Demonstration Rocket for Agile Cislunar Operations

The Demonstration Rocket for Agile Cislunar Operations (DRACO) was a planned spaceflight demonstration mission under the joint auspices of DARPA, NASA, Lockheed Martin, and BWX Technologies, aiming to demonstrate nuclear thermal propulsion in orbit by 2027. DRACO was expected to be the first in-orbit test of a nuclear thermal rocket engine using low-enriched uranium, and its reusability and performance were projected to significantly outpace current chemical propulsion systems. Launch operations were to be supported by the U.S. Space Force, with the Vulcan Centaur rocket identified as the planned launch vehicle. In 2023, NASA formally joined the DRACO program, seeking to leverage nuclear propulsion to drastically reduce travel time to deep-space destinations such as Mars. Nuclear thermal propulsion was expected to yield two to three times the efficiency of chemical propulsion, with mission durations to Mars potentially cut in half. DARPA program manager Tabitha Dodson remarked that nuclear propulsion could form the foundation for evolving systems such as fusion-based spacecraft, enabling more ambitious human exploration missions with greater safety margins. According to Lockheed Martin and BWXT, there were considerable efficiency and time gains from the nuclear thermal propulsion. NASA believed the much higher efficiency will be two to three times more than chemical propulsion, and the nuclear thermal rocket is to cut the journey time to Mars in half.

However, by January 2025, the mission's planned 2027 launch was placed on indefinite hold due to technical and regulatory challenges – specifically, the complex safety and testing requirements for ground-based nuclear reactor validation and the unresolved final design of the propulsion system. The program's status was further impacted by the May 2, 2025 release of the FY2026 federal budget, which proposed a $531 million cut to NASA’s Space Technology Mission Directorate. The budget documentation cited reductions in unspecified advanced space propulsion projects. Some analysts interpreted this as effectively ending nuclear propulsion research, noting similarities to NASA’s earlier cancellation of Project Prometheus..

On May 30, 2025, the finalized FY2026 budget confirmed DRACO's cancellation, with no funding allocated to Nuclear Thermal or Electric Propulsion programs, and DARPA has completed its program termination procedures. This cancellation may meet with serious opposition from Congress and industry leaders.