Other
Scientific paper
Dec 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992acm..proc..407m&link_type=abstract
In Lunar and Planetary Inst., Asteroids, Comets, Meteors 1991 p 407-411 (SEE N93-19113 06-90)
Other
Cosmic Dust, Earth Orbital Environments, Long Duration Exposure Facility, Micrometeoroids, Particulates, Space Debris, Aerocapture, Asteroids, Fragmentation, Interplanetary Dust, Microparticles, Trajectories
Scientific paper
Definition of the Low Earth Orbit (LEO) particulate environment has been refined considerably with the analysis of data from NASA's Long Duration Exposure Facility (LDEF). Measurements of the impact rates from particulates ranging from sub-micron to millimetres in dimension and, especially, information on their directionality has permitted new scrunity of the sources of the particulates. Modelling of the dynamics of both bound (Earth orbital) and unbound (hyperbolic interplanetary) particulates intercepting LDEF's faces leads to the conclusion that the source is dominantly interplanetary for particle dimensions of greater than some 5 microns diameter; however the anisotropy below this dimension demands lower velocities and is compatible with an orbital component. Characteristics of the LDEF interplanetary component are compatible with familiar meteoroid sources and deep space measurements. Understanding of the orbital component which exceeds the interplanetary flux by a factor of 4 is less clear; although the very small particulates in orbit have been associated with space debris (Lawrance and Brownlee, 1986) this data conflicts with other measurements (McDonnell, Carey and Dixon, 1984) at the same epoch. By analysis of trajectories approaching the Earth and its atmosphere, we have shown that a significant contribution could be captured by aerocapture, i.e., atmospheric drag, from either asteroidal or cometary sources; such enhancement is unlikely however to provide the temporal and spatial fluctuations observed by the LDEF Interplanetary Dust Experiment (Mullholland et al. 1992). A further new mechanism is also examined, that of aerofragmentation capture, where an atmospheric grazing trajectory, which would not normally lead to capture, leads to fragmentation by thermal or mechanical shock; the microparticulates thus created can be injected in large numbers, but only into short-lifetime orbits. The concentration in one particular orbit plane, could explain the temporal fluctuations seen on LDEF; space debris could also explain the phenomenon.
McDonnell Anthony M. J.
Ratcliff P. R.
No associations
LandOfFree
The geocentric particulate distribution: Cometary, asteroidal, or space debris? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The geocentric particulate distribution: Cometary, asteroidal, or space debris?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The geocentric particulate distribution: Cometary, asteroidal, or space debris? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1112694