Johnson Space Center

Johnson Space Center, a product of the "space age,” is NASA’s core cen­ter for human space flight, development of launch vehicles and systems, astronaut training, and human space flight operations. As a Center with significant hardware development and operational responsibilities, Johnson’s activities in analysis methods have been "usually directed to specific problems relating to developing hardware that the Center is responsible for.”[901]

Except for moderate downsizing in the 1980s and minor organiza­tional changes such as separating Structures and Dynamics into two branches, the structures-related organization has been relatively sta­ble over several decades. The Structural Engineering Division (ES) has approximately 120 employees divided into 5 branches: Structures, Dynamics, Thermal, Material, and Mechanisms. The Structures Branch (ES2) has responsibility for structural design, analysis (including com­puter methods), and testing.[902] Johnson has some very significant test facilities, including a tower that can hold a full Apollo or similar-sized

vehicle and subject it to vibration testing.[903] Current directions at Johnson include sustaining activity for the Space Shuttle and the International Space Station (ISS), and new work related to the Orion spacecraft.[904]

With the emphasis on hardware and systems development, rather than on methods development, Johnson has favored the use of computer programs already available when they can meet the need. According to Modlin:

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Prior to NASTRAN we used the SAMIS program that was developed by JPL for stress and dynamics, our inputs regard­ing NASTRAN were directed to the NASTRAN office at NASA Langley after the program was delivered, but we did not do any development on our own. We and our contractor wanted to use NASTRAN on the Shuttle Orbiter, but required substructuring.

This wasn’t delivered in time [as a NASTRAN capability] so the contractor continued with ASKA. . . . Some programs developed in house relate to: Lunar landing, Apollo Crew Module water landing and flight loads. One more general program that has wide use is NASGRO (formerly FLAGRO), which was devel­oped by Royce Forman. It is a fracture mechanics routine.[905]

Although this paper has not attempted to cover fracture mechanics, it is worth noting that NASGRO, originally developed for space applica­tions, has been enhanced with "many features specifically implemented to suit the needs of the aircraft industry,” because of increasing focus in the Federal Aviation Administration (FAA), NASA, and DOD on safety of aging aircraft.[906]

Other programs developed at Johnson or under Johnson sponsorship include TRASYS (Thermal Radiation Analysis System, 1973), FAMSOR (Frequencies and Modes of Shells Of Revolution, 1974), SNASOR (Static

Nonlinear Analysis of Shells of Revolution, 1974), BUCKY (Plate buck­ling, 1992), and COMPAPP (Composite plate buckling, 1994).[907]