Dangerous Development

For more than 10 years, space crews from the United States, Russia and other countries have successfully lived and worked year round, in six-month shifts, on the International Space Station, where they have conducted scientific research. In the coming years, that work will continue – but with a crucial safeguard missing: the space shuttle fleet that gives human beings a unique capability to fix the space station's guidance system and rocket thrusters in the event of a terrible failure.

The shuttles are now about to retire – all of them, with no true replacements. This is an extremely dangerous development.

Loss of control of the space station would mean a catastrophic reentry into the Earth's atmosphere of the massive structure – the largest object ever placed in orbit around the Earth, measuring over three football fields long and weighing more than 400 tons.

The tons of falling debris that would survive reentry would pose an unprecedented threat to populated areas around the world.

Such an international catastrophe would have significant ramifications for foreign relations and liability for the United States, Russia and the other countries who participate as partners on the space station.

To be sure, the space station has numerous, triple-redundant life support and control systems that makes such a total technical failure unlikely. However, to say that it is so redundant that it could never happen ignores the tragic lessons learned due to the overconfidence in fail-safe technology in disasters throughout history, from the sinking of the Titanic to the nuclear reactor crisis in Japan.

In fact, the numerous space station backup systems offer little margin of safety in the event of damage from a fire, space junk impact or a potential collision from the more frequent docking of manned and unmanned commercial spacecraft resupply missions.

If the life support, guidance systems or rocket thrusters are damaged, the station could need a rapid rescue mission to stay in orbit. And as repair vehicles, the space shuttles have unique capabilities.

It's true that pallets on the space station are packed with spare parts needed for critical repairs, but none of them could be installed to repair and regain control and use of the $100 billion space station if it is deemed uninhabitable for repair crews. In that case, an independent repair spacecraft will be needed. And the Russian Soyuz space capsules and other commercial space capsules that are intended to replace the space shuttles lack the life support systems needed for the multiple six-hour repair spacewalks.

Only the space shuttles have the vital airlocks and life-support supplies – as well as the robotic arm that is needed to move the hardware necessary for the required two-person spacewalking repair crews.

Before the last scheduled shuttle flight lifts off early next month, an urgent discussion needs to take place between the United States and its International Space Station partners to keep the shuttle fleet in service to provide a vital safety margin for repairing the space station in the event of a critical systems failure.

In fact, to prevent any gap in this crucial repair capability, we urge NASA to delay the last shuttle launch so that additional external fuel tanks and other parts can be built to support additional shuttle flights in 2012.

We also request that Congress hold hearings on this matter. The space shuttle fleet provides the only insurance against a catastrophic reentry of the space station. With such valuable equipment in orbit – and the dangers should that equipment fall to Earth – it is never wise to play Russian roulette in space.

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