Titan IV is a multistage space-launch vehicle designed to carry heavy payloads. Titan IV consists of two United Technologies solid rocket motors (SRM), a two-stage liquid-fueled core vehicle built by Lockheed Martin, and three configurations of upper stages: Lockheed Martin Centaur, Boeing Inertial Upper Stage (IUS), or no upper stage (NUS). Titan IV/NUS is capable of placing 31,100 pounds into polar low earth orbit (LEO). Titan IV/Centaur can place 10,300 pounds in geosynchronous earth orbit (GEO). A solid rocket motor upgrade (SRMU), which will increase LEO payload performance to 38,500 pounds and GEO performance to 11,500 pounds, is under development.
The Air Force operates Titan IV launch complexes at Cape Canaveral Air Station (CCAS), FL, and Vandenberg Air Force Base (VAFB), CA.
Development of Titan IV was authorized by National Security Decision Directive 164 to ensure heavy lift access to space comparable to space shuttle payload capability. Titan IV is a direct descendant of the Titan family of ICBMs and the Titan 34D medium payload launch vehicle. Titan IV development began with a contract award to Martin Marietta (now Lockheed Martin) in February 1985. The first core vehicle was delivered to CCAS in January 1988, and Initial Launch Capability (ILC) was achieved with the first launch in February 1989. The Titan IV program is unique because the Air Force is not responsible for the vehicle until it lifts off the launch pad. Lockheed Martin and the payload manager are jointly responsible for prelaunch activities.
Ten Titan IV launches have been conducted prior to FY95, with nine of the flights successful. Three Titan IV vehicles were successfully launched in FY95.
The SRMU program was initiated in 1987 to improve payload performance and overall system reliability. The program included two planned qualification test (QT) firings and two planned engineering test (ET) firings. After some initial problems, the SRMU test program was completed in FY94. ILC for SRMU is currently planned for July 1996.
Titan IV is meeting user requirements for payload weight and orbital insertion accuracy. However, demonstrated reliability is currently below the ORD threshold.
Titan IV did not meet the formal ORD payload requirements on every launch. In these operational launches, the developer chose vehicle configurations to match the payload needs of the user. This practice led to payload weight capacity being below the ORD threshold on 3 of the 12 launches for which data were available. The shortfalls were small (26, 21, and 161 pounds) and each Titan IV vehicle could have been configured to meet the ORD payload requirement had it been necessary to do so. Thus the failure to meet the formal ORD requirement on these three launches does not constitute an actual deficiency.
Given that launch vehicle configuration is subject to the availability of the various upper stages, a real shortfall could occur in the future. This issue is still open.
The ORD threshold for Titan IV launch-and-inflight reliability (LIR) is 0.96. With 12 successes in 13 flights, observed LIR is at 0.92. With a sample size of 13, the 90% confidence bounds on this point estimate are 0.683 and 0.997. More precise estimates of LIR will be possible when more flights have occurred.
The ORD thresholds for annual launch throughput rates are four Titan IV launches per year at CCAS and two per year at VAFB. AFOTEC has estimated throughput capacity in two different ways: (1) the observed number of launches per year over the history of the program, and (2) a theoretical calculation that discounts delays judged not to be attributable to the Titan IV vehicle. Observed launches per year, as of August 1995, are 1.23 at CCAS (9 launches in 7.29 years) and 0.74 at VAFB (4 launches in 5.42 years). At each complex, there have been brief periods during which the launch rate was at the threshold. The timeline at CCAS has been improving over time, as launch personnel have become more familiar with Titan IV. AFOTEC_s theoretical calculations yield rates of 3.76 at CCAS and 1.85 at VAFB. While the assumptions supporting these estimates might be criticized, they do provide an indication of the potential performance of the system. Given these potential throughput rates and the observed trend toward improvement in the timelines, Titan IV appears to be on track to meet its throughput requirement.
The SRMU program has successfully completed its development phase and is awaiting the first launch requirement. When the launch is at hand and the processing is complete, SRMU should be certified ready for launch. At that time SRMU will come under DOT&E oversight.
The Titan IV TEMP is current.
Titan IV payload weight and orbital delivery accuracy performance has met the user_s requirements in each successful launch. Titan IV ability to meet the ORD payload weight requirements in future launches, given the resources that will be available, remains to be determined. The current point estimate of launch-and-inflight reliability is below the ORD threshold, but the relatively small sample size leaves open the possibility that LIR is compliant with the ORD requirement. Prelaunch processing is making vehicles available when needed despite taking longer than specified in the ORD.
The current Titan IV system is performing in a manner acceptable to its user community. The cost and complexity of the system, together with the fact that it has not yet convincingly demonstrated the required levels of reliability and throughput, indicate that continued DOT&E oversight is required.
No assessment of SRMU is feasible at this time. DOT&E will begin assessing effectiveness and suitability when SRMU is launched.