For a long time, nuclear-powered engines have been discussed for space exploration. Such engines would be more powerful than conventional combustion ones. But due to risks of radiation exposure, unstable reactors and other technological challenges, the idea is yet to materialize. However, a Seattle-based company has come up with an engine design that can mitigate the challenges and help realize the dreams of completing a trip to Mars in just three months.
Ultra Safe Nuclear Technologies (USNC-Tech) has developed a concept design for a Nuclear Thermal Propulsion (NTP) engine. The company claims it is safer and more reliable than previous NTP designs. In addition, it has greater efficiency than a chemical combustion rocket. USNC-Tech came up with the design after receiving funding from NASA.
"Our engine maximizes the use of proven technology, eliminates failure modes of previous NTP concepts, and has a specific impulse more than twice that of chemical systems," USNC-Tech's principal engineer Dr Michael Eades said.
The liquid fuel propellant that is used in the chemical rockets has already reached its theoretical limits. If the same engines are used, it will take around nine months to reach the Red Planet. While many other concepts have been proposed earlier, none of them are practical. Electric propulsion has a low thrust and other concepts are technologically limited including anti-matter rockets.
However, nuclear-powered rockets have always intrigued scientists. Now, UNSC-Tech has proposed a novel approach to achieve that goal. The company is using a Fully Ceramic Micro-encapsulated (FCM) fuel for the reactor.
It is based on High-Assay Low Enriched Uranium (HALEU) which is a reprocessed version of the nuclear fuel. In this case, the uranium that is used in nuclear reactors for power generation is enriched by up to 20 percent. The fuel is then compressed into zirconium carbide coated particles.
That way, the fuel is more efficient and can operate at high temperatures. Hence, the required reactor will be safer and can provide high thrust. More importantly, the fuel can be produced using the current manufacturing plants.
USNC-Tech believes that their NTP design, if developed, could help drastically reduce the exploration time. With such an engine, a crewed Mars mission will take only three months. Besides space exploration, such design can be used for quick orbital logistics.
"Key to USNC-Tech's design is a conscious overlap between terrestrial and space reactor technologies. This allows us to leverage the advancements in nuclear technology and infrastructure from terrestrial systems and apply them to our space reactors," said Dr Paolo Venneri, USNC-Tech's CEO.
With NASA readying a manned mission to Mars by 2024, such design will be useful. At present, NASA is developing the Space Launch System (SLS) which will take humans back to Moon by 2024. On the Moon, a base will be set up for a launchpad from which another rocket to Mars is likely to lift off.
The SLS would be the most powerful rocket ever built. Elon Musk's SpaceX is also building a rocket more capable. Named Starship, it plans to carry a crew to Mars by 2024. However, both the SLS and Starship will use chemical combustion engines that are less efficient than nuclear rockets.