posted 06-22-2005 08:02 PM               

The switch on the left is a Klixon as used in the Apollo Command Module and the ones in the center and right hand side are McGraw-Edison as used in the Space Shuttle orbiter.

The one on the right has the "pull to unlock" knob for more critical applications. The Klixon is the "Block II" design modification after the tragic Apollo 1 fire in 1967.

posted 06-23-2005 12:08 PM               

The "suspect" switch in the Apollo 1 disaster was made by Micro Switch. That switch and others were replaced by better-designed switches by Klixon, such as the first one shown in the pictures. For the Shuttle program, a new series of toggle switches was produced by McGraw-Edison and later by Armtec and, most recently, Applied Research. These are high precision, hermetically sealed toggle switches with welded titanium bodies and titanium mounting hardware and cost more per ounce of weight than gold or platinum.