Launch Date: November 3, 1973 🇺🇸 (NASA) Planetary Society
A New Chapter in Planetary Exploration
Just months after Pioneer 11’s launch, NASA sent Mariner 10 into space. It became the first mission to use a gravity assist maneuver, flying past Venus before heading to Mercury—and making three close flybys of Mercury between 1974 and 1975. Time and Navigation+3Wikipedia+3HISTORY+3
Mission Objectives
- Fly by Venus to adjust trajectory via gravity assist
- Conduct three Mercury flybys, mapping the planet’s surface and studying its magnetic field and solar environment
- Test dual-planet mission design and advanced imaging instruments
Key Moments & Discoveries
- Venus Encounter: February 5, 1974 – first up-close photos of Venus, including chevron cloud formations Facebook+5WIRED+5WIRED+5Wikipedia
- First Mercury Flyby: March 29, 1974 – passed just ~440 mi (700 km) from Mercury, capturing its first close-up images and detecting a weak magnetic tail Wikipedia+15WIRED+15Wikipedia+15
- Subsequent Flybys: September 21, 1974 and March 16, 1975 brought new surface imagery and magnetic measurements WIRED
Legacy
Mariner 10 flew past two planets, demonstrating the power of gravity-assist navigation and capturing about 35% of Mercury’s surface—laying groundwork for later orbiters such as MESSENGER. This mission set a new paradigm for planetary exploration. HISTORY+2
