On Oct. 4, 1957, a polished-metal sphere 2 feet in diameter with four antennae was launched by the Soviet Union into a low elliptical Earth orbit. It was called Sputnik I, and it became the planet’s first artificial satellite. This diminutive satellite broadcast its radio pulses for three weeks before its batteries went dead, but it orbited planet Earth for about three months before its decaying trajectory brought it back to burn up upon atmospheric re-entry.
I am old enough to remember the excitement that Sputnik I’s launch generated. With the global excitement (and headlines) caused by Sputnik I passing above us every 90 minutes, however, came the realization that the United States lost a big race in the Cold War with the Soviets. What was a time of scientific elation and political victory in the USSR became a feeling of gloom in this country because Americans could do nothing but watch the satellite orbit above.
The space race was on! After a series of failures and booster rockets exploding on their launchpads, the U.S. finally got it together enough to send satellites successfully and reliably into orbit. In what became a barometer of Cold War one-upmanship, the Americans and Soviets continued with their manned space exploration programs. Again, the Soviets were first by sending Yuri Gagarin (a foundry worker before joining the Soviet Air Force) as the first human in space. In April 1961, he flew Vostok I for one orbit around the Earth and was brought back safely. The U.S. countered with its Mercury, Gemini and Apollo manned space-flight programs, which eventually landed men on the moon.
Flexing Perseverance’s Robotic Arm. This set of images shows parts of the robotic arm on NASA’s Perseverance rover flexing and turning during its first checkout after landing on Mars.
Much has happened since then, and space travelers from many countries have worked together in outer space. As an observer of the space race since childhood, my interest in space technology continues to this day. Even so, I took no notice when the Perseverance rover was successfully launched on an Atlas V booster from Cape Canaveral Air Force station in Florida on July 30, 2020. It took seven months to get the rover to Mars, but Perseverance was spectacularly lowered softly onto the planet’s surface on Feb. 18, 2021.
The mission of Perseverance – Percy for short – is to explore the Mars crater Jezero and, in a broader sense, pick up where its predecessor, Curiosity, left off. The ultimate goals are to explore Martian geology seeking environments that might have at one time supported life; seek evidence of life; and take other planetary and atmospheric measurements.
The car-sized Percy is an upgraded design from Curiosity. It includes seven primary payload instruments, 19 cameras and two microphones. The rover is also carrying the mini-helicopter Ingenuity, an experimental aircraft that will attempt the first powered flight on another planet.
As I read about Percy on NASA’s website, I came across a process covered in this issue of FORGE – additive manufacturing (AM), or 3D printing. NASA, interested in testing the reliability and performance of AM parts, sent its first 3D-printed part to Mars on the rover Curiosity. They upped the ante on Perseverance, which has 11 3D-printed parts on board. According to Andre Pate, the group lead for AM at NASA’s Jet Propulsion Laboratory, AM parts on Percy were used as “secondary structures,” or parts that would not jeopardize the mission if they did not work. Pate said, “Flying these parts to Mars is a huge milestone that opens the door a little more for additive manufacturing in the space industry.”
The stunning images of Martian landscape sent back by Percy got me wondering as to how many forged products were used in the design of the rover. After some Internet searching, I learned that Scot Forge was involved in the development of the wheels used on the Curiosity vehicle under contract to NASA’s Jet Propulsion Lab. They were also commissioned to improve the wheels for Perseverance. There is a short video on how Percy’s wheels were made on the company’s website.
Quoting from the video: “Using advanced proprietary forging and heat-treating techniques, Scot Forge re-engineered the Mars 2020 rover wheels to be substantially stronger, more durable and better protected from damage caused by the rough Martian terrain.”
Congratulations to Scot Forge for their achievement in support of planetary exploration – and their wheel-print on Mars. If other readers of this column have additional stories to tell about forgings on space vehicles, I would appreciate hearing them.