooled by direct conduction, virtually eliminating any perspiration. The Soviet garment differed slightly from the US version in that the cooling tubes were extended to the head in a hood arrangement. To enter the suit the cosmonaut grasped the top edge of the rear hatch and slid his legs into the suit. Sitting on the bottom lip of the hatch he connected the two tubes of his cooling garment to those of the backpack, and plugged in his radio headset and bio sensors to the suit radio. Placing his arms in the sleeves, he then slid down into the legs of the suit. In practice this was far easier to do in zero gravity. Once in he would be unable to reach behind him to close the hatch. To do this he pulled on a cable terminated by a small ring on the left side of his fold-out control panel. When closed, lifting a lever at his right hip pulled the door tight against two concentric seals in the rim of the hatch. As the suit built up internal pressure to its operating level of 5.8psi the door seals would inflate and seal the hatch.

Left: The Krechet suit on the ladder of a mock-up lunar lander during testing. A rare glimpse of the pressure suit, usually hidden beneath the thermal cover which, in this instance, is only fitted to the backpack portion of the suit. (NPO/RSC Energia) Above: Cooling suit for the Soviet Krechet 94 moon suit.


Once in, the cosmonaut pulled down on the horizontal bar below the control panel, releasing it from its stowed position and powering it up. The panel displayed levels for battery, cooling water, CO2 and oxygen. A row of buttons along the top controlled the radio and reserve power. Work on the suit was suspended in 1972 and stopped altogether in 1974. Whilst the Russian lunar mission Krechet and Orlan* suits never got to be used for their intended roles, their innovative design represented a seminal moment in spacesuit design. Today, all suits that are designed for use outside the confines of the spacecraft, whether Russian, American, Chinese or European, use this semirigid design. The Krechet suit was a classified secret for over 25 years and very few are known to have survived. There are only 3 suits on public display – two in Russia and one in the USA, standing as silent testament to what might have been.

*- Unlike Apollo, the Soviet spacecraft did not have an internal hatch between the lunar lander and the command module. The cosmonauts would need to perform a short space walk to transfer between the two craft. The second crew member would use a muchsimplified version of the Krechet suit called Orlan. The Orlan suit was not capable of self-contained operation and required an umbilical connector from the spaceship to supply oxygen and electrical power to the suit. At the end of the lunar program, far from being scrapped, the design was constantly developed by Russia and is still in use today. In its current form it is capable of fully self-contained operation, just like the Krechet of 1969.


Above: The only surviving example of the Russian Lunar surface camera. The camera used 35mm film and was designed to be held like a pair of binoculars. The shutter release (the small rod protruding from the base of the camera) was operated by the thumb of the right hand, the three lenses taking one landscape image and a stereo pair of images. The motorized film advance was contained within the film magazine and was powered by the space suit’s backpack via a cable screwed into the rear of the magazine. To aim the camera the cosmonaut used a wire frame viewfinder (not shown). The camera is pictured showing the underside and in the correct orientation for use. (Special Auction Services)

Left: The large grey disc with the white knob is an umbilical and ventilation connector to recharge the suit when stored in the spacecraft. The white oval knob at the side of the control panel is an extendable lever used to break the twin seals of the entry hatch should it become jammed. The two small white knobs near the left sleeve control oxygen supply and suit pressure. Right: Relics of the race to the moon - two prototype control panels for the Russian moon suit.

Was there a Russian moon boot? Of the few surviving Soviet moon suits on display throughout the world, none have boots that would have been suitable for walking on the moon. The boots that they do wear are more of a short, ankleheight shoe. They are broadly similar in design and function to the shoes found on the Apollo A7L suit and, like their U.S counterpart, form part of the pressure garment assembly (PGA). On the U.S suit it is over these shoes that the moon boots would be worn (hence their official NASA title of ‘lunar overshoes’). Whilst both Russian and American PGA shoes have a thick, rigid sole, and both feature aluminum heel restraints (to secure the astronaut or cosmonaut to the floor whilst piloting their lunar lander in low gravity), the U.S sole is attached directly to the pressure suit, whilst the Soviet sole is attached to the uppers of the shoe that also act as part of the thermal cover layer. Insulated with layers of silver Mylar-type foil, the Soviet shoes are attached to the pressure suit by a series of small loops around the top of the shoe. A similar system is used on the U.S suit to attach the thermal cover layer to the boot beneath.

Where the Soviet shoe differs from its U.S counterpart is in the materials used in its construction. Whilst the U.S shoe uses purely synthetic materials, the Russian shoe makes use of thick leather for the sole and soft, perforated leather for the uppers, with the silver insulation being clearly visible through the perforations. Although well protected from the extremes of heat and cold in space, as footwear for walking on the moon the Soviet shoes on their own would have been a disaster. The low cut design would have quickly filled up with the fine, abrasive lunar dust, as would the perforations in the leather. The soft, perforated leather would also have been very vulnerable to damage from sharp rocks and prone to tearing. Clearly these shoes were never intended to be used directly on the moon’s surface without some form of additional protection, and testing at Zvezda would have borne this out.


