[Elecraft] Buggy software OT

[Lynn W. Taylor, WB6UUT]

This needs to stop here, but since Kent is saying that I don't 
understand, I'm going to reply.  Once.

We were talking about how a hypothetical airliner control system would 
have two different programs, written by different groups, running 
parallel, with either program capable of flying the plane.  Part of the 
flight system could crash that the pilots and passengers would not 
notice.  Airplanes in flight have to have controls that work in 
milliseconds without a glitch.

With MRO, we have Lockheed software doing navigation, but not "flying" 
the spacecraft.  JPL software flew the spacecraft, but did not 
navigate.  If JPL did their own redundant navigation, the error would 
have been caught.

It's not like they didn't have time, there was a week between the 
calculation and the burn.

The facts in the Wikipedia article are correct, it just doesn't describe 
a system that has any redundancy.

I will not comment further on this topic on list.  We're way over the 
limit on off-topic posts.

73 -- Lynn

On 1/17/2015 12:30 PM, KENT TRIMBLE wrote:
> Facts can also be factual.
>
> Kent  K9ZTV
>
> /<snip>/
>
> /_The primary cause of this discrepancy was that one piece of ground 
> software supplied by _Lockheed Martin 
> <http://en.wikipedia.org/wiki/Lockheed_Martin>_produced results in a 
> _United States customary unit 
> <http://en.wikipedia.org/wiki/United_States_customary_units>_("American"), 
> contrary to its Software Interface Specification (SIS), while a second 
> system, supplied by _NASA <http://en.wikipedia.org/wiki/NASA>_, that 
> used those results expected them to be in metric units, in accord with 
> the SIS. _Software that calculated the total impulse produced by 
> thruster firings calculated results in pound-seconds. The trajectory 
> calculation used these results to correct the predicted position of 
> the spacecraft for the effects of thruster firings. This software 
> expected its inputs to be in newton-seconds.^[16] 
> <http://en.wikipedia.org/wiki/Mars_Climate_Orbiter#cite_note-Mishap-17> /
>