Tomorrow, as you undoubtedly know, is the 50th anniversary of the moon walk. On July 20, 1969, Apollo 11 astronauts Neil Armstrong and Edwin E. “Buzz” Aldrin Jr. became the first humans to set foot on the moon. It was the crowning achievement of a goal first articulated by President John Kennedy in 1961. One of the most eloquent statements about the event’s import came from Wernher von Braun, who said this on the eve of the Apollo 11 liftoff: “What we will have attained when Neil Armstrong steps down upon the moon is a completely new step in the evolution of man. For the first time, life will leave its planetary cradle, and the ultimate destiny of man will no longer be confined to these familiar continents that we have known so long.” It’s somewhat ironic that the same man who developed missiles for Hitler in Nazi Germany could craft such an uplifting observation, but I digress, doubly so because what I really want to write about is the role that plastics have played—and continue to play—in space travel.
Craftech Industries, a privately owned contract manufacturer in Hudson, NY, which offers injection molding, mold making and CNC machining services, published a succinct overview of how plastics have advanced space exploration on its website. “Plastic materials have played a vital role throughout the history of space flight, allowing astronauts to view their surroundings, breathe oxygen and travel comfortably in orbit around the Earth, or on the way to the moon,” notes the company. The article goes on to explain how the versatility and functionality of plastic materials enabled the fabrication of robust helmets and visors, comfortable seating and lighter spacecraft.
Clarity of vision
A paper on the Apollo missions on the NASA website includes a chapter that describes the composition of the extravehicular mobility unit (EMU), or space suit in layman’s terms, that was used in the first lunar landing. The pressure helmet assembly that was part of the EMU was designed to withstand the harsh environment of space but also to provide astronauts with clear visibility of their surroundings.
Since transparency and durability were desired properties in the helmet assembly, it will come as no surprise to plastics engineers that polycarbonate was the chosen material. Specifically, writes NASA, “the helmet was made by a special heat forming process from high-optical-quality polycarbonate plastic.” The paper also notes that a synthetic elastomer foam vent pad was bonded to the back of the helmet shell to provide a headrest, and to act as a ventilation flow manifold for directing the flow of gas to the oral-nasal area. “This flow caused an efficient exhaust of carbon dioxide from the nasal area through the torso neck opening,” write the authors of the paper.
The visor assembly furnished visual, thermal and mechanical protection to the crewman's helmet and head. The article goes on to explain the multifunctional nature of the assembly, made possible by polymer science.
The visor assembly was “composed of a plastic shell, three eyeshades, and two visors. The outer, or sun visor was made of high-temperature polysulfone plastic. The inner, or protective, visor was made of ultraviolet stabilized polycarbonate plastic. The outer visor filtered visible light and rejected a significant amount of ultraviolet and infrared rays,” notes the article, while “the inner visor filtered ultraviolet rays, rejected infrared and, in combination with the sun visor and pressure helmet, formed an effective thermal barrier. The two visors in combination with the helmet protected the crew member from micrometeoroid damage and from damage in the event of falling on the lunar surface.”
A rearguard action
Protecting the head is critical but, like the all-American road trip, space travel also can be rough on the rump—you want your vehicle to be equipped with comfortable seats. To make the journey tolerable and blunt the impact of landings, NASA developed temper foam, which has since migrated into mattresses under the memory foam monicker. “This open cell polyurethane-silicone plastic made it easier for astronauts to travel to and from space without getting injured or feeling uncomfortable upon re-entry,” writes Craftech.
Before design engineers applied lightweighting technology to increase fuel efficiency in automobiles and aircraft, they honed their lightweighting chops designing spacecraft. As the Craftech article notes, lighter materials make it easier and more efficient to get rockets off the ground. They also allow a reduction in the amount of fuel required for the journey. Carrying less of the highly volatile liquid makes the mission a little safer for astronauts.
The monetary and safety benefits yielded by plastics are hard to ignore, writes Craftech, which is why NASA and other space agencies have leveraged plastics to the hilt. And that continues to this day.
In February 2019, the first integrated recycler and 3D printer, the Refabricator, was installed in the International Space Station. It converts plastic products into feedstock, which it uses to 3D print new products, all within a single unit. “The Refabricator is key in demonstrating a sustainable model to fabricate, recycle and reuse parts and waste materials on extended space exploration missions,” says Niki Werkheiser, Manager of In-Space Manufacturing at NASA’s Marshall Space Flight Center in Huntsville, AL.
By the way, if you are interested in taking a deeper dive into the history of space travel, sister brand Design News is celebrating the 50th anniversary of Apollo 11 with a week of special coverage. Multiple articles cover everything from a day-by-day recap of the Apollo mission to profiles of some of the prominent engineers behind the program. It’s well worth your time!
Image of Apollo extravehicular mobility unit courtesy NASA.