June 13, 1983: Pioneer 10 Reaches an End … and a Beginning

1983: Pioneer 10 becomes the first human-made object to pass outside Pluto’s orbit and leave the central solar system.

Pioneer 10 must be considered one of the most successful spacecraft of all time. Designed for deep-space exploration, which at the time of its launch in 1972 meant pretty much anything beyond the moon, Pioneer 10 achieved a number of firsts while sending back valuable data along the way. Among the milestones:

• Following liftoff, Pioneer 10 achieved a breakaway speed of 32,400 mph, making it the fastest human-made object to leave the Earth. It shot past the moon in a mere 11 hours and crossed Mars’ orbit in just 12 weeks. By the time it reached Jupiter on Dec. 3, 1973, Pioneer 10 was moving along at a crisp 82,000 mph.
• On July 12, 1972, Pioneer 10 became the first spacecraft to pass through the asteroid belt. NASA described this as a “spectacular achievement” and — considering that asteroids the size of Alaska hurtle through the belt at 45,000 mph — there’s no reason to dispute the claim.
• Upon reaching Jupiter, Pioneer 10 sent back the first direct observations and close-up images of the solar system’s largest planet. It was data from Pioneer 10 that confirmed that Jupiter is mostly a liquid planet.
• After clearing Pluto’s orbit (considered the boundary of the planetary solar system in the decades before astronomers decided Pluto isn’t really a planet), Pioneer 10 continued to send back valuable data regarding solar wind, until its scientific mission ended in 1997.

All attempts to contact Pioneer 10 were terminated following the spacecraft’s last transmission of telemetry data April 27, 2002. Nevertheless, NASA’s Deep Space Network received a final, faint signalJan. 22, 2003. It’s been silence ever since.

Although lost to contact forever, Pioneer 10 continues its endless journey through interstellar space. It’s headed in the general direction of Aldebaran, the brightest star in constellation Taurus, forming the bull’s eye. According to NASA, it will take about 2 million years for Pioneer 10 to reach Taurus.

So Pioneer 10’s mission, originally intended to go 21 months, lasted 25 years and change. As project manager Larry Lasher said, “I guess you could say we got our money’s worth.”

Source: NASA

Image: Since becoming the first human-made object to travel to Pluto, Pioneer 10’s signals have been lost. (Courtesy Don Davis)

This article first appeared on Wired.com June 13, 2008.