Updated standards for explosive devices and other breakthroughs
By John F. Zevenbergen|December 2024
The Energetic Components and Systems Technical Committee provides a forum for the dissemination of information about propellant and explosive-based systems for applications ranging from aircraft to space vehicles.
In January, researchers from Purdue University in Indiana presented at AIAA’s SciTech Forum their study on how multi-material 3D printing changes the mechanical properties of propellant surrogates with a new ultraviolet-curable binder. After controlling for time and spatially varying UV irradiance, they concluded that the specimens did preferentially break at the interface, which is promising for producing multi-material structures.
Also in January, Karman Space & Defense of California completed the first full-system test of its descent parachute mortar for NASA’s Dragonfly mission to Titan. Karman leveraged decades of experience in pyrotechnic-based mortar systems for human and exploratory spacecraft to address the challenges posed by Titan’s harsh conditions. Among them, the Dragonfly quadcopter must operate within surface pressure 1.5 times that of Earth’s and survive methane clouds and rain in temperatures below minus 150 degrees Celsius. These conditions also make it more challenging to deploy and operate the parachute that controls Dragonfly’s initial descent toward Titan’s surface. The test campaign included simulating thermal, pressure and dynamic environments that Dragonfly would experience during launch, space flight and on Titan’s surface. As needed, engineers conducted proprietary analyses with models based on results of previous missions to verify performance of the parachute motor, which is considered mission-critical hardware. Design updates based on refined mission parameters were completed in the middle of the year, and testing is ongoing.
In July, researchers from Purdue University presented research on energetic processing methods at the International Pyrotechnic Society Seminar. The researchers observed the flow of surrogate powders via high-speed camera as a function of motor voltage and nozzle size. Understanding the role these factors play on the dynamics of powder flow is critical to ensure high-precision deposition. They also developed and characterized a new method for making a molding powder, with 90% sugar by weight using hydroxyl-terminated polybutadiene. This new processing approach could be a much faster method to tune the properties of plastic-bonded explosives.
In January, the Energetic Components and Systems Technical Committee completed updates to its standard, “Criteria for Explosive Systems and Devices on Space and Launch Vehicles.” Published in late 2023, the document established criteria for engineers and contractual professionals for design, manufacture and performance certification of explosive systems and explosive devices commonly used on space vehicles and on uncrewed launch systems. The requirements in the standard are intended to serve as a universal set of tools for explosive device manufacturers and application specialists during all phases of development and certification. The committee initiated the effort in 2020 to update its previously published standards in 2005, 2016 and 2018.
Time is a core variable when gathering data, yet the influence of history is not considered when analyzing temperature data from pyrometry, information about an object’s temperature derived from the radiation it emits. In May, researchers from the Naval Air Warfare Center Weapons Division and Texas Tech University developed a new method of analyzing pyrometry data to assist in studying energy conversion processes in reactive systems. Their method, published in the International Journal of Heat and Mass Transfer in August, introduced a specific way of analyzing a sequence of data points collected over a time interval rather than analyzing snapshots of data and reeling them together. What sets this time series approach apart from traditional techniques is that the analysis distinguishes patterns and dependencies otherwise masked. Time series analysis is commonly used to predict the stock market and forecast weather patterns. With advances in sensor technology and the ability to capture gigabytes of data, the time is right to think differently about approaches to interpreting thermodynamic data.
Contributors: Igor Altman, Thomas Blachowski, Monique McClain, Michelle Pantoya and Chris Stessing
