NASA scientists have recently contacted Pioneer 10 after nearly a year of radio silence. On March 2nd--the spacecraft's 30 year anniversary--NASA sent Pioneer a message bidding the spacecraft farewell. To their surprise 21 hours and 45 minutes later in came a faint reply.
For decades we have watched Pioneer 10's voyage. Now over 7.4 billion miles away, Pioneer has left a legacy of accomplishments. It was the first spacecraft to pass through the asteroid belt and obtain close up pictures of Jupiter, which until then had only been viewed through telescopes. It helped scientists understand Jupiter's intense radiation belts and magnetic fields.
In 1983 Pioneer 10 became the first man-made probe to leave our solar system when it passed beyond the orbit of distant Pluto. Since then, it has studied energy particles from the Sun and cosmic rays from deep space.
Pioneer 10 carries a famous gold plaque--an attempt by humans to communicate with other beings should the spacecraft be found by aliens during its journey through deep space.
The plaque displays a picture of two humans in front of Pioneer to show their relative sizes. The plaque also displays a hydrogen atom in transition from one energy state to another. There is a return address--a diagram of our solar system--so the creatures who find Pioneer will know from whence it came.
A diagram of 14 pulsars and their frequencies are included. Pulsars slow down over time. The change in the pulsars' frequencies will show how much time has passed since Pioneer left Earth.
A nuclear power source has enabled the spacecraft to keep running for all this time and hopefully many years to come. Pioneer is traveling at a constant speed of about 27,830 km per hour and is headed toward the red star Aldebaran, the right eye of Taurus, the bull. The spacecraft may reach Aldebaran in about two million years.
The spacecraft's mission officially ended March 31, 1997 at a distance of 6.28 billion miles from Earth, but NASA tells us they'll continue to track Pioneer as long as its signal holds out. "The fact that we can still stay connected with the spacecraft is fantastic!" exclaimed Pioneer project leader Dr. Larry Lasher. If the strength of the signal holds out we might be able to stay in contact with it another year.
Good luck, Pioneer 10. We've grown up with you, and now we'll continue to watch you go where no spacecraft has ventured before. We look forward to seeing you leap across the boundary of interstellar space, away from our familiar Sun. Your legacy of accomplishments and place in history will never be forgotten.