Voyager 2, launched 20 Aug. 1977, had its closest approach with Jupiter
on 9 July 1979, with Saturn on 25 Aug. 1981, with Uranus on 24 Jan.
1986, and with Neptune on 25 Aug. 1989. Voyager 1, launched 5 Sep. 1977,
had its closest approach with Jupiter on 5 March 1979, and with Saturn
on 12 Nov. 1980.
Voyager 1 crossed the termination shock of the solar wind
on 16 Dec. 2004 at 94.0 AU. Voyager 2 crossed the termination shock several
times during 29-31 Aug. 2007 at 83.65 AU. Both spacecraft are now exploring
the shocked solar wind in the inner heliosheath. They are heading toward the
heliopause, the boundary that separates plasma of solar origin from the
interstellar medium.
By July 2008 Voyagers 1 and 2 will be at respective helioradii 107 AU
and 86 AU, heliographic latitudes N34 deg. and S28 deg., and will
be separated in longitude by 43 deg. Their rectilinear separation
will be about 118 AU. Each Voyager spacecraft carries a nearly identical
set of instruments that continue to monitor plasma, field, and energetic
particle activity in the outer heliosphere.
The LECP (Low Energy Charged
Particle) instruments on Voyagers 1 and 2 measure the
differential in energy fluxes and angular distributions of ions >30
keV and electrons >20 keV, and the differential in energy
ion composition >200 keV/nuc. Data acquired by these two
instruments during the past 31 years represent two-point measurements of
energetic particle variations over separations of about 20 AU in
radius and 62 deg. in latitude. During the next several years the
LECP instruments will continue to play vital roles in elucidating
the basic physics of energetic charged particle distributions in the
distant heliosphere, at the heliosphere's termination shock, in the
heliosheath plasma, and beyond.
For further information on the LECP instruments contact:
Dr. S. M. Krimigis (e-mail:
tom.krimigis@jhuapl.edu)
Dr. B. H. Mauk (e-mail:
barry.mauk@jhuapl.edu)
Dr. R. B. Decker (e-mail:
robert.decker@jhuapl.edu)
Dr. R. L. McNutt (e-mail:
ralph.mcnutt@jhuapl.edu)
All at:
The Johns Hopkins University,
Applied Physics Laboratory
11100 Johns Hopkins Road,
Laurel, Maryland 20723-6099, U.S.A.
