wrote in message
...
On Feb 16, 12:32 pm, Brian Thorn wrote:
On Sat, 16 Feb 2008 09:39:48 -0600, "Joseph S. Powell, III"

wrote:
With all the excitement experienced during the past few days with the
attachment of the Columbus module to the ISS, I was reminded of the
types of
Space Station modules proposed back in the 1980's....
These tended to have a longer design, filling up the entire payload bay
of
the Shuttle.
Does anyone know why these longer modules were rejected in favor of the
shorter ones now used on the ISS?

The Kibo Lab is the same dimensions it has always been planned to be.

The U.S. modules shrank in a cost-cutting move during one of the
redesigns in the early 1990s (this happened before the Russians came
aboard and the inclination changed, so it wasn't because of that.)

Columbus uses the MPLM spaceframe, probably as another cost-saving
move. The MPLM was sized that way to leave room in the payload bay for
non-pressurized cargo, if necessary.

Brian

The first "M" in MPLM used to be for Mini. It was another cost saving
measure. The original PLM were bigger

Wikipedia doesn't agree (but it's obviously not the best source):

The MPLM was originally designed for Space Station Freedom. Initially,
it was to be built by Boeing, but in 1992, the Italians announced that
they would build a "Mini-Pressurized Logistics Module," able to carry
4500 kg of cargo. After the 1993 redesign, the length was doubled and
it was renamed the "Multi-Purpose Logistics Module." Each empty MPLM
is approximately 21 feet (6.4 m) long, 15 feet (4.6 m) in diameter,
weighs 4.5 tons, and can deliver up to 10 tons of cargo to the ISS.

Spaceref seems to agree with you:

Note: the acronym "MPLM" used to stand for "Mini-Pressurized Logistics
Module". During the various space station redesigns in 1992/1994 various
modules were reduced in size to save weight. The Space Station Freedom
program's larger PLM (Pressurized Logistics Module) was reduced in size
and dubbed the "mini" PLM. The acronym stuck, but as the program evolved,
the original name did not.

Astronautix.com (article by Marcus Lindroos) doesn't agree:

When the International Space Station (ISS) was redesigned again in 1993,
it was decided to expand the original Mini-Pressurized Logistics Module
design. The new Multi-Purpose Logistics Module was twice as long and
could carry 9000 kg of cargo to ISS.

It almost seems like there was a Pressurized Logistics Module which got
shortened to a Mini-Pressurized Logistics Module, but the Mini-Pressurized
Logistics Module was then doubled in size to the Multi-Pressurized Logistics
Module. If true, this begs the question, is the current MPLM bigger,
smaller, or the essentially the same size as the original PLM?

Jeff
--
A clever person solves a problem.
A wise person avoids it. -- Einstein