USA · NASA/Amesfirstrobotic
March 3, 1972
Pioneer 10 launches — first probe to Jupiter and through the asteroid belt
Just before nine in the evening on 2 March 1972, Florida time, an Atlas-Centaur with an added solid third stage tore off the pad at Cape Canaveral carrying a 258-kilogram spacecraft no bigger than a small car. Pioneer 10 left Earth at 51,682 kilometres per hour, faster than any human-made object before it, crossing the Moon's distance in about eleven hours. Its destination was Jupiter, a world no spacecraft had ever approached, on the far side of a region many scientists genuinely feared would destroy it.
On 15 July 1972 Pioneer 10 entered the asteroid belt, and for the next seven months it threaded roughly 435 million kilometres of space that mission planners could only hope was mostly empty. Nobody knew the true density of small debris; some predicted the spacecraft would be sandblasted to death. It emerged in February 1973 essentially unscathed, retiring one of the great unknowns of deep-space flight and opening the outer solar system to everything that followed.
On 4 December 1973, Pioneer 10 swept within 130,354 kilometres of Jupiter's cloud tops, returning the first close-up images of the giant planet and direct measurements of its ferocious radiation belts and vast magnetic field. Jupiter's gravity then slung the spacecraft outward on a trajectory that would carry it out of the solar system entirely, the first machine ever placed on an interstellar escape path.
Bolted to its antenna struts rode a gold-anodized aluminium plaque, conceived by Carl Sagan and Frank Drake and drawn by Linda Salzman Sagan: a man and a woman, a map of the solar system, and the spacecraft's home located against 14 pulsars. Designed for a 21-month mission, Pioneer 10 transmitted for over three decades; its last faint signal reached Earth on 23 January 2003 from 12.23 billion kilometres away. It now coasts silently toward the star Aldebaran, a journey of some two million years.
Mission Data
Launch
3 Mar 1972, 01:49 UT (2 Mar EST), Cape Canaveral
Spacecraft mass
258 kg
Departure speed
51,682 km/h, fastest human object to date
Jupiter closest approach
4 Dec 1973, at 130,354 km
Asteroid belt crossing
15 Jul 1972 – Feb 1973
Last signal received
23 Jan 2003, from 12.23 billion km
Key Facts
Before Pioneer 10, no one knew whether a spacecraft could survive the asteroid belt; some scientists predicted it would be destroyed by debris. It crossed in seven months without serious damage.
It left Earth at 51,682 km/h, the fastest any human-made object had ever travelled, passing the Moon's distance in roughly 11 hours.
The famous plaque, showing a man, a woman, and a pulsar map locating Earth, was conceived by Carl Sagan and Frank Drake, with the figures drawn by Linda Salzman Sagan.
Designed for a 21-month mission, it kept transmitting for almost 31 years; the last signal arrived in January 2003 from 12.23 billion kilometres away.
It is now coasting toward the star Aldebaran in Taurus, a crossing that will take on the order of two million years.
Why It Mattered
Pioneer 10 opened the outer solar system. By surviving the asteroid belt it removed the single biggest perceived barrier to exploring beyond Mars, and by mapping Jupiter's radiation environment it gave the Voyager designers the data they needed to harden their spacecraft for the Grand Tour. It pioneered nuclear-powered deep-space operations far from the Sun, proved gravity assists could fling probes onto escape trajectories, and became humanity's first emissary to interstellar space. The plaque it carries reframed spaceflight itself, recasting a physics experiment as a message from one civilization to whoever, someday, might find it.
NASA / Ames Research Center
Official source
