Planetary Protection

In the 1969 novel “The Andromeda Strain,” microbes from beyond Earth attach themselves to an orbiting satellite. When the satellite returns to Earth, the microbes kill several people and threaten everyone on the planet. A special team of scientists is called in to save the day.
Real scientists are pondering similar scenarios. They’re looking at how to protect Earth from possible microbes from Mars and other worlds — and to protect those worlds from Earthly germs. Many of those scientists are meeting in Houston this week to discuss their work.
NASA already takes steps to protect other worlds from contamination. When the Cassini mission to Saturn was ending, for example, the craft was destroyed by having it plunge into Saturn’s atmosphere. That kept it from accidentally hitting some of Saturn’s moons, which could be homes for microscopic life. And some possible landing sites for the Curiosity Mars rover were ruled out because they were spots where microbes might be found — or where mi