|We could estimate that 89% of all spacecrafts
has successfully accomplished their missions and 11% has failed.
Of the 6,854 spacecrafts launched between 1957 and 2009, some 732 had failed.
(See Table 6 - Success and Failure Ratio and
the list of Spacecrafts (known) Failures.)
Of these failed spacecrafts, nearly two-third
occured at launch, one percent were lost before launch (pad accidents),
one-eighth shortly after reaching orbit, one-sixth while performing their
missions and one-twentieth at the end of their mission.
(See Table 7 - Spacecrafts