NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Flux of Millimetric Space DebrisIn 21.4 hr of zenith radar observations on 4 days at 8510 MHz, we found 831 particles with altitudes between 177 and 1662 km. From the duration of the echoes and the angular size (0.030 deg) of the antenna beam 157 particles were identified as passing through the side lobes and not through the main beam. Our analysis is based on the 674 particles that did not broaden the beam. On the assumptions that these particles went through the main beam, their radar cross sections vary between 0.02 and 260 sq mm , and their radial velocities vary between +/- 700 m/s. If they are conducting spheres, their diameters lie between 2 and 18 mm. If not, they must be larger. The flux of these particles, that is the number per sq km day, was determined in 100 km intervals. The maximum flux, 3.3 particles per sq km day, occurs at 950 km altitude. The small and large particles are not well mixed. The largest particles occur beyond 1000 km and middle-sized particles are missing below 300 km. If the earth's atmosphere caused the smallest particles to lose energy from initial orbits identical to those of the large particles, the orbits would have lower eccentricity at low altitudes. We find a larger eccentricity for the inner particles, and conclude that two or more populations are present.
Document ID
19990095971
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Goldstein, R. M.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Goldstein, S. J., Jr.
(Virginia Univ. Charlottesville, VA United States)
Date Acquired
August 19, 2013
Publication Date
September 1, 1995
Publication Information
Publication: Astronomical Journal
Publisher: American Astronomical Society
Volume: 110
Issue: 3
ISSN: 0004-6256
Subject Category
Astronautics (General)
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available