What was exposed by the Columbia accident was not the inherent dangers of a Shuttle flight, which are fairly obvious, but the vulnerability of our current space program to the loss of a vehicle.

When the X-33 was scrapped, and it became clear that we were going to be flying Shuttles into the indefinite future, the orbiter fleet was the critical failure point of our entire manned space program.

There were four orbiters. A fifth was cobbled together from spares to replace the Challenger, but it was evident that it would be almost impossible to build another one. Now there are three. Eventually, given enough flights, there will be fewer.

At least NASA has finally recognized that we need an alternative for manned space transportation, but this was obvious to most of us for the past ten to fifteen years. And after the X-33 fiasco, I'm not sure what to expect from the OSP, other than a constant flow of money to hundreds of contractors, which in my more cynical moments, seems sometimes to be more important than actually getting something to work.

I must admit that having worked on a cheap, workable, off-the-shelf alternative to ISS support (with a manned capability), then having it tossed out by NASA, may color my views a bit.