title: Dust observations at orbital altitudes surrounding Mars.
abstract: Dust is common close to the martian surface, but no known process can lift appreciable concentrations of particles to altitudes above ~150 kilometers. We present observations of dust at altitudes ranging from 150 to above 1000 kilometers by the Langmuir Probe and Wave instrument on the Mars Atmosphere and Volatile Evolution spacecraft. Based on its distribution, we interpret this dust to be interplanetary in origin. A comparison with laboratory measurements indicates that the dust grain size ranges from 1 to 12 micrometers, assuming a typical grain velocity of ~18 kilometers per second. These direct observations of dust entering the martian atmosphere improve our understanding of the sources, sinks, and transport of interplanetary dust throughout the inner solar system and the associated impacts on Mars's atmosphere.
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA. laila.andersson@lasp.colorado.edu.
authors.forename: L
authors.initials: L
authors.lastname: Andersson
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA.
authors.forename: T D
authors.initials: TD
authors.lastname: Weber
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA.
authors.forename: D
authors.initials: D
authors.lastname: Malaspina
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA.
authors.forename: F
authors.initials: F
authors.lastname: Crary
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Ergun
authors.affiliation: Space Science Laboratory, University of California-Berkeley, Berkeley, CA 94720, USA.
authors.forename: G T
authors.initials: GT
authors.lastname: Delory
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Fowler
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA.
authors.forename: M W
authors.initials: MW
authors.lastname: Morooka
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA.
authors.forename: T
authors.initials: T
authors.lastname: McEnulty
authors.affiliation: Swedish Institute of Space Physics, Uppsala, Sweden.
authors.forename: A I
authors.initials: AI
authors.lastname: Eriksson
authors.affiliation: Swedish Institute of Space Physics, Uppsala, Sweden.
authors.forename: D J
authors.initials: DJ
authors.lastname: Andrews
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA.
authors.forename: M
authors.initials: M
authors.lastname: Horanyi
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA.
authors.forename: A
authors.initials: A
authors.lastname: Collette
authors.affiliation: Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: R
authors.initials: R
authors.lastname: Yelle
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado-Boulder, Boulder, CO 80303, USA.
authors.forename: B M
authors.initials: BM
authors.lastname: Jakosky