Editing Mariner program (section)

==Mariner 10==
{{Main|Mariner 10}}
[[Image:Mariner 10.jpg|150px|thumb|Mariner 10]]

The [[Mariner 10]] spacecraft launched on November 3, 1973, and was the first to use a gravity assist trajectory, accelerating as it entered the gravitational influence of Venus, then being flung by the planet's gravity onto a slightly different course to reach Mercury.<ref name="NASA"/> It was also the first spacecraft to encounter two planets at close range, and for 33 years the only spacecraft to photograph Mercury in closeup.

Here a fortuitous gravity assist enabled the spacecraft to return at six-month intervals for close mapping passes over the planet, covering half the globe (Mercury's slow rotation left the other half always in the dark when Mariner returned).<ref name="NASA"/>
* Mission: plasma, charged particles, magnetic fields, radio occultation and celestial mechanics
Status: Mariner 10 – Defunct and now in a [[heliocentric orbit]].