[amsat-bb] Re: Was HEO naivete; now GEO rideshare frequency choice, etc.

Nigel Gunn G8IFF/W8IFF nigel at ngunn.net
Mon Feb 9 12:17:38 PST 2009

Paul Williamson wrote:
> "The first burn went relatively well -- there was a small deviation from the expected burn duration, which placed the spacecraft perigee somewhat higher 
than planned. The second burn could not be accomplished because a slow leak in the high-pressure helium system during 
the week the spacecraft was being
reoriented prevented the opening of valves feeding fuel to the thrust assembly."
> The "small deviation" is known to be due to a design error in the simple digital logic circuit that controlled the burn duration.

OK. The helium leak was a propulsion system fault. The design error in the logic was human error and is known so can be 
designed out.

> On AO-13, the kick motor worked exactly as planned, and the spacecraft achieved the intended orbit. But that orbit could have been chosen better, 
as it turned out. The early re-entry after only 8.5 years was not anticipated, and probably could have been avoided if 
we had been smart enough,
soon enough.

Another "human error" Hindsight is wonderful.
I don't think we should reject an option that requires propulsion because of past errors that are now well understood.

Nigel A. Gunn. G8IFF   W8IFF (was KC8NHF)
1865 El Camino Drive, Xenia, OH 45385-1115, USA   937 825 5032
e-mail nigel at ngunn.net             www  http://www.ngunn.net
Member of  ARRL, GQRP #11396, QRPARCI #11644, SOC #548,  Flying Pig #385,
                   Dayton ARA #2128,  AMSAT-NA   LM-1691,  AMSAT-UK, MKARS,  ALC

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