How Nuclear Technology Will Get Us to Mars Faster Than Ever
You can’t get all the way to Mars without fuel – and a lot of it.
Chemical propulsion has been the standard for spaceflight for decades, but if humans are to travel to Mars, they need a propulsion technology much more powerful.
“When you get into needing the level of power it takes to advance our exploration of the Moon and send humans to Mars, the only way to do it is nuclear power,” said Rob Chambers, Director of Commercial Civil Space Strategy and Business Development at Lockheed Martin.
“If you want to be able to explore cost-effectively, be Earth-independent and make going to Mars feasible, you need nuclear systems.”
How Nuclear Energy Systems Work (Hint: They’re Safe)
Although they’re relatively new – nuclear systems for propulsion or electrical power are simple.
Fission-based systems work by splitting low-enriched uranium atoms in a reactor to create heat. Super-cooled hydrogen is flowed into the reactor and the heat from the uranium quickly turns the hydrogen into a very hot, pressurized gas.
In nuclear thermal propulsion (NTP), the super-hot pressurized hydrogen is funneled out a nozzle to create a powerful thrust. The mechanics of an NTP engine are much simpler and vastly more efficient than chemical propellent engines.
In fission surface power systems, the heat from the splitting of uranium atoms is converted to electricity. These systems can produce at least 40 kilowatts of power and can operate on permanently shadowed regions of the Moon.
One of the mechanics that makes NTP safe is simply that the mechanics wouldn’t happen on Earth.
A traditional chemical propulsion launch vehicle would lift a spacecraft off Earth’s surface and navigate it to a safe Earth orbit far out of the Earth’s atmosphere. Once in this orbit, the nuclear reactor would be turned on, and the fission process would start. This makes handling and launching a reactor with the high assay low enriched uranium (HALEU) fuel very safe.
Defining the level of ground testing that’s needed to prove safe, effective operations in space is part of Lockheed Martin’s current efforts, too.
“Ground testing helps us understand what the expected behavior and limitations of the nuclear reactor are and how we expect it to respond and interact with the control systems that we’re developing,” said John Bendle, Senior Manager, Strategy and Business Development, Human Space Exploration, Lockheed Martin.
Why Nuclear Thermal Propulsion?
In short: speed, efficiency and reusability.
NTP will enable faster space travel than ever before.
Increased speed from NTP means benefits like longer launch windows, less crew exposure to cosmic radiation in space and satellites and robotic spacecraft getting to their destinations quicker or with much higher mass.
The speed of NTP comes from its high-efficiency thrust—upwards of two times more efficient than conventional propulsion systems.
“It could take a hundred launches to get humans to Mars on a chemical propulsion system, but we can get it down to five with a nuclear thermal propulsion system,” said Chambers.
NTP’s efficiency can also enable more abort options during missions.
Other benefits include maximum reusability and extensibility to other missions. NTP allows the use of fewer refuelers than other systems – making it an environmentally cleaner, more efficient way to fuel.
“If we want to get serious about deep space exploration, a reusable nuclear system is a cleaner, more efficient way to achieve our goals,” said Bendle. “NTP will enable us to extend our exploration beyond the Moon more quickly than other alternatives might.”
An Economy on the Moon and Other Possibilities
Making safe nuclear systems a reality is within our reach – and with it, so are massive changes in the way we do space exploration.
“Surface fission power would mean a stable, Earth-independent power source on the Moon and Mars,” said Lisa May, Principal Engineer and Next Gen Strategy Lead, Lockheed Martin.
High-power fission-based systems on the Moon would enable splitting lunar water into hydrogen that can be used for propellant, and oxygen for astronauts to breathe.
“We envision a water-based economy on the Moon, where what we need to fuel space travel can be extracted, traded and utilized on the Moon,” said Chambers.
Time to Turn Vision into Reality
Lockheed Martin’s space nuclear systems work includes three current contracts – a partnership with BWXT Technologies on both nuclear thermal reactor and fission surface power concepts for NASA and the Department of Energy, and a contract with the Defense Advanced Research Projects Agency to develop a spacecraft concept design with NTP capability.
While nuclear systems are an emerging field, Lockheed Martin has a long history and expertise in nuclear controls, having supported instrumentation and controls for both terrestrial power plants and Naval nuclear reactors. Lockheed Martin’s expertise in avionics, mission control and integration give us leverage.
“Our discriminator also comes from our deep space exploration heritage, which requires the ability to do high-technology, first-of-a-kind missions,” said May. “We’ve also invested heavily in cryogenic hydrogen storage and transfer, as well as the overall nuclear reactor controls.”
The company also built the radioisotope thermoelectric generators for NASA planetary missions such as Viking, Pioneer, Voyager, Apollo, Cassini and New Horizons.