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By Tanveer Ahmed :
Morgan State University-led research aims to create compact radiovoltaic systems for space, defence and remote operations
The US Defense Advanced Research Projects Agency (DARPA) has awarded Morgan State University a $3.37 million research contract to develop next-generation radiovoltaic technology capable of generating electricity continuously for decades without requiring refuelling.
The project, known as SYMPHONEE (Strontium-Yttrium Multi-junction PIN-based High-Density Output Nano-system for Extreme Environments), is part of DARPA’s broader Rads to Watts initiative. The programme seeks to develop compact, high-density power sources for applications where replacing or recharging conventional batteries is impractical.
Unlike traditional batteries, radiovoltaic devices generate electricity by converting energy released during radioactive decay directly into electrical power. The principle is similar to how solar panels convert sunlight into electricity, but radiovoltaic systems rely on radioactive particles instead of light, allowing them to operate continuously regardless of weather or lighting conditions.
Professor Michael Spencer, the project’s technical lead at Morgan State University, said the research team is working to expand the capabilities of radiovoltaic technology.
“Our team is pushing the boundaries of radiovoltaic technology, developing high-power, long-life systems that were not previously achievable. By integrating advanced materials, device engineering and nuclear science, we are laying the foundation for a new generation of persistent power systems for extreme environments.”
Using recycled nuclear waste as an energy source
The prototype combines ultra-thin semiconductor materials with Strontium-90, a beta-emitting radioactive isotope commonly recovered from spent nuclear fuel and legacy Cold War nuclear waste.
Rather than producing heat like conventional radioisotope generators used on deep-space spacecraft, the new system converts radiation directly into electricity through semiconductor devices. Researchers believe this approach could significantly improve power density while reducing the size and weight of future energy systems.
The project aims to achieve an output of more than 10 watts per kilogram, a milestone that could make the technology practical for long-duration missions in environments where conventional batteries degrade or cannot be replaced.
Strontium-90 also offers advantages over plutonium-based power sources that have historically been used in space exploration. It is considered easier to handle under controlled conditions and can be recovered from existing nuclear waste, potentially giving new value to material that would otherwise require long-term storage.
According to the US Department of Energy, the United States stores more than 100,000 metric tons of spent nuclear fuel across dozens of reactor sites, creating growing interest in technologies that can safely recycle radioactive materials for beneficial applications.
Industry and national laboratory collaboration
Morgan State University is leading the programme in collaboration with several government and industry partners, including Northrop Grumman, Pacific Northwest National Laboratory (PNNL), Project Omega, Applied Research Associates, and Widetronix.
Northrop Grumman is contributing expertise in advanced microelectronics, radiation-resistant system design and artificial intelligence-driven modelling to accelerate device development. Meanwhile, PNNL will conduct testing and characterisation of nuclear materials under demanding operating conditions.
According to Morgan State University, the project is designed to deliver a major increase in power density while maintaining long operational lifetimes.
Early computer simulations indicate the technology could exceed the programme’s performance goals, potentially enabling entirely new classes of autonomous systems that require reliable electricity for years or even decades without maintenance.
Prototype expected in 2027
Researchers expect to produce an initial prototype by early 2027, after completing laboratory validation and progressively more realistic environmental testing.
Several technical challenges remain before the technology can be deployed. These include improving the efficiency of radiation-to-electricity conversion, ensuring semiconductor materials remain stable after decades of radiation exposure, and establishing robust safety standards for handling and deploying radiovoltaic devices.
Scientists must also demonstrate that the systems can operate reliably for up to 30 years, making them suitable for long-term missions in harsh environments.
Potential applications beyond defence
Although DARPA is funding the programme with defence objectives in mind, radiovoltaic technology could have broader commercial and scientific uses if successfully developed.
Potential applications include powering satellites that operate for decades without servicing, underwater monitoring equipment, Arctic and Antarctic research stations, autonomous environmental sensors, and infrastructure located in remote regions where battery replacement is costly or impossible.
The technology could also benefit future space exploration by providing lightweight, maintenance-free power systems for lunar and planetary missions, complementing existing radioisotope power technologies already used by agencies such as NASA.
As military and civilian organisations increasingly deploy autonomous systems in remote and inaccessible environments, demand is growing for energy sources that combine compact size, long operational life and minimal maintenance. DARPA’s investment in the SYMPHONEE programme reflects a broader effort to develop power technologies capable of supporting those next-generation missions.
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