Bill Ingalls/NASA/Getty Images Mikhail Kornienko, Gennady Padalka, and Scott Kelly (left to right) in front of a Soyuz spacecraft simulator. Kornienko and Kelly started a one-year tour of the space station last week.

For fifty years, NASA prepared for space missions as if for battle: practice repeatedly what you must do, prepare to be surprised, and have backup plans when you are, because you will be. But now with Americas space future at stake, that principle appears to have weakened, and NASA may have overlooked something crucial.

On March 4, during testimony before a U.S. House Appropriations subcommittee, NASA administrator Charles Bolden was asked about what happens if the Russians pull out of the International Space Station. (Critical ISS modules are Russian, and currently the only way for humans to travel between the ISS and the ground is via Russian Soyuz spacecraft.) Asked by the new chairman, John Culberson, about what would happen in the event that Vladimir Putins current belligerency ever led to Russia refusing to fly Americans to the space station, Bolden stated that it would be impossible for either Russia or America to operate the station without the other. Pressed by Culberson about NASA contingency plans, Bolden said You are forcing me into this answer, and I like to give you real answers, then adding I don't want to try and BS anybody. But, in the end, told the committee, We would make an orderly evacuation.

Thats itwed have time to pack and turn out the lights.

Thats the wrong answer. But Culbersons question was wrong too, narrowly focused as it was on Kremlin perfidy. Many scenarios could cripple Russias ability to fly crews to the ISS. The Russians could be victimized by technical problems with launch vehicles, suffer diplomatic problems with the Soyuz launch site (which is located in Khazakastan, a country concerned about whats been happening in Ukraine), be subject to terrorist attacks on ground infrastructure, or suddenly have to cope with age- or human-error-induced crippling of one of their station modules. Exactly what NASA and its other partners would have to do in response to any of these scenarios would deeply depend on the specific nature of the loss of function.

So to learn that NASA has spent no thought on what to do in the face of this wide gamut of possible events is disturbing. Past space disasterssuch as Apollo 13s liquid-oxygen tank explosion, Skylabs crippling launch mishaps, and the misshapen Hubble telescope mirrorwere overcome in large part because space planners had anticipated categories of failures and had then outlined response plans, albeit often with the details left to be filled in as needed.

But apparently not this time, with the most expensive and irreplaceable space station the world has ever seen? Let me suggest some half-baked answers as a starting point.

The problem of getting a US crew to the station is approaching resolution, with operational missions of commercial crew transportation vehicles from SpaceX and Boeing two or three years away. That date is budget-driven and with emergency funding could be moved significantly sooner.

Meanwhile, even if no new astronauts can be sent to the ISS, those already aboard would be able to hunker down and extend their stay significantly. It would bend and even break current medical limits (which have only recently been extended to permit a one-year stay on the station for Mikhail Kornienko and Scott Kelly, who blasted off for the ISS last Friday) but it would be an emergency response.

The remaining safety issue would be the problem of conducting anemergency evacuation in the case that one or both of the two Soyuz spacecraft normally docked at the station were unavailable. Even here, there are conceivable short-term modifications to existing cargo vehicles, such as SpaceXs Dragon capsule, that could provide an acceptable crew return ability with bare-bones life support.

More here:

What Happens If Russia Abandons the International Space Station?