Two spacecraft crashed into the moon
In 2011, NASA launched two spacecraft to study the moon. Those two craft ended their missions by crashing into the moon yesterday.
The two spacecraft, Ebb and Flow orbited for over a year mapping out the gravitational field of the Moon. NASA scientists used the data to get a better idea of the interior make-up of the moon.
The spacecraft Ebb and Flow had to constantly adjust their speed and trajectory to stay in lunar orbit because the Moon’s gravitational field is not as reliable and consistent as the Earth’s. The adjustments used fuel and if the fuel ran out NASA could not control where the craft would crash. So they decided to use the remaining fuel to set a course that caused the two craft to crash in a safe zone in the lunar north pole.
The two craft crashed into a mountain on the Moon 30-seconds apart, yesterday afternoon around 4:30 PM.
Space historian Robert Zimmerman says it is fairly common for NASA to dispose of spacecraft this way. The controlled destruction allowed NASA to protect historical lunar sites, like the landing zones for the manned Apollo missions.