Survey of Flexibility in Space Exploration Systems

Paper number

IAC-08.D3.1.5

Author

Mr. Jarret Lafleur, Georgia Institute of Technology, United States

Coauthor

Dr. Joseph Saleh, Massachussets Institute of Technology (MIT), United States

Year

2008

Abstract

In January 2008, Dr. Michael Griffin spoke to the Space Transportation Association on the rationale behind NASA's choice of exploration architectures.  In his speech, he cautioned against designing aerospace systems for very specific roles.  He added, "Even though from an engineering perspective it would be highly desirable to have transportation systems separately optimized for LEO and deep space, NASA's budget will not support it.  We get one system; it must be capable of serving in multiple roles ... We are designing today the systems that our grandchildren will use as building blocks, not just for lunar return, but for missions to Mars, to the near-Earth asteroids, to service great observatories at Sun-Earth L1, and for other purposes we have not yet even considered. We need a system with inherent capability for growth."

These remarks emphasize flexibility, an increasingly common objective for new space systems.  Flexibility can be defined as the capability to easily modify a system in response to a changing environment or new requirements. The body of research on this topic has been growing, but substantial work remains in developing metrics for characterizing system flexibility and trading it against other metrics. In this paper, we sample from space exploration history to glean heuristic insight into fundamental characteristics of flexibility in space exploration systems and their potential application to future systems.

This survey begins with the Hubble Space Telescope, a classic example of a serviceable space system.  Data is presented on servicing activities and resulting performance gains throughout Hubble's lifetime.  The mission flexibility of the Space Shuttle is also presented, as is Apollo and the characteristics that enabled it to fulfill ten distinct mission types plus the Apollo-Soyuz and Skylab missions.  Furthermore, proposals of the Apollo Applications Program are used as evidence of additional flexibility potential in the Apollo design.  Mir and the International Space Station are, additionally, used as examples of modular flexibility. Finally, robotic missions such as the Venera series, Mars Exploration Rovers, and Galileo are shown to exhibit flexibility during their operational lifetimes.

One important conclusion from this survey is that few systems are entirely inflexible.  Distinctions must be made between degrees of flexibility in a system as well as between different types of flexibility. This paper discusses distinct categories of flexibility in exploration systems and contributes a further step in developing a theory of flexibility and comprehensive methods for designing this property into new space systems.

Abstract document

IAC-08.D3.1.5.pdf

Manuscript document

IAC-08.D3.1.5.pdf (🔒 authorized access only).

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