Space Probe In 1967
When "The Venus Space Probe" was returning to Earth, NASA discovered that it contained high levels of a strange and unknown radiation and decided to destroy it as it re-entered Earth's atmosphere. It was mentioned in the news report in Night of the Living Dead as Ben, Barbara, Harry, and Helen were watching it (as Tom and Judy were in a diffrent room). The strange radiation that the probe was carrying is speculated to have been the cause for the reanimation of the dead, although this was ultimately never confirmed.
Venus Probe Schematics