DEPARTMENT OF THE AIR FORCE SMC REGULATION 800-30
Headquarters Space and Missile Systems Center (AFMC)
Los Angeles Air Force Base, California 90009-2960
INDEPENDENT STRUCTURAL LOADS ANALYSES OF INTEGRATED
SPACECRAFT, LAUNCH VEHICLES, AND TRANSPORTER SYSTEMS
This regulation establishes policies and procedures and assigns responsibilities for Space and Missile Systems Center (SMC) space programs to obtain independent structural dynamic loads analyses of integrated spacecraft/launch vehicle systems and of a limited class of integrated space vehicle/transporter systems.
1. Policy All SMC space programs shall perform an independent fully coupled structural dynamic loads analysis of the integrated spacecraft/launch vehicle system, and of certain integrated space vehicle/transporter systems, to verify the accuracy and completeness of the contractor loads analysis. Test programs which form the basis of the loads analysis models and methodology shall be independently certified.
2. Background Dynamic loads occurring during launch and ascent are the principal factors in establishing the structural design requirements of spacecraft and are major contributors to launch vehicle loads. For spacecraft using space launch systems which return from orbit, and for some large space systems which are transported by aircraft, dynamic loads occurring during atmospheric flight and landing may also significantly impact structural design requirements. Determination of dynamic loads requires complete and comprehensive analysis of the integrated system. The results are highly sensitive to dynamic model interaction effects and to assumptions made in the event simulations. Test-verification of critical analysis elements, such as dynamic models, therefore, substantially increases the validity and credibility of the analysis results. In addition, because of the complexity of the systems, deficiencies or errors in the testing, model-to-test correlation, and response analyses often occur. They are difficult to detect and can significantly affect the structural loads determinations. Such problems could compromise structural integrity assessments which use the loads data, thereby jeopardizing mission success. The independent analyses and evaluations are highly effective in uncovering and eliminating such problems. For transportation loads, such comprehensive efforts are only necessary when the analyses are sensitive to interactions between the dynamic models of the component structures, and when the resulting loads may exceed flight loads.
3. Responsibilities and Procedures
a. The SMC spacecraft program office, in coordination with the launch vehicle program office, is responsible for the performance of a fully coupled dynamic loads analysis of the integrated spacecraft and launch vehicle system. This primary analysis set will evaluate all dynamic load conditions which may be critical, from the initiation of countdown through powered flight and payload separation or landing, as the case may be. The analysis is to be updated as appropriate and culminate in a verification load cycle using test-verified elements in the analysis. Transportation loads analyses are also to be performed, as appropriate, with the assistance of the transporter program office.
b. The SMC spacecraft program office, in coordination with the launch vehicle program office and concurrent with the verification load cycle, shall obtain an independent loads analysis for the integrated spacecraft and launch vehicle system. This analysis is to evaluate all critical dynamic load conditions. Similar independent analyses shall also be obtained for any transportation events which are sensitive to dynamic model interaction effects and which produce loads that may exceed flight loads. Any significant differences in interim or final results between the primary and independent analyses shall be resolved expeditiously.
c. The SMC launch vehicle program office shall support the spacecraft program office in obtaining appropriate analysis services and in facilitating the data interchanges necessary to accomplish the primary and independent loads analyses.
d. Any separate SMC transporter system program office shall support the spacecraft program office in obtaining appropriate analysis services and in facilitating the data interchanges necessary to accomplish the primary and any independent loads analyses, as required.
e. The responsible SMC program offices shall obtain independent certification of the tests or data which form the basis of the test-verified models and model parameters to be used in the verification load cycle.
f. For launch vehicles (such as NASA's Space Transportation System), spacecraft, or transporter systems developed and verified by other governmental agencies, the responsible SMC program office shall coordinate with the agency to evaluate their independent assessment effort, resolve problem areas, and-- if necessary-- define appropriate actions to maintain a risk level for the SMC segment consistent with SMC program objectives. Unnecessary duplication of effort is to be avoided.
g. The document SAMSO Pamphlet 800-5, "Independent Structural Loads Analyses of Integrated Payload/Launch Vehicle Systems", has been developed to aid program offices in the implementation of this policy. It defines the pertinent nomenclature, describes the loads analysis procedures, defines a typical loads analysis plan for acquiring loads information in a manner compatible with program schedules and milestones, provides criteria for independent loads analyses, describes management procedures for incorporating the necessary analyses and tests into the SMC program, identifies data interchange requirements, and discusses program-peculiar considerations and options available to the program director in prescribing the scope of the independent analysis program.
h. Atmospheric data (wind and density) used in the analyses are to be coordinated through SMC's Chief Engineer's Office (SMC/SDEW-Weather Office).
i. Instructions for applying and executing this regulation are provided by SMC Regulation 540-15 (Systems Engineering Policy). Any program director who does not apply and excecute this regulation as required by SMCR 540-15 shall immediately request a waiver from the Commander.
Edward P. Barry, Jr.
Lieutenant General, USAF