Pioneer Spacecraft First Into The Asteroid Belt Options

[Guest_PhilCo126_*]

Launch Pioneer 10 ( 02 March 1972 )
Pioneer 10 entered the Asteroidbelt in July 1972 and emerged in February 1973 ... passing safely as we know ... during 7 months ... Jupiter Flyby in November 1973.
So we had Jovian flyby 7 months after passing Asteroid belt!


Launch Pioneer 11 ( 05 April 1973 )
Pioneer 11 entered the Asteroidbelt in March 1974 and emerged in ??? ( September 1974 ) ... encountered Jupiter in December 1974.
Already 3 months after it cleared the Asteroid belt ?
( went on for flyby of Saturn in August 1979 )

Does someone have exact dates for both Pioneers' milestones ?


Best regards,
Philip

[edstrick]

http://cfa-www.harvard.edu/iau/lists/InnerPlot.html
http://cfa-www.harvard.edu/iau/lists/InnerPlot2.html
http://cfa-www.harvard.edu/iau/lists/OuterPlot.html

linked to from
http://pdssbn.astro.umd.edu/outreach/location.html
Show plots of more or less all natural objects in the solar system, color coded as to type.

The asteroid belt is clearly defined by an instantaneous snapshot as a torus with a rather well defined inner edge a little way outside Mars orbit and a more diffuse outer edge at about 2/3 the radius of Jupiter's orbit. The presence of additional scattered objects like near-earth asteroids <in red>, asteroids in (I think) 3/2 jupiter resonant orbits <3 lobes of green dots beyond the outer belt edge out to Jupiter's orbit> and Trojan asteroids <blue bananna shaped clusters of dots on jupiter's orbit -- jupiter is at about 8 o'clock>, does not change that there is a real belt that's well defined.

BUT: The objects in the belt are so small and the belt is so big, and vertically extended into a donut, not a flat disk, that anywhere at random in the belt, you'd usually only see a few not very bright stars that are asteroids in the distance.

Mariner 6 and 7 did fast flybys of Mars in 69, as the Atlas Centaur could launch considerably heavier spacecraft than the Mariners, and they got a modest gravity assist from the posigrade flyby of Mars. I don't have an orbital plot at hand, but they undoubtably went a short ways into the inner belt.

[tty]

http://cfa-www.harvard.edu/iau/lists/InnerPlot.html
http://cfa-www.harvard.edu/iau/lists/InnerPlot2.html
http://cfa-www.harvard.edu/iau/lists/OuterPlot.html

linked to from
http://pdssbn.astro.umd.edu/outreach/location.html
Show plots of more or less all natural objects in the solar system, color coded as to type.

I presume that the "black hole" in the Kuiper belt to the right of Pluto indicates the direction where the Milky Way makes observations difficult?

tty