Herb Schaltegger writes:

On Wed, 24 Aug 2005 08:04:34 -0500, Jochem Huhmann wrote
(in article ):

Herb Schaltegger writes:

Here, elucidate us, Monsieur Mezei: spell out all the modifications
that would have to be made to carry Columbus on Ariane V. In detail.

While it's certainly true that there's no way to launch truss segments
with ATV I'm not so sure about Columbus. ESA *did* consider launching
Columbus on Ariane V in the past and I've read statements from someone
at ESA that this is still reflected in the design of the module and
launching on Ariane would require no major modifications.

If you've ever seen a spacecraft launcher ICD, you'd realize someone at
ESA's equivalent of a Public Affairs Office is talking out of his ass
in order to placate people who don't know better.

Found it. It wasn't someone from Public Affairs but an ex-ESA-astronaut,
obviously not that good informed...

The Orbiter has a very specific, defined set of interfaces and
environments, not the least of which is a set of trunnion pins for
load-carrying. To launch any existing ISS modules on another booster,
you'd essentially have to build an aeroshell that duplicates those,
plus has a matching thermal, acoustic and vibrational environments.
Basically you'd have to build an orbiter payload bay and stick it on
top of the booster, just for the physical interfaces. And that doesn't
replicate the vibrational, acoustical and thermal environments. All
the existing modules and segments have, since day 1, been designed,
built, tested and qualified for flight with those requirements in
mind.

Yeah, well. The point was that if the module had initially been designed
to being launched on Ariane in the first place, changing it back to this
would have been a bit simpler. If not, you'd be better off building a
new module from scratch, no doubt.

And once the module is in orbit, it still has no self-contained ability
to rendezvous and dock (berth, really) to ISS.

Yes, that was what I meant with "useless". Launching a module you can't
attach to the station makes not that much sense.

Mezei handwaves around the acronym "ATV" like it's some magic space
tug when it reality it's nothing of the sort.

Well, it is a space tug of sorts. Not a magic one, granted.

I can't find the source of that yet and of course I have no details.
Still, it might be not so impossible as it seems. If it would make
any sense is another question.

If ESA wanted to spend a few billion Euros and maybe 5 - 8 years, it
might be do-able. It certainly wouldn't be easy or inexpensive.

Looking at what has already been developed for Columbus and ATV, needing
8 years and a few billion Euros for some kind of Ariane-launched
ATV-tugged Columbus-like module seems a bit heavy to me. And anyway,
if NASA should prove to be unable to deliver Columbus, ESA is probable
in a good position to nudge NASA into paying quite a bit of that...


Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take away."
- Antoine de Saint-Exupery