How can fission-powered propulsion help advance deep space exploration, specifically to the outer planets like Jupiter, Saturn, Uranus, and Neptune? This is what a recent study presented at the 56th Lunar and Planetary Science Conference (LPSC) hopes to address as a pair of researchers from India investigated the financial, logistical, and reliability of using fission power for future deep space missions. This study has the potential to help scientists, engineers, and future astronauts develop next-generation technologies as humanity continues to expand its presence in space.
Here, Universe Today discusses this incredible research with Malaya Kumar Biswal, who is the Founder & CEO of Acceleron Aerospace in Bangalore, India, regarding the motivation behind the study, significant takeaways, and exploring other star systems. Therefore, what was the motivation behind the study?
“The primary motivation for this study was the growing realization that our current propulsion and power systems—particularly chemical and solar-based—are not sufficient for long-duration or deep space missions,” Biswal tells Universe Today. “As we push the boundaries of exploration toward Mars, the outer planets, and even interstellar space, we need power systems that are not only reliable but also capable of delivering sustained energy for decades. Nuclear power, especially fission-based systems, offers a solution with its high energy density and independence from sunlight. Our aim was to explore how these technologies could transform the way we plan, power, and execute missions beyond Earth orbit enabling true multiplanetary and interstellar missions.”
For the study, the researchers evaluated a myriad of characteristics regarding how fission-powered propulsion systems could successfully advance deep space exploration, including power systems, key advantages, notable developments, potential applications, and limitations. This involved in-depth analyses into radioisotope electric propulsion, fission electric propulsion, high-power output and needs, long-duration missions, NASA’s KRUSTY (Kilowatt Reactor Using Stirling Technology) proposed concept, multiplanet exploration, Moon and Mars crewed missions, and comparing to traditional systems.
In the end, the researchers referred to fission power propulsion as a “game-changer” offering a myriad of benefits and advances beyond current propulsion technologies with very few limitations, specifically radiation shielding and mass. But what are the most significant takeaways from this study?
Biswal tells Universe Today, “First, fission power systems offer significantly higher and more consistent power output than traditional sources, which is critical for both propulsion and life-support systems on long missions. Second, these systems can reduce transit time, support larger payloads, and operate in environments where solar power simply isn’t viable—such as deep space or shadowed planetary surfaces. Third, while the technology shows incredible promise, it also comes with challenges, particularly in radiation shielding, safety protocols, and system mass. However, ongoing developments like NASA’s Kilopower project show that we’re moving steadily toward making this a practical reality.”
The researchers discuss in-depth how fission propulsion could be used to explore the entire solar system, all the way out to the Kuiper Belt, which begins at the inner orbit of Neptune at approximately 30 astronomical units (AU) and extends as far as 50 AU, with 1 AU being the distance from the Sun to the Earth. For context, the AU distance to Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto are 0.39, 0.72, 1.52, 5.20, 9.54, 19.22, and 30.06, and 39.5, respectively.
The researchers note these travel distances are possible due to fission propulsion being able to function for decades, opening doors to expanding humanity’s presence well beyond Earth, possibly to the moons of the giant planets. While this study doesn’t mention traveling beyond the solar system and into interstellar space, other studies have proposed sending spacecraft to our nearest star, Proxima Centauri. Therefore, could nuclear-powered propulsion be used to explore other star systems, specifically Proxima Centauri?
Biswal tells Universe Today, “Exploring another star system like Proxima Centauri is a monumental challenge, but nuclear propulsion is one of the few technologies that could make it conceivable within this century. Although reaching Proxima Centauri, which is over 4 light-years away, would still require travel times of several decades to centuries with current technology, nuclear-powered propulsion—especially when combined with electric or ion propulsion systems—could drastically improve our reach and reduce mission duration compared to conventional methods.”
Biswal continues, “For such interstellar missions, high-thrust nuclear thermal propulsion could be used to exit the solar system efficiently, followed by long-duration electric propulsion powered by nuclear reactors to maintain velocity. In theory, these systems could enable probe missions that might one day send back data from nearby exoplanets. While we’re not there yet, this study forms part of the groundwork needed to seriously consider such possibilities in the future.”
This study comes as these same researchers also presented a study at the 56th LPSC proposing the use of a Human-Crewed Interplanetary Transport Architecture (HUCITAR) for exploring Mars and the dwarf planet Ceres, which is also the largest planetary body on the Main Asteroid Belt with evidence that it once contained a subsurface salty liquid water ocean. This HUCITAR study builds on a 2021 study and 2022 study they presented at the AIAA SciTech Forum that also discussed human exploration of Mars and Ceres. As humanity continues to expand beyond Earth and into the cosmos, these studies could provide the framework for future exploration initiatives, enabling humans to reach distant worlds and establish permanent settlements both within and beyond the solar system in just a few generations.
Biswal tells Universe Today, “Our proposed architecture makes a strong case for Nuclear Electric Propulsion (NEP) and Nuclear Thermal Propulsion (NTP) as essential enablers of reduced transit time, increased payload capacity, and mission redundancy. In addition to propulsion, our studies examine mission design in detail, including trajectory optimization, cost models, safety protocols, power generation using RTGs [Radioisotope thermoelectric generator] and fission reactors, and astronaut health considerations for long-duration exposure.”
Biswal continues, “If there's one key message we want to leave with readers, it's that nuclear-powered systems are not just a distant dream—they are rapidly becoming a necessity for meaningful exploration beyond low Earth orbit. At Acceleron Aerospace, we're committed to providing the foundational research, technologies, and mission concepts needed to make this vision achievable, starting with Mars and Ceres, and eventually extending to the outer solar system.”
How will fission-powered propulsion help advance deep space missions in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
