Editing Pioneer 10 (section)

===Deep space===
''Pioneer 10''  crossed the orbit of Saturn in 1976 and the orbit of Uranus in 1979.{{sfn|Fimmel|van_Allen|Burgess|1980|p=91}} On June 13, 1983, the craft crossed the orbit of [[Neptune]], and so became the first human-made object to leave the proximity of the major planets of the Solar System. The mission came to an official end on March 31, 1997, when it had reached a distance of {{Convert|67|AU|e9km e9mi|abbr=unit}} from the Sun, though the spacecraft was still able to transmit coherent data after this date.<ref name=prd65_8/>

After March 31, 1997, ''Pioneer 10''{{'}}s weak signal continued to be tracked by the Deep Space Network to aid the training of flight controllers in the process of acquiring deep-space radio signals. There was an [[NASA Institute for Advanced Concepts|Advanced Concepts]] study applying [[chaos theory]] to extract coherent data from the fading signal.<ref name=phillips2001/>

The last successful reception of [[telemetry]] was received from ''Pioneer 10'' on April 27, 2002; subsequent signals were barely strong enough to detect and provided no usable data. The final, very weak signal from ''Pioneer 10'' was received on January 23, 2003, when it was {{Convert|12|e9km|AU e9mi|abbr=unit}} from Earth.<ref>"This Month in History", ''Smithsonian'' magazine, June 2003.</ref> Further attempts to contact the spacecraft were unsuccessful. A final attempt was made on the evening of March 4, 2006, the last time the antenna would be correctly aligned with Earth. No response was received from ''Pioneer 10''.<ref name=lakdawalla2006/> NASA decided that the RTG units had probably fallen below the power threshold needed to operate the transmitter. Hence, no further attempts at contact were made.{{sfn|Angelo|2007|p=221}}