Dec. 3, 1973: Pioneer 10’s jovian flyby

Pioneer 10 sent a series image of Jupiter back to Earth on Dec. 4, 1973, the planet growing and then receding as the spacecraft approached and completed its flyby. Credit: NASA

Key Takeaways:

• Launched on March 2, 1972, Pioneer 10 became the fastest human-made object to depart Earth's vicinity, reaching speeds of 51,500 km/h and traversing the Moon's orbit within its first half-day of flight.
• The probe carried a comprehensive array of scientific instruments, including detectors for plasma, charged particles, cosmic rays, and radiation, alongside infrared/ultraviolet scanners and an imaging photopolarimeter; it was also the first nuclear-powered deep-space mission, utilizing four plutonium generators.
• After a 641-day journey, on December 3, 1973, Pioneer 10 performed a close approach to Jupiter, passing approximately 132,253 kilometers above the planet's cloud tops.
• The mission's data revealed Jupiter as a dynamic, "colorful, stormy world" characterized by distinct latitudinal belts and zones, profoundly impacting scientific understanding of the gas giant's physics and chemistry.

Key takeaways sponsored by The Space Store

When its Atlas Centaur rocket rose from Cape Canaveral’s Launch Complex 36A at 8:49 P.M. EST on March 2, 1972, Pioneer 10 started knocking down records right off the bat. It became the fastest human-made object to leave our planet, barreling away from Earth at 32,000 mph (51,500 km/h) and passing the Moon within its first half-day of flight. The craft was brimming with detectors for plasma and charged particles; cosmic-ray and Geiger-tube telescopes; asteroid, meteoroid and radiation sensors; infrared and ultraviolet scanners; an imaging photopolarimeter; and a magnetometer. To provide power in a realm where sunlight grew progressively weaker, Pioneer 10 carried four plutonium generators as the world’s first nuclear-powered deep-space probe.

After traveling for 641 days, at 9:25 P.M. EST on Dec. 3, 1973, the probe swept just 82,178 miles (132,253 kilometers) above Jupiter’s cloud tops to reveal a colorful, stormy world of striking latitudinal belts and zones of vivid reds, creams, and browns. Forty-six minutes later, its first data reached the eyes and ears of the Pioneer 10 team at NASA’s Ames Research Center in California. “So deluged were Pioneer scientists with transmissions of the spacecraft’s instruments,” opined the Washington Post, “they were literally changing their minds about Jupiter’s physics and chemistry every hour.”