A recently patented invention could help Department of the Air Force (DAF) satellites maintain appropriate temperature while orbiting Earth.
Mr. Jon Allison, a researcher at the Air Force Research Laboratory (AFRL) Space Vehicles Directorate (RV), recently received a patent from the U.S. Patent and Trademark Office for “Bidirectional Regulating Heat Pipe Network” technology. This technology is the latest in a series of innovations that have led to Mr. Allison being awarded multiple patents. The latest invention, according to Mr. Allison, can help U.S. Space Force (USSF) satellites maintain proper temperature in the extremes of space.
The invention in question is a network of heat pipes designed to provide thermal regulation, which refers to ensuring that a given item becomes neither too hot nor too cold. Heat pipes are closed metal tubes containing fluid. They use capillary action – the ability of liquid to flow in narrow spaces without the application of external forces – to regulate the temperature of the item whose thermal condition they are controlling. An individual heat pipe has a hot interface at one end and a cold interface at the other. The fluid inside the pipe evaporates at the hot interface, absorbing heat. The fluid condenses at the cold interface, releasing heat. Heat pipes can be used to either heat up or cool down the primary object whose thermal condition they are controlling. Different types of heat pipes can either regulate outbound heat flow or regulate inbound heat flow, but a single heat pipe cannot do both.
Heat pipes already have a wide variety of contemporary applications. For example, they are built into modern electronic devices like laptop computers and desktop computers to help the devices remain at the proper temperature while operating. These devices generate heat while turned on, and heat pipes transfer heat away from the item to prevent it from overheating.
Like computers and smartphones, satellites generate heat. However, they are also regularly subjected to temperature extremes greatly exceeding those experienced by electronics on the Earth’s surface. Satellites operate in the vacuum of space and are often exposed to extremely cold temperatures. However, depending on their proximity to the sun, they sometimes also get very hot. According to Mr. Allison, this phenomenon creates a “Goldilocks problem,” since satellites need to remain at the “just right” temperature even when subjected to both very hot and very cold stimuli as they move within their orbits. Existing heat pipe designs, though, regulate heat transfer in only one direction. The USSF needs its satellites to be able to regulate heat in both directions, and Mr. Allison conducted his work in response to this stated desire.
Mr. Allison’s invention involves connecting heat pipes in a new and innovative way that allows them to help the surrounding device either absorb heat or release it as needed. This novel network design permits a single series of heat pipes to heat or cool an item. If built into a satellite, then, the series of pipes will keep the satellite warm when the temperature around the satellite is far below freezing. However, the pipes will help the satellite remain cool when it is subjected to the severe heat of the sun’s energy. According to Mr. Allison, the network design creates a phenomenon greater than the sum of its individual parts by efficiently and effectively keeping satellites at the proper temperature.
As Mr. Allison noted, the initial design shows significant promise, but there is still more work to be done in conjunction with industry partners to test physical models within thermal vacuums to demonstrate that they work as intended. Mr. Allison looks forward to the opportunity to work with contractor partners to investigate the functionality of the technology in practice.
According to Mr. Allison, this invention provides a tangible example of AFRL’s ability to address a long-term problem in a relatively low-resource-consumption manner. As he noted, military financial investments need to balance short-term acquisitions of existing technology with long-term research and development of new solutions, and AFRL is well positioned to address the long-term component of that balance. Indeed, successful maturation of this innovation could help the United States achieve and maintain space superiority.
Mr. Allison’s patent application was facilitated by RV’s Office of Research and Technology Application (ORTA). DAF ORTAs promote technology transfer processes and protect DAF’s interests in discoveries achieved in DAF research laboratories. DAF ORTAs work with DAF scientists and engineers to navigate the patent application and issuance process, ensuring that DAF’s intellectual property interests are preserved when DAF-originated inventions are transferred outside of government for further development. Mr. Allison is already working to identify potential partners that could enhance technology, which would generate significantly augmented capabilities.
DAF ORTAs coordinate their activities with the DAF Technology Transfer and Transition (T3) Program Office. The DAFT3 Program Office trains and oversees individual ORTAs and performs ORTA functions for DAF laboratories without a designated ORTA.
United States Patent and Trademark Office Patent #12,565,338
About AFRL
The Air Force Research Laboratory, or AFRL, is the primary scientific research and development center for the Department of the Air Force. AFRL plays an integral role in leading the discovery, development, and integration of affordable warfighting technologies for our air, space, and cyberspace forces. With a workforce spanning across nine technology areas and 40 other operations around the globe, AFRL provides a diverse portfolio of science and technology ranging from fundamental to advanced research and technology development. For more information, visit www.afresearchlab.com.