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Can neutral particles from comet Halley have reached the ice spacecraft?
Author(s) -
Daly P. W.
Publication year - 1987
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl014i006p00648
Subject(s) - halley's comet , comet , spacecraft , physics , astrobiology , relative velocity , astronomy , planet , comet nucleus , classical mechanics
To investigate the question of how neutral particles could travel from comet Halley to the ICE spacecraft, Kepler orbits are calculated that connect the positions of Halley and ICE, in space and time. From these orbits, the initial speed of the particle, relative to Halley, can be found as a function of departure time. It is found that there is a minimum relative speed of 7.5 km s −1 , for particles leaving the comet on February 6, 1986, three days before perihelion. Particles emitted before this date actually require a higher relative speed. Lower speeds of about 5 km s −1 are again possible for departure dates in November, 1985, when the molecular production rate is considerably reduced.