[sci.space] Chariots for Apollo #5 - Scrape & SWIP

dcn@ihuxl.UUCP (Dave Newkirk) (10/17/86)

The lander had gained even more weight during the early months of the
year [1965] than the command and service modules.  In May, Shea pursuaded
Mueller to approve an increase in lander weight to 14,850 kilograms,
including crew and equipment.  In June, Harry L. Reynolds warned Owen
Maynard that it would be difficult to keep the spacecraft below even
that figure. ...  Really worried now, Grumman launched a two-pronged
attack known as "Scrape" and "SWIP".  Scrape meant just what the word
implies, searching the structure for every chance to shave bulk off
structural members.  But SWIP (Super Weight Improvement Program) was
Grumman's real war against weight. ...

By the end of 1965, Scrape and SWIP had pruned away 1100 kilograms,
providing a comfortable margin below the control weight limit. One
of the more striking changes to come from this drive for a lighter
spacecraft was the substitution of aluminum-mylar foil thermal blankets
for rigid heatshields.  The gold wrapping characteristic of the lander's
exterior saved 50 kilograms.

Many of these weight-reducing changes made the lander so difficult to
fabricate, so fragile and vulnerable to damage, that it demanded great
care and skill by assembly and checkout technicians.  Structural compo-
nents took on strange and complex shapes, requiring careful machining
to remove any excess metal - a costly and time-comsuming process even
after vendors had been found who would make these odd looking parts.*

* Arnold Whittaker described how the fabrication group was caught in
the squeeze between manufacturing requirements and schedule pressures.
At a program management meeting he said that "one of the fellows in
manufacturing came in [with] a light cardboard box. . . He said `I'll
show you why everything's late.`  And he dumped out a whole box of
machined parts . . , very complex fittings [too thin to be even]
reasonably heavy sheet metal - but it wasn't any sheet metal, it was a
complex machined fitting.  And he said `Man, we never built parts like
this before in any quantity like this and every fitting on the LEM looks
like this.`"

------------------------------------------------------------------------
From "Chariots for Apollo: A History of Manned Lunar Spacecraft", NASA
SP-4205, available from the Superintendent of Documents, U.S. Government
Printing Office, Washington, DC 20402, stock number 033-000-00768-0.
-- 
				Dave Newkirk, ihnp4!ihuxl!dcn