The only thing preventing more Soyuz flights to ISS is that they haven’t been scheduled or payments arranged. I can’t imagine the Russians would be unhappy to provide significantly increased launch services to the “International Space Station”. There are plenty of launchers that can get more mass into space than the Shuttle can too – moving things off them onto or attached to the station would have to be done differently from the way it has been done with the shuttles, but it seems hardly likely a bunch of rocket scientists can’t come up with ways to do it with what we’ve got…

The only feature the shuttle has that cannot be readily duplicated on another existing platform is the ability to bring 20 tons or so of material back from space – on the other hand, it’s always seemed such a waste to put the effort into getting things (like the ESA’s Leonardo-class modules) up there, only to bring them back down again!

One of the links in the story said that there are “only two Soyuz capable of docking to the ISS.” I haven’t been able to verify this elsewhere on the net, although it says here that only some Soyuz are capable of docking with ISS.

It also says, “Specifically, the Soyuz can recover up to 100 lb of cargo while the Space Shuttle can recover in excess of 10,000 lb. However, both systems are dedicated to crew transfer and, in the case of the Space Shuttle, lead times to get on the cargo manifest is measured in years, if you can get on at all.” The payload you can bring back maybe isn’t vitally important, but it’s pretty useful when performing experiments that require equipment that must be brought back–and conducting zero-G experiments is supposed to be the main purpose for ISS, even if they haven’t been able to do much in that regard yet, due to being constantly short-staffed for lack of an escape vehicle that can carry more than three people.

There are (currently) only 2 Soyuz docking ports, which means only 2 of them at any given time. All the Soyuz are pretty much identical structure-wise, so that’s not the limitation (and they’re never re-used anyway, and only good for 6 months). More docking ports could easily be added; that was one of the options instead of creating an entirely new crew return vehicle. If necessary you could probably arrange some sort of tether system to strap extra Soyuz capsules to the station without being actually docked, but docking is obviously preferable.

Columbia was conducting a science mission that involved bringing a huge SpaceHab module up and back down to Earth. Given the cost of getting things to orbit, it would seem to make so much more sense to take the extra bit of effort to leave 10-ton human-habitable components in orbit, and conduct experiments in a way that either doesn’t require return, or for which a few hundred pounds of samples would suffice… Then the next time you go up, you have twice as much space to work with, no? Unfortunately, this stuff wasn’t designed with an eye to developing an orbital infrastructure, and was justified simply on the basis of the “science” being done. What we clearly need is a different over-riding purpose to our space efforts. Just doing it for science isn’t good enough.

Thanks for clearing that up for me.