Re: Dumping the Shuttle

Derek Lyons wrote:

> No. An *alternate path* saved A13.  A set of reactant tanks in
> another SM bay would have been redundant, a honkin' big battery
> would have been backup equipment, the LM was an alternate path.
> 
> The first two terms are tossed about with some abandon, but
> they are not synonyms.

I pretty much agree.  And going by memory, they did add an extra 
tank or tanks to Apollo 14, although I couldn't find a reference to 
that quickly so that may be incorrect.  Also, by memory, they put 
the tank in a different location.  Physical proximity and damage 
influenced the design of the Shuttle's computer complex, just a 
random bit of worthless trivia.  I don't recall anything about a 
beefed up battery or extra batteries.

This was how the redundancy/alternate path thing was viewed at the 
time.  Here's part of a memorandum, perhaps this is a bit in the 
gray area, as this memorandum mixes in the terms "redundancy" and 
"alternate paths."

   While there is no need for us to file a separate lengthy report,
   we would like to emphasize certain points.

   The total Apoll system, both hardware and software, possesses a
   considerable degree of inherent redundancy and reliability.
   Successful return to earth after a major system failure was
   possible because many alternate systems, modified procedures,
   and non-standard operations were available to the ground and
   flight crew.

   Almost all of the special actions and procedures required for
   a successful recovery had been thought out and developed in
   the pre-mission period.  This says much for the thoroughness
   of mission planning.

   ...

Memorandum from Charles D. Harrington, Chairman, ASAP, to Dr. T.O. 
Paine, Administrator, NASA, June 25, 1970, included as an Appendix 
to the Second Report of the ASAP.

-- 
rk, Just an OldEngineer
"In God we trust, all others bring data." 
-- Framed plaque from the '60s, hanging in the Mission Evaluation
   Room at Johnson Space Center, downstairs from Mission Control.