Mariner 10
November 3, 1973

  Assembly and liftoff
Assembly and liftoff

The last of the Mariner series, Mariner 10 launches with a two-planet objective: Mercury and Venus.

For the first time, engineers experiment with an ingenious way of traveling through the solar system using the gravity of one planet to help propel the craft on to the next destination -- somewhat like a series of bank shots in a game of billiards. With Mercury as its ultimate target, Mariner 10 pioneers the use of a "gravity assist" swing by the planet Venus to bend its flight path toward Mercury.

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