The Air Force Research Laboratory’s rocket propulsion division at Edwards AFB, Calif., is using a new piece of equipment, a Split-Hopkinson Pressure Bar system–known as a Kolsky bar–to aid eventually in the design of more resilient satellites and rocket motors.
The Kolsky bar measures high strain rates and helps analyze materials under such stress, AFRL said.
“This system will give AFRL a new and unprecedented capability to test and gather data from any solid propellant we can manufacture,” Timothy Miller, a senior materials research engineer in AFRL’s propellant branch, said in an Aug. 30 statement. “AFRL plans to use the system to test both propellant and space-bound materials at high-strain rates so that structural models can be developed that will predict behavior, especially failure, in real-world conditions.”
The Kolsky bar, installed at AFRL’s on-site chemistry lab at Edwards AFB, tests solid propellant at strain rates that match threats from bullet impact, fragment impact, and “sympathetic detonations” in which an undesired missile detonation causes a shock wave that explodes a nearby missile.
“Ultimately, these models will aid in designing improved rocket motors and satellites,” per AFRL. “This new capability will also help AFRL to investigate other occurrences such as space debris impact, which can disable satellites, and in some cases, can compromise structures and render them useless.”
Miller said that “every solid rocket motor tested has the potential for defects that cannot be seen during manufacturing, and even in the absence of defects, can be susceptible to damage due to external events.”
“Data from high strain rate tests is key to preventing [unintentional damage] and AFRL will use this system to quantify material properties related to all rocket motors, including those made with advanced manufacturing processes such as Resodyn mixing and additive manufacturing,” he said.
U.S. Space Force (USSF) Chief of Space Operations Gen. John “Jay” Raymond has said that space systems’ resilience is a top priority and that USSF must “identify a future force design underpinned by world class analysis to balance performance, cost and resilience” (Defense Daily, Aug. 24).