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Re: MARS Climate Observer -- Failure Mode



On a much less critical note:

A few balloon launches back we noticed that the balloon GPS data
said the payload was at 20,000 feet an hour after launch.  It was
SUPPOSED to be at 60K+ feet.

You guessed it.  The GPS was putting out altitude in meters,
and the ground software wasn't doing the conversion.  Fortunately
the simple analog temperature sensor told the true story, although
less accurate (temp to altitude conversion). We finally figured
out that things were working.  We just weren't translating.

We got off much cheaper than NASA...

Andy W5ACM


On Fri, 1 Oct 1999, Dr Thomas A Clark (W3IWI) wrote:

> This would be funny if it wasn't so sad! NASA today released a
> report on the reason that the the Mars Climate Observer had its
> catastrophic failure last week. The Locheed-Martin (LockMart -- your
> one stop aerospace contractor) team in Colorado transmitted some
> crucial data to the JPL controllers. Unfortuanately, LockMart
> used English (feet-inches) and JPL expected metric units. The
> result was that the spacecraft was destroyed as it slammed into the 
> Martian atmosphere. The following press release is on the NASA web 
> site at URL
> 
>       ftp://ftp.hq.nasa.gov/pub/pao/pressrel/1999/99-113.txt
> 
> Tom
> 
>   ---------------------------------------------------------------
> 
> > MARS CLIMATE ORBITER TEAM FINDS LIKELY CAUSE OF LOSS
> > 
> >      A failure to recognize and correct an error in a transfer of 
> > information between the Mars Climate Orbiter spacecraft team in 
> > Colorado and the mission navigation team in California led to the 
> > loss of the spacecraft last week, preliminary findings by NASA's 
> > Jet Propulsion Laboratory internal peer review indicate.
> > 
> >      "People sometimes make errors," said Dr. Edward Weiler, 
> > NASA's Associate Administrator for Space Science. "The problem 
> > here was not the error, it was the failure of NASA's systems 
> > engineering, and the checks and balances in our processes to 
> > detect the error.  That's why we lost the spacecraft."
> > 
> >      The peer review preliminary findings indicate that one team 
> > used English units (e.g., inches, feet and pounds) while the other 
> > used metric units for a key spacecraft operation.  This 
> > information was critical to the maneuvers required to place the 
> > spacecraft in the proper Mars orbit.  
> > 
> >       "Our inability to recognize and correct  this simple error 
> > has had major implications," said Dr. Edward Stone, director of 
> > the Jet Propulsion Laboratory.  "We have underway a thorough 
> > investigation to understand this issue."
> > 
> >     Two separate review committees have already been formed to 
> > investigate the loss of Mars Climate Orbiter: an internal JPL peer 
> > group and a special review board of JPL and outside experts. An 
> > independent NASA failure review board will be formed shortly.
> > 
> >      "Our clear short-term goal is to maximize the likelihood of a 
> > successful landing of the Mars Polar Lander on December 3," said 
> > Weiler. "The lessons from these reviews will be applied across the 
> > board in the future."
> > 
> >      Mars Climate Orbiter was one of a series of missions in a 
> > long-term program of Mars exploration managed by the Jet 
> > Propulsion Laboratory for NASA's Office of Space Science, 
> > Washington, DC.  JPL's industrial partner is Lockheed Martin 
> > Astronautics, Denver, CO.  JPL is a division of the California 
> > Institute of Technology, Pasadena, CA.
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