Nuclear Thermal Propulsion is Key Enabling Technology for DARPA Effort

Nasa and Pentagon developing nuclear-powered rocket for Mars voyage

Nuclear thermal rocket - Wikipedia

NASA and DARPA Award Contract for a Nuclear Engine to Lockheed Martin - Universe Today

Propulsion – Cosmic Log

5 Mission Applications, Space Nuclear Propulsion for Human Mars Exploration

4.0 In-Space Propulsion - NASA

What are nuclear thermal rockets? Will we ever see them in use? - Quora

The DRACO Project And The Era Of Star Wars-Style Space Fighters – The Organization for World Peace

DARPA's nuclear space propulsion project advances to next phase

Nuclear Thermal Propulsion is Key Enabling Technology for DARPA Effort

Why do we not use nuclear engines for space travel? Will it be more feasible when we perfect the fusion reactor? - Quora