If control is lost during the Earth flyby, a crash into the atmosphere might scatter some of the plutonium to the winds.
Another Earth flyby within 11,000 km occurred on June 19, 2003.
Even under the best conditions, we couldn't afford to run three crew members short for the Earth flyby.
Since the Earth flyby, though, some strange, unspoken consensus had been reached that the doors would mostly remain open.
The second Earth flyby occurred on November 13, 2007.
The spacecraft used the gravity of Mars to change course towards its second Earth flyby in November.
Another Tempel 1 preparation task is to image the moon at 55 hours before closest approach during the Earth flyby.
The spacecraft will then be left alone until after Earth flyby.
After two Earth flybys, lunar insertion was achieved approximately one month after launch.
In 1999 Giotto made another Earth flyby but was not reactivated.