NASA and DARPA have recently partnered with aerospace and defense company Lockheed Martin to develop a spacecraft equipped with a nuclear thermal rocket engine. This ambitious initiative, known as the Demonstration Rocket for Agile Cislunar Operations (DRACO), aims to showcase the capabilities of nuclear thermal propulsion (NTP) by no later than 2027, with the ultimate goal of enabling future Mars missions.
Compared to chemically propelled rockets, NTP offers several advantages. One key advantage is its significantly higher efficiency, with studies showing that NTP can be two to five times more efficient. This increased efficiency allows spacecraft to travel faster and cover greater distances with greater agility. Additionally, the reduced propellant needs of NTP systems free up valuable space on the spacecraft, enabling more room for storing scientific equipment and other essential supplies. The flexibility of NTP engines also provides more options for abort scenarios, as the nuclear engines make it easier to alter the ship’s trajectory for a quick return trip if necessary. This combination of factors positions NTP as a potentially ideal method of transportation for future Mars missions.
Kirk Shireman, Vice President of Lunar Exploration Campaigns for Lockheed Martin, emphasized the importance of reducing transit time for human missions to Mars in order to limit the crew’s exposure to radiation. He stated, “These more powerful and efficient nuclear thermal propulsion systems can provide faster transit times between destinations.” By utilizing NTP technology, NASA and DARPA hope to improve the efficiency and safety of crewed missions to Mars.
The NTP system operates by utilizing a nuclear reactor to rapidly heat hydrogen propellant to extremely high temperatures. The heated gas is then channeled through the engine’s nozzle, generating the thrust required for the spacecraft’s propulsion. BWX Technologies, a company specializing in nuclear technologies, will provide the reactor and fuel for the DRACO project. BWX Technologies stated that the nuclear thermal propulsion system is designed to be extremely safe and reliable, utilizing High Assay Low Enriched Uranium (HALEU) fuel to quickly heat a super-cold gas, such as liquid hydrogen. The resulting expansion of the gas creates thrust, enabling the spacecraft to move more efficiently compared to traditional chemical combustion engines.
To address concerns about potential radioactive leaks, NASA and DARPA have implemented safety measures. The reactor will only be powered up once the spacecraft has reached a “nuclear safe orbit.” This orbit is carefully chosen so that any potential accidents or malfunctions occur outside the zone that could affect Earth. The agencies are targeting a nuclear spacecraft demonstration by 2027, with the spacecraft being launched from a conventional rocket and then moved to an appropriate location above low Earth orbit.
The utilization of nuclear reactors extends beyond propulsion systems. In future missions, nuclear reactors are expected to play a crucial role in powering Martian habitats. NASA has been testing small and portable versions of nuclear reactors since as early as 2018, paving the way for sustainable energy solutions on Mars.
In addition to facilitating crewed missions to Mars, NTP technology could also revolutionize much shorter flights, such as transporting materials to the Moon. Shireman highlights the potential of a safe and reusable nuclear tug spacecraft, stating, “With more speed, agility, and maneuverability, nuclear thermal propulsion also has many national security applications for cislunar space.” NTP presents an opportunity to enhance cislunar operations by providing increased speed and flexibility, opening up possibilities for a range of applications beyond Mars missions.
Overall, the collaboration between NASA, DARPA, and Lockheed Martin represents a significant step forward in advancing nuclear thermal propulsion technology. If successful, the DRACO initiative will not only demonstrate the capabilities of NTP but also pave the way for more efficient and ambitious space missions, including crewed missions to Mars and enhanced cislunar operations.
