Air Force Launch Failure Risk Model, Mode-5 Deviations

Brief

Prepared by Research Triangle Institute under Air Force contract FO4703-91-C-0112 for the 30th and 45th Space Wing Safety Offices, this final report addresses the subset of launch failures in which a rocket executes a sustained turn away from the intended flight line — designated Mode-5 responses — and develops optimum shaping constants for the associated impact density function used in the DAMP risk-analysis program. Shaping constants are selected by simulating control and guidance malfunctions for Atlas IIAS, Delta-GEM, Titan IV, and LLV1 configurations, then matching simulated impact distributions to the theoretical function by trial and error. A comprehensive appendix catalogs the launch and failure history of Atlas (532 flights), Delta (232), Titan (337), and Thor (85) through August 1996. This document contains no UAP content and is entirely a technical aerospace-safety study.

Metadata

Agency

Department of War

Release

5/8/26

Incident

9/10/96

Type

PDF • .pdf

Length

181 pages

Classification

UNCLASSIFIED

Programs

DAMP

Tags

Mode-5 failure, launch vehicle, risk modeling, Atlas, Delta, Titan, Thor, DAMP program, Eastern Range, Western Range, Patrick AFB, Vandenberg AFB, 1996, non-UAP filing

Key points

• Mode-5 failures — the document's central subject — are defined as sustained vehicle turns away from the flight line caused by control failures (e.g., a rocket engine locked near null) or erroneous guidance-platform orientation, distinct from the more common catastrophic breakup modes.p.10
• The DAMP impact density function for Mode-5 events uses two shaping constants: constant A governs the angular falloff from the flight line, and constant B governs the range falloff; both are calibrated by simulation rather than analytical derivation.p.4
• Shaping constants are selected by trial and error — malfunctions are simulated, and the constants chosen so that simulated and theoretical impact distributions agree.p.4
• The launch and failure history appendix covers 532 Atlas, 232 Delta, 337 Titan, and 85 Eastern-Range Thor flights, totaling 1,186 launches (Table 11).p.8
• DAMP explicitly excludes fire, toxic-material, and radiation hazards from its risk calculations, addressing only debris impact, overpressure, and secondary debris.p.10
• The six DAMP failure-response modes are tiered by standoff distance: Modes 1-3 produce impacts within roughly a mile or two of the launch point; Mode 4 scatters debris near the flight line; Mode 5 can place debris many miles off the flight line.p.10
• Distribution of the report is restricted to US Government agencies and their contractors; all other requests are to be routed to 30 SW/SE at Vandenberg AFB or 45 SW/SE at Patrick AFB.p.1
• Shaping-constant analysis is completed for Atlas IIAS, Delta-GEM, Titan IV, and LLV1; a summary table of A-values at B = 1,000 covers additional launch vehicles (Table 26).p.9

Verbatim

• In computing launch-area risks, DAMP makes no attempt to model vehicle failures per se. A list of possible failures for any vehicle would be extensive, and variations in failures from vehicle to vehicle would complicate the modeling process. Instead, DAMP models failure responses.

  p.10

• Such failures should not be ignored, since they may produce nearly all or a significant part of the risks to population centers that are more than a mile or so uprange or many miles away from the flight line.

  p.10

• Missile and space-vehicle performance histories contain many examples of failures that cause, or have the potential to cause, significant vehicle deviations from the intended flight line.

  p.3

• Certain Mode-5 malfunctions are simulated, and the two shaping constants then chosen by trial and error so that impacts from the simulated malfunctions and the theoretical density function are in close agreement.

  p.4

• The empirical data are then filtered to estimate (1) failure probabilities for Atlas, Delta, and Titan, and (2) percentages of future failures that will result in Mode-5 (and other Mode) responses.

  p.4

• Although fire, toxic materials, and radiation may also subject personnel to significant danger, these hazards are not addressed in program DAMP.

  p.10

• Small hazards exist even outside these lines if the flight termination system fails or other unlikely events occur.

  p.10

Most interesting

• This document was catalogued as DOW-UAP-D48 under the May 2026 UAP disclosure but contains no UAP content whatsoever — it is a technical aerospace launch-safety study.
• The DAMP program (facility DAMage and Personnel injury) was RTI's prototype risk-analysis tool for estimating hit probabilities and casualty expectations from launch-vehicle failures in the launch area.
• Mode-5 is described as a theoretical construct deliberately engineered to capture real but rare flight-test observations of vehicles executing long, sustained deviation maneuvers — the kind that can threaten population centers miles from the flight corridor.
• The two shaping constants for Mode-5 (A and B) have no closed-form derivation; they are found empirically by running malfunction-turn simulations and adjusting until the theoretical density function matches the simulated impact scatter.
• The failure history appendix spans from the beginning of each missile program (Atlas, Delta, Titan, Thor) through August 1996 — making it one of the most comprehensive unclassified U.S. orbital-launch failure databases available at that time.
• Funding and tasking came from two separate Space Wing Safety Offices simultaneously — 30 SW/SE at Vandenberg (Western Range) and 45 SW/SE at Patrick AFB (Eastern Range) — reflecting the need to harmonize risk models across both U.S. launch sites.