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 carry out the first in-orbit test of a nuclear thermal rocket by 2027. Fueled by low-enriched uranium, 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 such as 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 President's Budget Request confirmed DRACO's cancellation, with no funding allocated to nuclear thermal or electric propulsion programs, deemed by the Trump administration as expensive, and DARPA had completed its program termination procedures, transferring the knowledge to NASA. In late June 2025, DARPA announced that the termination was based on an assessment that the costs no longer matched the benefits and that decreasing launch costs and new analysis led to its cancellation. Although the Senate Appropriations Committee has indicated a preference for maintaining current funding levels for NSF and NASA, resisting the Trump administration's proposed drastic cuts, which support suggests a potential safeguard for ongoing research and missions including other projects that might involve NTP and NEP, the cancellation of DRACO is final due to DARPA's withdrawal from it.