This is such a lovely story of an engineer who knew his stuff and saved the day!

The W. M. Keck Observatory is a two-telescope astronomical observatory near the summit of Mauna Kea in the U.S. state of Hawaii. The total funding to the Keck telescopes is in the billions of dollars, and it’s responsible for some wonderful astronomical research.

But recently, a problem brought operation of the Keck 1 telescope to a (literal) grinding halt: it couldn’t move.

One diligent engineer found the cause of the failure: a broken LED that cost only 10 cents. After flipping through the telescopes schematics, the engineer–by a thorough understanding of the telescope’s systems–was able to diagnose and repair a ridiculously expensive piece of astronomical equipment. The engineer notes that the dead LED was probably about 30 years old and likely cost about 10 cents. Fortunately, Keck 1 is back up and running!

Little things can make a big difference. Sometimes the design placement of a single LED is the difference between success and failure. And to all the engineers and scientists: it really pays to know how your tools work, inside and out!