[TenTec] Lubricants

[AL_LORONA@HP-USA-om33.om.hp.com]

     Hi everybody,
     
     Steve has probably put his finger on the essence of the PTO 
     controversy with his observation of the quality of the lubricant.
     
     Back in the early 80s I worked at JPL with a crack engineer whose job 
     it was to find out why the camera scan platform of the Voyager 
     spacecraft got stuck on the Saturn flyby. The scan platform slews the 
     camera and other instruments up, down, left, and right. (If you 
     remember, much valuable data and many pictures were lost because of 
     the failure.) The Lab was very interested in salvaging any movement of 
     the scan platform for the expected encounter with Uranus so that the 
     maximum science (photos) could be gained.
     
     We made dozens of replicas of the scan platform's gearbox and then we 
     turned 'em on. Carl was a gearbox expert. We ran some continuously, 
     others intermittently, some rapidly and others slowly, still others at 
     high temp and others at cold temp, and collected statistics on them 
     all while they whirred frantically up in the gyro room. One by one, 
     they jammed up just like the original one.
     
     When Carl finally finished his investigation, he concluded that a bad 
     batch of lubricant that prematurely hardened and clogged the precision 
     teeth of the gears was the cause of the failure, but he also found out 
     the exact parameters of movement range, frequency, and rate that would 
     allow NASA to maximize its very limited remaining gear box life. As a 
     result, the Uranus flyby was a success and Voyager 2's mission was 
     extended to include Neptune in 1989, which was at that time the 
     farthest planet from the sun.
     
     I'm afraid that failures of gearboxes and PTO shafts can happen to the 
     best of us, but thank goodness that, here on Earth, we have the luxury 
     of merely opening up our PTOs and adding a little Teflon lube after 
     cleaning up the shaft. It's so much easier.
     
     R,
     
     Al W6LX
     
     P.S. For fascinating info on the two Voyager spacecraft, check out  
     http://vraptor.jpl.nasa.gov/voyager/voyager.html


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