Project Timberwind


Project Timberwind aimed to develop nuclear thermal rockets. Initial funding by the Strategic Defense Initiative from 1987 through 1991 totaled $139 million. The proposed rocket was later expanded into a larger design after the project was transferred to the Air Force Space Nuclear Thermal Propulsion program and underwent an audit in 1992 due to concerns raised by Steven Aftergood. This special access 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.
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.

Timberwind Specifications

Timberwind 45

In contrast to the TIMBER WIND project, the Space Nuclear Thermal Propulsion program was intended to develop upper-stages for space-lift which would not operate within the Earth's atmosphere. SNTP failed to achieve its objective of flight testing a nuclear thermal upper-stage, and was terminated in January 1994. The program involved coordinating efforts across the Department of Defense, the Department of Energy, and their contractors from operating sites across the U.S. A major accomplishment of the program was to coordinate Environmental Protection Agency approvals for ground testing at two possible sites.
NameLocationResponsibilities
Brookhaven National LaboratoryUpton, NYReactor materials and components testing; thermal-hydraulic, and neutronic analysis; reactor design studies
Babcock & WilcoxLynchburg, VAReactor design testing, fabrication and assembly
Sandia National LabsAlbuquerque, NMNuclear safety, nuclear instrumentation and operation, reactor control system modeling, nuclear testing
Aerojet Propulsion DivisionSacramento, CAFuel element alternate materials development
Hercules Aerospace CorporationMagna, UTDesign and fabrication of engine lower structure and nozzle
Garrett Fluid Systems DivisionTempe, AZ and San Tan, AZDesign and fabrication of attitude control system, propellant flow control system and turbopump assembly
AiResearch Los Angeles Division of Allied SignalTorrance, CATurbine wheel testing
Grumman Space Electronics DivisionBethpage, NYVehicle design and fabrication, systems integration
Raytheon Services NevadaLas Vegas, NVFacility and Coolant Supply System engineering, facility construction management
Reynolds Electrical and Engineering Company, IncLas Vegas, NVFacility construction
Fluor-Daniel, Inc.Irvine, CAEffluent Treatment System engineering
Sandia National LabsSaddle Mountain Test Site or QUEST or LOFT SitesTest site preparation, planning and performance of engine ground tests, nuclear component testing
Washington, DCProgram management
DoE HeadquartersWashington, DCProgram management, nuclear safety assurance
DoE Nevada Test SiteLas Vegas, NVGround testing
DoE Idaho National Engineering LabIdaho Falls, IDGround testing
U.S. Air Force Phillips LabAlbuquerque, NMProgram management
U.S. Army Corps of EngineersHuntsville, ALETS engineering management
Los Alamos National LaboratoryLos Alamos, NMFuels and materials testing
Marshall Space Flight Center Huntsville, ALMaterial and component simulation/testing
Western Test Range/Western Space & Missile Center Vandenberg AFB, CAProgram review
Arnold Engineering Development CenterManchester, TNHydrogen flow testing
UNC Manufacturing CompanyUncasville, CTMaterials manufacturing
Grumman Corporation - Calverton FacilityLong Island, NYHydrogen testing

The planned ground test facilities were estimated to cost $400M of additional funding to complete in 1992. Fewer than 50 sub-scale tests were planned over three to four years, followed by facility expansions to accommodate five to 25 1000 second full-scale tests of a 2000MW engine.
The program had technical achievements as well, such as developing high-strength fibers, and carbide coatings for Carbon-Carbon composites. The hot-section design evolved to use all Carbon-Carbon to maximize turbine inlet temperature and minimize weight. Carbon-Carbon has much lower nuclear heating than other candidate materials, so thermal stresses were minimized as well. Prototype turbine components employing a 2-D polar reinforcement weave were fabricated for use in the corrosive, high-temperature hydrogen environment found in the proposed particle bed reactor -powered engine. The particle bed reactor concept required significant radiation shielding, not only for the payload, electronics and structure of the vehicle, but also to prevent unacceptable boil-off of the cryogenic propellant. A propellant-cooled, composite shield of Tungsten, which attenuates gamma rays and absorbs thermal neutrons, and Lithium Hydride, which has a large scattering cross section for fast and thermal neutrons was found to perform well with low mass compared to older Boron Aluminum Titanium Hydride shields.
Sandia National Labs was responsible for qualification of the coated particle fuel for use in the SNTP nuclear thermal propulsion concept.
ProCon
Bleed CycleDevelopment of high temp turbine and feed lines required
Partial Flow Expander Cycle