Cutting the ISS in half.

In sci.space.station message , Wed,
27 May 2009 08:55:10, David Spain posted:
John Doe writes:
If the USA does have some Orion vehicle with some propulsion capability,
then it might be able to act as a propulsion system fior the ISS if
there is always one there. Would probablly require the station be turned
180" so that the russian segment would be up front with the US Orion at
PMA2 in the back to push the station.

It's not clear to me at all that the current proposals for docking
adpaters for Orion
would be up to this task. Can anyone enlighten us?

Currently, I calculate the mean drag to be 0.13 Newtons, about the
weight of a slice of apple for the metrically-challenged -
http://www.merlyn.demon.co.uk/gravity2.htm#EDOB.

A docking adapter must be approximately half a square metre in area, at
least, for crew transit, and the pressure inside is 100 kPa, so the pop-
apart force is at least 50 kN.

I'd expect anything that can stand 50 kN push-apart to be easily able to
be designed to withstand at least 5 kN in any direction.

So, to correct for mean drag, it would be necessary to push at 5 kN for
one part in 35000 of the time; about 2.5 seconds per day; under five
minutes per quarter-yearly visit.

Therefore, provided that Orion is equipped with a suitably small
thruster set pointing in the right direction, there should be no
difficulty. It seems within the ball-park of the thrusters that might
be used for docking and undocking.

Check those figures.

ISTM also that the mean drag of 0.13 Newtons could be continuously
compensated, in the manner of GOCE, with a small number of ion engines
driven from available power, at easily-provided fuel consumption.

--
(c) John Stockton, nr London, UK. Turnpike v6.05 MIME.
Web URL:http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms & links;
Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc.
No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News.

The question of cutting the ISS in half was brought up at the press
conference.

Russia's plan is to have constant presence of man in space. Russia has
no plans to undock the US segment, its goal is to extend the life of the
station. This is in relation with a contigency plan where contracts are
not renewed.

The rumour of cutting ISS in half was apparently created by Anatoly Zak.
(his name was mentioned by russian officials).

Individuakl countries have to decide if their equipment can have its
life extended. For instance, Canada need to study if its hardware on teh
station (arm, base, dexter) will have a useful life beyond the existing
contract, and what contigencies would exist to send spare parts without
a shuttle.

John Doe wrote:

The rumour of cutting ISS in half was apparently created by Anatoly Zak.
(his name was mentioned by russian officials).


Here's Zak's website, BTW: http://www.russianspaceweb.com/


Pat