Without a manned mission to Mars, the need for a nuclear thermal rocket was unclear.

Typical all-rocket systems are around 450 at best, and even "typical" nuclear thermal rockets only about 900 seconds.

Unmanned missiles have been designed to use nuclear thermal rockets, but such designs were considered too dangerous for crews to fly.

Nuclear thermal rockets can provide great performance advantages compared to chemical propulsion systems.

Uranium carbide fuel was used in late designs of nuclear thermal rockets.

Project Rover was an American project to develop a nuclear thermal rocket.

These methods resemble those proposed for nuclear thermal rockets.

A solar thermal rocket only has to carry the means of capturing solar energy, such as concentrators and mirrors.

Project Timberwind aimed to develop nuclear thermal rockets.

Five astronauts pilot the nuclear thermal rocket powered Pegasus spacecraft on a tour of the solar system.