The Waste of the Shuttle External Tanks

But to grasp just how far our current mindset is from being able to attempt innovation on such a scale, consider the fate of the space shuttle’s external tanks [ETs]. Dwarfing the vehicle itself, the ET was the largest and most prominent feature of the space shuttle as it stood on the pad. It remained attached to the shuttle—or perhaps it makes as much sense to say that the shuttle remained attached to it—long after the two strap-on boosters had fallen away. The ET and the shuttle remained connected all the way out of the atmosphere and into space. Only after the system had attained orbital velocity was the tank jettisoned and allowed to fall into the atmosphere, where it was destroyed on re-entry.

At a modest marginal cost, the ETs could have been kept in orbit indefinitely. The mass of the ET at separation, including residual propellants, was about twice that of the largest possible Shuttle payload. Not destroying them would have roughly tripled the total mass launched into orbit by the Shuttle. ETs could have been connected to build units that would have humbled today’s International Space Station. The residual oxygen and hydrogen sloshing around in them could have been combined to generate electricity and produce tons of water, a commodity that is vastly expensive and desirable in space. But in spite of hard work and passionate advocacy by space experts who wished to see the tanks put to use, NASA—for reasons both technical and political—sent each of them to fiery destruction in the atmosphere. Viewed as a parable, it has much to tell us about the difficulties of innovating in other spheres.

The tanks were allowed to burn up in the atmosphere, but for a slightly increased investment, they could have been left in orbit and used to build an even larger space station.