Mariner 9 Orbits Mars: First Spacecraft Maps Red Planet
NASA launched the Mariner 9 spacecraft toward Mars on May 30, 1971. It arrived on November 14 and became the first spacecraft to orbit another planet. Upon arrival, a global dust storm completely obscured the Martian surface, rendering the cameras useless. Project scientists waited two months for the storm to clear. When it did, Mariner 9 revealed a Mars far more complex than anyone expected: the enormous volcano Olympus Mons (three times the height of Everest), the Valles Marineris canyon system (ten times the length of the Grand Canyon), ancient river channels suggesting water once flowed on the surface, and layered polar ice caps. The spacecraft returned 7,329 images covering 85% of the planet before its attitude control gas ran out in October 1972.
May 30, 1971
55 years ago
Key Figures & Places
What Else Happened on May 30
Every tree within fifteen kilometres of Jerusalem. Gone. The Romans needed timber for their siege engines, and Titus didn't hesitate—ancient olive groves, orcha…
A tax collector named John Bampton demanded money from villagers in Brentwood, Essex—three times what they'd already paid. The men of Fobbing told him no. Just …
Jerome of Prague watched Jan Hus burn at the same council a year earlier, then recanted his own beliefs to save himself. Didn't work. He spent eleven months in …
English commanders stacked a tribunal with pro-English clerics to condemn Joan of Arc for heresy, violating ecclesiastical law by denying her legal counsel and …
Moderate Utraquist forces destroyed the radical Taborite army at Lipany, killing their leader Prokop the Great and ending twenty years of Hussite religious warf…
The rebellion lasted thirteen days. Prince Zhu Zhifan controlled China's northwest, claimed the throne his birthright, and commanded enough men to make Beijing …
Talk to History
Have a conversation with historical figures who witnessed this era. Ask questions, explore perspectives, and bring history to life.