The Canadian Story of the Apollo Lunar Module Landing Legs

Héroux-Devtek fabricated the lunar module landing legs for the Apollo 11 mission. Credit: Héroux-Devtek Inc.

In the early 1960s, a Canadian company suddenly found itself at the forefront of the American effort to put United States astronauts on the moon. On the back of a contract worth the equivalent of $2 million today, Héroux (today’s Héroux-Devtek) beat out several competing American contractors to manufacture the lunar module’s landing legs.

The challenge was considerable. Héroux received the contract years before the first robotic spacecraft softly landed on the moon in 1966. Yet the company was tasked with a design with five main goals, according to Aero Montreal (Montreal’s aerospace sector group): bring the vehicle to rest, prevent toppling, absorb the landing impact energy, limit the loads on the spacecraft structure, and create a stable launch platform so that astronauts could launch again for the journey home.

Héroux-Devtek of Longueuil, Quebec, fabricated the lunar module landing legs for the Apollo 11 mission. Credit: Héroux-Devtek.
Héroux-Devtek of Longueuil, Quebec, fabricated the lunar module
landing legs for the Apollo 11 mission. Credit: Héroux-Devtek.

As many students of space history know, the prime contractor for the lunar module was Grumman (today’s Northrop Grumman), who won a competitive process among nine bids submitted to NASA in September 1962. Contemporary news reports suggest that Héroux’s Lionel Whyte subsequently tried reaching out to a contact at Grumman to express interest in participating, but at first they were rebuffed because they were a non-American firm, said Rénald Fortier, a curator in aviation history at the Canada Aviation and Space Museum in Ottawa, in a SpaceQ interview.

“Very soon,” Fortier added, “That day or the day afterwards – a subcontractor working on the lunar module contacted Whyte or Héroux saying, ‘We have a problem. We are trying to work with this steel alloy, which is good – but difficult to work with. Can you help us?’ “

Apollo landing gear thermal protection. Credit: NASA.
Canadian built Apollo lunar module landing gear. Credit: NASA.

The subcontractor was Belgian, so Whyte went back to his contact and tried again. The contact did a little checking around and confirmed that Héroux could participate, so it sent in a bid for the lunar landing gear (which made sense since Héroux was known for landing gears.) Turns out Héroux’s offer was the best among 16 competing companies, the rest of them American, Fortier said. They got the contract in 1965; although few employees knew at the time of the ultimate destination for the legs, word quickly got out as they worked to meet their 1967 deadline, according to a blog post Fortier wrote.

The module was originally envisoned as a closed environment with big glass windows, seats and smooth sides. Due to weight requirements, the seats were removed and the windows greatly reduced to little more than portholes. Every spare ounce was shaved off to save on weight for the Saturn V rocket. This complicated process put the lunar module behind schedule, although it still was ready in time for President John F. Kennedy’s stated deadline of landing a person on the moon before the end of the decade.

Astronaut Buzz Aldrin stands next to the landing gear of the lunar module built in Montreal.
Astronaut Buzz Aldrin stands next to the landing gear of the lunar module built in Montreal. Credit: NASA.

The landing gear development included extensive tests of the aluminum honeycomb energy absorbers and the double-cylinder strut bearings to make sure they could handle the weight and stress of landing, according to NASA. There were many things to manage. The astronauts were instructed to avoid steep slopes (of more than 12 degrees) so that the LM’s engine, which took several seconds to turn off completely, wouldn’t topple over the spacecraft. Thermal insulation was beefed up out of a concern that the landing gear was exposed to much higher heating rates than anticipated. The struts were also carefully examined to remove any source of friction, since space mechanics are hard to come by 385,000 km from Earth.

Apollo 11 Lunar lander stamp
Apollo 11 Lunar lander stamp. Credit: Canada Post.

While lunar module development lagged overall, the landing legs (as far as NASA documents show) arrived on time. Their result was strong: six lunar modules safely landed on the surface – and the lunar legs performed quite well in that process. With all touchdown velocities within design limits, NASA said, the LM made a stable landing on each occasion. The program delays resulting from extra leg testing also appear to have been minimal – Fortier said there was once a concern about a component being 0.05 millimeters out of place, but Héroux “eventually got it right.” To be fair to Héroux, he added, these are tolerances that are much more strict than in their other industries that came before space.

NASA also has praise for the landing gear. “At no time did the availability of landing-gear hardware jeopardize the Apollo program schedule,” NASA’s William F. Rogers said in a 1973 technical briefing posted on the agency’s website. “The problems were solved by various means, some by hardware changes and some by criteria changes when such changes had a rational basis. It is concluded that the landing gear met the Apollo design requirements and that development problems were solved before flight.”

Héroux’s contributions were recently honoured in a Canada Post stamp commemorating the 50th anniversary of the Apollo 11 landing.”The Canadian-made landing gear remains on the moon to this day,” pointed out Canada Post.

Correction: The correct measurement for the out of place component was 0.05 millimeters, not 500 millimeters.

Apollo lunar module landing gear

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Apollo lunar module structures handout

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Apollo experience report – lunar module landing gear subsystem

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About Elizabeth Howell

Elizabeth Howell
Canadian space and science reporter, researcher and consultant. I also am pursuing a Ph.D. at the University of North Dakota.