JAMES OBERG: How risky is it to rely on Russian spaceflight?

The central lesson of the worldwide partnership that built the International Space Station has become clear. We have learned that multiple independent technologies for major space capabilities provide amazing robustness in the face of the unavoidable surprises. Whether for oxygen, or spacewalking, or crew access, redundancy can be crucial.

But now that lesson is being defied. The space station’s expedition crew members — including Russia’s Fyodor Yurchikhin and NASA’s Doug Wheelock and Shannon Walker, who are heading for the orbital outpost on Tuesday — will no longer be traveling back and forth on the soon-to-be-retired space shuttles. Single-string, critical-path capabilities are suddenly supposed to be “good enough.”

Well, it takes a while to repair the damage from decades of lousy policy.