When 60-minute hysteria nearly brought down a NASA mission to Saturn


Few impediments could have been more serious. In order for a spacecraft to reach the Jovian system fast enough to finally achieve orbit around Europa, it had to launch from a powerful rocket (which NASA lacked, which limited the spacecraft to space shuttle deployment) or be absurdly light (which the required radiation armor made impossible). JPL engineers were quick to write equations in chalk before throwing fists at the slates in fits of desperation.

Nothing for NASA was ever free … except for gravity aids. Typically, the agency could compensate for the meager speeds of heavy spacecraft by taking indirect flight paths and using planets encountered along the way to pull and push the robotic pilgrim out, in, or forward. With the laws of physics immutable, and the outstanding numbers known, NASA’s orbital dynamists could do this all day, running the numbers to launch spaceships with precision, from one planet to the next: Isaac Newton’s free propulsion. It was incomparably the best deal in space exploration.

But then tabloid television journalism got involved and things got complicated.

In 1997, while waiting at Cape Canaveral for takeoff, the Cassini mission was suddenly beset by political protests. Cassini carried three radioisotope thermoelectric generators, which worked on the decay of plutonium 238. The plutonium was not of the type Return to the future variety, an eerie drop of Scary Substance Indeed on a homemade flux capacitor, but instead was stored in ceramic form, wrapped in iridium and coated in graphite. It could not corrode, be destroyed by heat, vaporize, disintegrate as an aerosol, or dissolve in water. It was made to withstand not only the explosion of the rocket carrying it, but even a catastrophic reentry into the Earth’s atmosphere. Because it couldn’t vaporize, in a disaster situation, no one would inadvertently inhale it and develop additional superpowers or appendages. In fact, it was designed so that you could even eat the things. The human body could not absorb it.

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