Hubble Focusing Issues [ August 4th, 2008 ] Posted in » Root Cause Analysis - Incident Investigation

Hubble TelescopeThe Hubble Space Telescope was launched on April 24, 1990.  Once in orbit, it was quickly discovered that the images from Hubble were blurred.  An investigation into the issue revealed that Hubble’s primary mirror was not built to specification and couldn’t properly focus the light.  Specifically, the mirror was flattened too much away from the center and caused the light reflected from the edge of the mirror to focus on a slightly different location than the light reflected from the center.   The primary mirror in Hubble was only off specification by 2.3 micrometers, but the result to the $1.5 billion dollar project was disastrous. 

Solving Hubble’s focus issues was no small feat.  How do you repair a mirror that can’t be replaced on orbit when it is cost prohibitive to bring it back to earth for repair?  The answer was to modify the lens (which met specifications) to work with the off specification mirror.  COSTAR (Corrective Optics Space Telescope Axial Replacement) was added to Hubble during the first servicing mission in December 1993.  COSTAR is essentially eyeglasses for Hubble, additional lens built with the same error as the mirror, but in the opposite direction so that the effects of the off specification mirror shape are canceled out.  With the addition of COSTAR, Hubble met original design goals.

The primary mirror was constructed with a flaw because the tool, called a null corrector, used to create the template to guide the shaping of the mirror was itself flawed.  Null correctors use precisely located mirrors and lens to determine the shape of a mirror.  In order to assemble null correctors, reflected light is used to measure the distance between the mirror and the lens inside the tool.  When the null corrector used to shape the Hubble’s primary mirror was assembled a measurement error was made.  A small amount of reflective coating had fallen off an internal piece of the instrument and the laser used to perform the measurement reflected off the wrong location, resulting in a lens being 1.3 mm to far from the mirror.  Null correctors are extremely precise and do not change once assembled so the Hubble team used a single instrument to guide the mirror shape.  A single flawed tool and inadequate quality controls resulted in a flawed mirror.

Root Cause Analysis :: Hubble Focus Issue A visual representation of root cause analysis has been created as a Cause Map that can be downloaded.

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Pet Food Contamination - UPDATE

On May 22, 2008, Menu Foods and other pet food manufacturers agreed to a settlement on the class action lawsuit resulting from last year’s pet food contamination.  As part of the settlement, they will set up a $24 million fund to reimburse owners for expenses relating to pet deaths or injuries, screenings, and as compensation for food purchases.  This is in addition to $8 million that has already been paid to owners.  Also, they are required to screen for melamine, which owners say they are already doing.

The pet food manufacturers are bearing the brunt of the expense relating to the contamination issue.  But a root cause analysis shows that a significant portion of the blame lies in the regulatory process and dishonest raw material suppliers.  After all, the pet food manufacturers made pet food using raw materials that had been certified as meeting their requirements (which called for no foreign material contamination) and had not been flagged by the FDA. 

It has become increasingly clear that the FDA is not able to properly due its job in the increasingly global nature of U.S. foods and drugs.  The contaminated heparin found earlier this year shows that changes are too slow being made.  And, there is new evidence that private laboratory testing companies in the United States do the bidding of foreign importers who hire them, not the FDA.  These labs have stated that testing results for food entering the United States, no matter what kind of contamination they show, belong to the company.  This means that the results may only be released to the FDA once the company desires - or once a positive result has been obtained - no matter how many rounds of testing that requires.  Some labs have also claimed that importers “lab shop” - sending samples to lab after lab until they get the result they want.  Labs are not required to submit samples to the FDA.  So, the FDA may be in the dark about companies that repeatedly have contamination in their food products.

Dr. David Acheson, the FDA’s assistant commissioner for food protection supports congressional proposals that private labs be accredited by the FDA.  Hopefully action will be taken soon, before more tragedies occur.

July 7th, 2008 | Leave a Comment

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