Discovered amongst piles of documents from Zvezda referring to tests of the Krechet-94 lunar space suit, there is one intriguing reference to what appears to be a moon boot. During the development of the suit the documents stated that, after testing various prototype boots with glued seams, it was recommended that a boot be made using a combination of a cast rubber sole and fabric uppers. The uppers would be fire resistant and, like the outer covering of the suit itself, use a Soviet-developed version of the USA’s Nomex or Betacloth. This proposed design and construction of a Soviet moon boot would appear to be very similar to that of the Apollo lunar overshoe. From these documents it is clear that a moon boot very similar in construction to that of the Apollo boot was produced, albeit only as a prototype for testing. It is not clear whether the lunar program was cancelled before the prototype could be properly developed, but to date no drawings, photos or actual examples of a Soviet moon boot have ever surfaced.

Above: “Zvezda” laboratory conclusion for testing rubber-fabric boots designed for Russian moon spacesuit ”Krechet”, 2 pages, signed by Deputy of KB-1 laboratory Pivovarov, engineer Fetisova, the chief of brigade No.16 Livshitz and leading designer of KB-2 Stoklitsky. Image courtesy of The wording reads: ‘The test took place in laboratory KB-1. A vacuum-thermal test was conducted on the rubber-fabric boots for the “Krechet” moon suit. The purpose: to determine the thermal protection for the sole of the boots. Both the side and the surface of the boot was tested for thermal resistance. The level of thermal currents through the sole became lower than expected during the cold-resistance and heat-resistance tests. The temperature of hermetic insulation of the boot was stable at +15C after 0.5 hours of contact with (a surface of) -180C. After 7 hours the temperature of hermetic insulation of the boot in the area of the heel and toe was stabilized at +20C and +25C. After 4 to 5 hours of the sole being in contact with +150C the temperature of hermetic insulation in the toe area reached +56C to +57C and stayed unchanged for the following 7 hours. The maximum temperature of hermetic insulation in the area of the toe was equal to +43C. During the two tests the hermetic insulation had been damaged in the area of the glue seams at temperature of +60C. To avoid accidents the use of any glue seams for hermetic boots should be forbidden and only cast rubber covers should be used. Taking into account all the tests we came to the following conclusion: The thermal quality of this type of boot provided acceptable levels of temperatures which would allow for a cosmonaut to withstand heat currents during contact with the surface between +150C and -180 to -190C. The following tests were used to make the physical experiments with this type of boot...’




The moon walkers


Neil A. Armstrong (CDR)

Edwin E. Aldrin (LMP)

Charles Conrad, Jr. (CDR)

Alan L. Bean (LMP)

Edgar D. Mitchell (LMP)

Alan B. Shepard, Jr. (CDR)

David R. Scott (CDR)

James B. Irwin (LMP)

John W. Young (CDR)

Charles Duke, Jr. (LMP)

Eugene A. Cernan (CDR)

Dr. Harrison H. Schmitt (LMP)

Right: The boots worn on the moon by Eugene Cernan, commander of Apollo 17 and the last man to walk on the moon. Apollo 17, 1972. Photo by Mark Avino, National Air and Space Museum, Smithsonian Institution (NASM 2008-12210).

With grateful thanks to Bill Ayrey of ILC Dover, LP, Michael Brierton and Nancy H. Pitts of Momentive Performance Materials, Ms. Kate Igoe and Cathleen Lewis of the National Air and Space Museum, Washington, Jon Furley photographer, Mary Ann & John Allen and Graham Boog-Penman of Juice Communications, for their time, generous help and assistance.

Bibliography: GE Silicones Digest Vol.6 Summer/fall 1969 – Silicones on the moon. U.S Space Gear - Lillian D. Kozloski 1994 Smithsonian Institution Press. ISBN 0-87474-459-8 Spacesuits - Amanda Young 2009 Powerhouse Books ISBN 978-1-57687-498-1 US Spacesuits - Kenneth S. Thomas and Harold J. McMann 2006 Praxis Publishing Ltd. ISBN 10:0-387-27919-9 The Soviet Reach for The Moon 2nd edition - Nicholas L. Johnson 1995 Cosmos Books ISBN 1-885609-03-5 Rocket and Space Corporation Energia Apogee Books - 2001 ISBN 1-896522-81-5 Gemini – Steps to the Moon - David J. Shayler Praxis Publishing 2001 ISBN 1-85233-405-3 Illustrated Parts Breakdown Model A7LB Apollo, Skylab & ASTP Space suits - ILC Industries, INC Document number 8819700713C 1973 ILC Space Suits & Related Products William Ayrey, primary Author & Publisher 0000-712731 Rev. A Magnificent Desolation - Buzz Aldrin. 2009 Crown Publishing ISBN 978-0-307-46346-3 Space - celebrating 50 years of human space flight - David Baker 2011 Key Publishing Ltd

The copyright in the material and photographs contained in this publication belongs to the author except where it is stated otherwise. All rights are reserved. No part of this publication may be copied, performed, published, broadcast or adapted, for any medium without the prior written permission of the author - except solely for your own personal and non-commercial use in accordance with the law. The author has made every effort to ensure that all information contained within this publication is correct at the time of publication, to the extent permitted by law. The author shall not be liable to any person for any loss or damage whatsoever, which may arise from any reliance upon, the use of, or any dealings with any of the information contained in this publication. © David Mather 2014

ST31S147-01 silicone rubber ST12G316-01 cloth

ST11D024-01 cloth 11 layers

ST11M282-01 cloth



ST17M042-02 film 11 layers

ST12H327-01 fabric 2 layers ST11M282-01 cloth


Moon Boot  
Moon Boot  

The story of the Apollo lunar overshoe and the race to walk on the moon. Written to accompany a limited edition presentation of 750 soles c...