The Pioneers 10 and 11 spacecraft were launched on 2 March 1972 and 5 April 1973 and are now 53 and 35 AU from the sun. Pioneer 10 is now the most distant man-made object in our solar system and the in situ measurements of the gas and dust surrounding the sun have been obtained for almost two solar sunspot cycles. Plasma analyzer measurements out to 50 AU show that the mean velocity is about 430 km/sec, the mean density decreases as R exp -2, and that the terminal shock has not been encountered. The magnetic field is drawn out to form Archimedean spirals in the ecliptic place and dipolelike asymmetry in the polar directions as predicted by the Parker model. Galactic cosmic ray measurements of the intensity and radial gradient indicate a 'modulation boundary' between 70 to 100 AU from the sun. All measurements to date indicate that both spacecraft are within the heliosphere and proceeding toward the outer boundary where the modulating effect of solar activity on cosmic ray intensity ceases.


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    Title :

    Future operations of Pioneer 10 and 11


    Contributors:
    Dyal, P. (author)

    Published in:

    Publication date :

    1993-06-01



    Type of media :

    Miscellaneous


    Type of material :

    No indication


    Language :

    English


    Keywords :


    Future operations of Pioneer 10 and 11

    Dyal, P. | Elsevier | 1993


    Future Operations of Pioneer 10 and 11

    Dyal, P. | Online Contents | 1993




    Planetary operations for the pioneer venus orbiter mission

    Jackson, R.W. / Dyer, J.W. / Fimmel, R.O. | Tema Archive | 1988