Chris J. wrote in
:

On Sat, 20 Aug 2005 12:37:15 -0500, Brian Thorn
wrote:

On 20 Aug 2005 08:50:18 -0700, wrote:

What is the point of building a human access means to LEO which will be
operational in the 2010s ... could someone explain to me what is the
mission... what is the need ?

International Space Station. The US isn't backing out until 2015
(pretty much the 15 years agreed to in the first place) and there is
little reason to believe ISS will fall into the sea as soon as the US
pulls out.

I'm clearly missing something here; Why is the US pulling out after
ISS completion? Isn't that analogous to spending decades and billions
to build a laboratory, and then withdrawing right as it actually can
begin full research operations?

In other words, why bother to build it in the first place under this
scenario? And more to the point, why bother continuing construction?
What am I missing here?

What you're missing (besides the politics) is the timeline. The shuttle
orbiters will be retired in 2010, at which time ISS assembly will be
declared "complete". The US will remain in the ISS program until 2016 (not
2015). So the US isn't withdrawing right after assembly complete; it will
continue using ISS for six years.

ISS has a design lifetime of 15 years. Depending on when you consider the
"clock" to have started, that could expire as early as 2013 (FEL+15) or as
late as 2015 (PMC+15). That doesn't mean that ISS will immediately become
unusable after that point, but it *does* mean that the components will be
exceeding their rated lifetimes, and will start failing at a higher rate.
At that point, maintaining ISS will become progressively more expensive.
The US has consciously decided not to remain a party to ISS after that.

--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.