Murphy’s Law

Use of humans in space operations

While the experienced application of sound engineering principles and practices is a good preventative means of countering Murphy’s Law, the law itself says that this is insufficient. When Murphy’s gremlins do strike, human creativity, problem solving skills, and physical dexterity are the means by which failure or disaster may be avoided.

Hubble Space Telescope upgrade mission. (Public domain)
Hubble Space Telescope upgrade mission. (Public domain)

The four repair and upgrade missions to the Hubble Space Telescope are a very good example. Unlike most satellites, the Hubble Space Telescope was designed for in-space repair and upgrade. It was also placed in an orbit that was accessible to the Space Shuttle. The design engineers wisely identified and used sound terrestrial engineering principles and practices to design the satellite for servicing to repair parts that were expected to fail with usage and to upgrade and replace instruments. Yet, despite this sound planning, Murphy’s gremlins caused parts to fail that were not designed for servicing. (Recall that the primary mirror was not manufactured correctly and that this problem was not discovered because routine end-to-end ground testing of the optical system was not done to reduce program costs—itself a form of Murphy’s Law in action.) Despite these problems, repairs and repair methods were successfully developed that enabled corrective actions to be implemented leading to the successful accomplishment of the telescope’s historic space science. Three additional human servicing missions replaced other failed components and upgraded the scientific instruments to significantly extend the productive operations of the telescope. Compare this to other space science platforms that are abandoned following, what on the Earth, would be readily repairable failures.