So why are they letting Mir drop back to Earth? Wouldn’t it be useful to bring it to the International Space Station and connect them?. I mean, at the very least, it would mean an additional several tens of cubic feet of work space volume at relativelty low cost compared to having to lift the same size space from the surface. Any comments?
Ev
'Cause it’s a pile of junk?
My guess would be that it would be similar to hauling that old mobile home over to your brand new house and connecting it up. Sure you get more square-footage, but the old part will require a lot of upkeep, and could detract from the value and/or safety of the new part.
It’s my impression that Mir is basically worn out. It has already outlasted its projected life by quite a few years. The power and life support systems have reached the end of their utility and the ISS does not have the extra capacity required to supply the additional volume. I suppose they could attach Mir to the ISS with an interlock of some sort and use it as the first orbiting pole barn. That’d merely require the astronauts to use space suits when entering it.
I don’t think it would be a good idea to merge the two stations for reasons previously suggested, but since both can dock a Soyuz spacecraft, one would think it would be fairly easy to build a Soyuz hatch-shaped connection tube to do the job.
Physically mating them together, i.e. mechanical connection, would be easy. They both have the same docking mechanisms. However, that wouldn’t provide any hookups between other systems - like cooling, air recirculation, oxygen supply, electrical connections. Then you have to figure out all the inertial properties to affect a good reboost. Plus make sure you have large enough thrusters, have them synched up, have enough fuel, etc.
Then there’s the geometry of the combination - will componenets overlap, like solar arrays and radiators. The geometry of ISS is layed out and sequenced so it has certain amounts of the above and the geometry builds sequentially so it can take care of itself. Adding MIR to ISS would prove cumbersome, and definitely throw out all the work in planning to date.
Add to that the fact that most of the MIR systems are 12 years old or older and are not holding up well (anybody remember Michael Foale?), and you’re talking a bad idea. Though I have heard rumors of the Russians wanting to take some of their newer MIR modules over to ISS, but don’t think the U.S. ever liked that plan.
Plus Mir’s got that evil space fungus growing all over inside of it right now. No doubt that no matter how hard the astronauts keep up with their housework ISS will probably develop its own flora after a few years. Mir probably smells pretty rank nowadays too. Yuck. Good thing a stuffy nose is one of the side effects of weightlessness. 
Space fungus???
It’s not exactly extraterrestial, but some earthbound fungi hitched a ride on a Soyuz or got inside before Mir itself was launched and found Mir to be a lovely environment to grow. Its been found on earlier Russian space stations as well.
http://www.space.com/news/spacestation/space_fungus_000727.html
Still want to try out for Survivor Mir?
Thanks for the info folks! I read that article on the fungi. Pretty scarry. Aspergillus is a potentially harmful organism to humans to add a wrinkle to the story.
Ev
The ISS project is already planned out/in-place. It’s too late to make huge modifications now.
The internal communications is very complex for the ISS and goes through extensive testing. This is used to control every aspect of the Station, heating, cooling, lighting, experiment bays, communication, everyting that happens on the Station. No way at this point could the MIR ‘fit’ into the plan with it’s obsolete and completely different communications. Also adding something like this would change the center of mass for propulsion to keep it in orbit.
later, Tom.
It has nothing to do with hardware compatibility, or the other silly reasons that have been presented, but with celestial mechanics. In order to dock, two objects must orbit in the same plane with respect to the object they orbit.
It is possible to change the plane of an orbiting object, but it is expensive in terms of “deltaV”. That’s why there is a short launch window each day which ships to any spacestation must use. Outside that window, and the amount of fuel needed to make the orbits “co-planar” becomes prohibited.
Because the Russian space center has only had enough capacity to communicate with one station at any given time, even though they have the same orbital inclination (about 57degrees), the new station was deliberately placed as far from the plane of Mir as possible, at almost right angles.
I forget the details, but I seem to remember someone in a space newsgroup saying because of this difference, it would take the equivalent of several Saturn V launches to bring the two together. Not physically impossible, but not worth the effort.