Project Timberwind aimed to develop nuclear thermal rockets. Initial funding by the Strategic Defense Initiative from 1987 through 1991 totaled $139 million (then-year).[1] The proposed rocket was later expanded into a larger design after the project was transferred to the Air Force Space Nuclear Thermal Propulsion (SNTP) program.
The program underwent an audit in 1992 due to security concerns raised by Steven Aftergood.[1] This highly classified program provided the motivation for starting the FAS Government Secrecy project. Convicted spy Stewart Nozette was found to be on the master access list for the TIMBER WIND project.[2]
Advances in high-temperature metals, computer modelling and nuclear engineering in general resulted in dramatically improved performance. Whereas the NERVA engine was projected to weigh about 6803 kg, the final SNTP offered just over 1/3 the thrust from an engine of only 1650 kg, while further improving the specific impulse from 930 to 1000 seconds.[citation needed]