Project TIMBER WIND

Project Timber Wind (1987-1991) and its successor Space Nuclear Thermal Propulsion (SNTP) program (1991-1994) were classified Department of Defense efforts to field an ultra-lightweight particle-bed nuclear-thermal rocket for missile-defense payloads.¹

SDIO spent roughly $139 million before transferring the work to the Air Force, which added about $60 million — total outlays approached $200 million when headquarters halted SNTP in January 1994.¹

Four phases — concept definition, reactor and fuel development, ground-test planning, and cancellation — are documented in audits, congressional testimony, and the 1995 Phillips Laboratory final report.² Earlier congressional and Department of Energy reviews traced the concept's heritage and risk posture.³⁴

  Timeline of Major Events

  Technical Architecture

    Particle-Bed Reactor Core

Fine uranium-carbide particles sintered into porous spheres, coated for hydrogen compatibility, and packed in a zirconium-niobium matrix yielded outlet temperatures near 2700 K.⁷² The target engine produced 25 000 lbf thrust at a specific impulse close to 1000 s while keeping dry mass near 1.65 tonnes—about one-third of a comparable NERVA stage.²

    Support Systems

Turbopump, attitude-control, and nozzle hardware were contracted to Hercules Aerospace, AiResearch, and Grumman; each used carbon-carbon composites to endure hot hydrogen flow.²¹² Propellant-cooled tungsten and lithium-hydride shielding designed at Sandia protected cryogenic tanks and met human-rating thresholds.

    Planned Test Series

1. Fuel-element irradiation loops at Brookhaven and the Idaho National Engineering Laboratory.
2. Hot-hydrogen flow tests of full-scale fuel elements at Arnold Engineering Development Center.
3. Prototype engine firings (1 000 s) inside a vacuum duct at the Nevada Test Site's Saddle Mountain complex.⁷¹³

  Program Organization and Key Personnel

  Oversight, Classification, and Security Disputes

TIMBER WIND functioned as an unacknowledged special-access program; the Inspector-General concluded the status lacked merit after the Air Force released reactor data.⁶ GAO warned that undefined mission requirements and the $400 million ground-test infrastructure estimate posed unacceptable cost risk.¹⁷ External pressure from Aftergood's FOIA campaign and the Nozette espionage case maintained scrutiny and eroded institutional support.¹¹¹⁴

  Cancellation Drivers and Legacy

Post-Cold-War budget cuts removed the missile-defense requirement for a particle-bed upper stage, and NASA judged that existing NERVA-class hardware could serve Mars missions more cheaply.¹¹⁵ The 1993 facility study and environmental review showed that no U.S. site could test a full reactor without major new construction, pushing life-cycle cost beyond $1 billion.⁷⁸ Although the prototype never fired, materials data, fuel-coating techniques, and carbon-carbon structures informed later NASA Mars-vehicle analyses and current DARPA/NASA DRACO plans.²¹⁵ The IG audit and Aftergood's activism are now cited in classification-policy courses as examples of SAP justification pitfalls.⁶¹¹¹⁶

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  References

1. GAO, Space Nuclear Propulsion: History, Cost, and Status of Programs T-NSIAD-93-2. https://www.gao.gov/assets/t-nsiad-93-2.pdf ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸

2. Phillips Laboratory, Space Nuclear Thermal Propulsion Program Final Report PL-TR-95-1064. https://www.osti.gov/biblio/273151 ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸

3. Congressional Research Service, RL 31347 Nuclear Propulsion (1991). https://crsreports.congress.gov/product/pdf/RL/31347 ↩

4. Department of Energy, Space Nuclear Propulsion Program History (1995). https://www.energy.gov/sites/default/files/2021-02/Space_Nuclear_Propulsion_History.pdf ↩

5. Magnetic Glide Technologies, James R. Powell biography. https://www.magneticglide.com/about-us.html ↩ ↩²

6. DoD Inspector-General Audit Report 93-033, TIMBER WIND Special Access Program. https://sgp.fas.org/othergov/dod/tw.pdf ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

7. NASA TM-105708, Space Nuclear Thermal Propulsion Test Facilities Sub-panel Final Report. https://ntrs.nasa.gov/api/citations/19930015916/downloads/19930015916.pdf ↩ ↩² ↩³ ↩⁴ ↩⁵

8. USAF, Final Environmental Impact Statement—Space Nuclear Thermal Propulsion Program. https://ntrs.nasa.gov/api/citations/20140008803/downloads/20140008803.pdf ↩ ↩²

9. NRC docket material referencing the SNTP EIS. https://www.nrc.gov/docs/ML0222/ML022270728.pdf ↩

10. Archive.org copy of PL-TR-95-1064. https://archive.org/details/a305996 ↩

11. Federation of American Scientists, Nozette and Nuclear Rocketry. https://fas.org/publication/nozette/ ↩ ↩² ↩³ ↩⁴ ↩⁵

12. Air Force Research Laboratory hot-hydrogen test fact sheet. https://www.afrl.af.mil/About/Fact-Sheets/Fact-Sheet-Display/Article/2282103/ ↩

13. INL Digital Library reference citing the SNTP EIS. https://inldigitallibrary.inl.gov/sites/sti/sti/4886666.pdf ↩

14. YNet News, US Scientist Indicted for Espionage, 2009. https://www.ynetnews.com/articles/0,7340,L-3794208,00.html ↩ ↩²

15. NASA Space Nuclear Propulsion Office Report, 1994. https://www.nasa.gov/sites/default/files/atoms/files/nasa_space_nuclear_propulsion_1994.pdf ↩ ↩²

16. New Space Economy, Rise and Fall of Project Timber Wind (2024). https://newspaceeconomy.ca/2024/02/16/the-rise-and-fall-of-project-timberwind-americas-secret-nuclear-rocket-program/ ↩