Remember the first pioneer crafts launched in 1972 sent to collect data from Jovian space? Pioneer 10 and its twin, Pioneer 11, have done their work. During these past decades they blazed a trail to Jupiter and Saturn, being the first craft to enter the asteroid belt. They were also the first man-made craft designed to leave our solar system. After leaving Jovian space, they traveled onward well beyond the orbit of Pluto, and eventually fell silent. Pioneer 11 faded out in 1995 and Pioneer 10 sent us its last clear signal December of 2003.
NASA's intersteller space mission collected much data, but during the years tracking specialists noticed something odd: neither craft was exactly where it was supposed to be.
After crossing billions of miles in space, they were instead thousands of miles closer to the Sun than expected - not a great deal but significant enough to have people wondering if it was a sign that we needed some unknown "refinement" to the theory of gravity, our bedrock of modern physics.
The latest findings and conclusions by JPL tells us no exotic explanation is in order. Some of this slowing down was due to uneven emmission of heat radiating from the spacecraft. So it made sense the craft would not be "on track" all this time.
Pioneer 10 may sound familiar as it was the craft that carries our "introduction" to any life-forms in the outer regions of space it might encounter on its trek through the galaxy.
This is the gold-amodized plaque still aboard Pioneer 10 designed in part by the late Dr. Carl Sagan, depicting a human man and woman, a map of Earth's solar system, and other symbols which would help intelligent beings interpret the message and understand its creators, earthlings. You might also remember the recording of "Hello" in every known language in the world. Imagine where this craft might be now ...
We did a great job in constructing the pioneers, which outlasted even the programming language and data formats of their launch time. Just to give you an idea of how well-made these craft were, Pioneer 10 was expected to last only 21 months! And here it went on for 30 years! I like to think that someday when the craft are found, by whatever life form, mankind will have survived as a species and be able to welcome the visitors who will certainly want to visit us.
Thank you, noble pioneers, for the invaluable knowledge you've given humankind about Jupiter and Saturn, their atmosphere, and that section of our system we once thought so mysterious. A job well done.