Jello wrote:
t.
]
] Why the need to replace the Soyuz/Progress combo? Have there
] ever interruptions in Soyuz capsule production/launches?

The need to replace Soyuz is not schedule related, but instead derives from the following factors:

Crew Size - Soyuz can only support a crew of 3, limiting the number of crewmembers ISS can support. The thing was designed for a crew of 7-9, once crew assured rescue capability was added in the form of the Crew Return Vehicle (a concept that is being rolled into OSP)

Cargo Capacity - The Progress has 6.6 cubic meters of cargo space, limited to 3200kg of payload at the absolute top limit. Compare to the MPLM "moving van" that the Shuttle brings up on ISS logistic support flights, carries about 9 metric tons of cargo to the station. This, btw, is the one of the main reasons the ISS is limited to a crew of 2 until Return to Flight - the Progress cannot carry enough water to ISS to support 3 people.

Politics - You betcha. It outrages a great many people (and probably rightly so) that the US has paid Energia quite well for the Russian components of ISS, the Progress vehicles used to supply it, and the Soyuz vehicles used to man and provide assured return functions, and the price keeps getting steeper. Without going into too much detail, calling the Russians our "partners" definately requires quotation marks.

RE: Not So Fast, Lawmakers Say of Plans for a Space Plane