[Elecraft] Buggy software OT

[Phil Wheeler]

I wonder if the design not being done to spec
/
//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),/

qualifies as a "bug" -- vs. a design mistake?

Phil W7OX

On 1/17/15 12:30 PM, KENT TRIMBLE wrote:
> Facts can also be factual.
>
> Kent  K9ZTV
>
>
> /On November 10, 1999, the Mars Climate Orbiter 
> Mishap Investigation Board released a Phase I 
> report, detailing the suspected issues 
> encountered with the loss of the spacecraft. 
> Previously, on September 8, 1999, Trajectory 
> Correction Maneuver-4 was computed and then 
> executed on September 15, 1999. It was intended 
> to place the spacecraft at an optimal position 
> for an orbital insertion maneuver that would 
> bring the spacecraft around Mars at an altitude 
> of 226 kilometers on September 23, 1999. 
> However, during the week between TCM-4 and the 
> orbital insertion maneuver, the navigation team 
> indicated the altitude may be much lower than 
> intended at 150 to 170 kilometers. Twenty-four 
> hours prior to orbital insertion, calculations 
> placed the orbiter at an altitude of 110 
> kilometers; 80 kilometers is the minimum 
> altitude that Mars Climate Orbiter was thought 
> to be capable of surviving during this maneuver. 
> Post-failure calculations showed that the 
> spacecraft was on a trajectory that would have 
> taken the orbiter within 57 kilometers of the 
> surface, where the spacecraft likely 
> disintegrated because of atmospheric stresses. /
>
> /_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> 
> /
>
> //
>
> /The discrepancy between calculated and measured 
> position, resulting in the discrepancy between 
> desired and actual orbit insertion altitude, had 
> been noticed earlier by at least two navigators, 
> whose concerns were dismissed. A meeting of 
> trajectory software engineers, trajectory 
> software operators (navigators), propulsion 
> engineers, and managers, was convened to 
> consider the possibility of executing Trajectory 
> Correction Maneuver-5, which was in the 
> schedule. Attendees of the meeting recall an 
> agreement to conduct TCM-5, but it was 
> ultimately not done./
>
>
>
> On 1/17/2015 1:41 PM, Lynn W. Taylor, WB6UUT wrote:
>> Good quip, but it doesn't agree with the 
>> findings of the Mars Climate Orbiter Mishap 
>> Investigation Board.
>>
>> Facts can be so inconvenient.
>>
>> On 1/17/2015 11:15 AM, KENT TRIMBLE wrote:
>>> Good quips always sail over at least one 
>>> person's head.
>>>
>>> K9ZTV