MODELING OF EJECTA PRODUCED UPON
and J.C. MANDEVILLE
CNES/CST, 18 Av. E. Belin, Toulouse, France (Fax: 05 61 28 16 17; E-mail: email@example.com);
ONERA/DESP, 2 Av. E. Belin, Toulouse, France (Fax: 05 62 25 25 69; E-mail: firstname.lastname@example.org)
(Received 16 April 1999; Accepted 3 October 1999)
Abstract. Each time a debris particle or a meteoroid strikes a satellite in orbit, a great amount of secondary
particles is ejected in the neighborhood of the impact site. This phenomenon is important in particular for
brittle materials, such as those used for solar arrays or thermal control paint. The secondary particles that do
not impactotherparts of the spacecraft are added to the primary debris population and hence increase the small
debris particle ﬂux. We describe an ejecta production model that gives the size and the velocity distribution
of ejected particles as a function of primary impact parameters. The model has been used to explain the
discrepancy between measurements and modeling of impact crater distribution on the solar arrays of the
Keywords: ejecta, hypervelocity impact, micrometeoroids, orbital debris, solar arrays
Photographic investigation of lunar and planetary surfaces provides a good example of the
importance of ejecta as an erosion and accretion process; many lunar basins and primary
craters are surrounded by ejecta blankets and associated secondary craters (McDonnell
et al., 1976).
Atasmallerscale,laboratoryexperimentsgive a good evidenceof material ejection during
hypervelocity impacts. In-ﬂight evidence has also been detected on satellites retrieved from
space. Figure 1 shows an example of a primary crater located on an experimental frame
of LDEF, with a bright zone showing erosion pattern produced by secondary craters on a
Every time a debris or a meteoroid hits a satellite in orbit, a great amount of secondary
particles, is ejected in the neighborhood of the parent body. This phenomenon is in particular
important for brittle materials, such as used for solar generators or thermal control paint. The
secondary particles that do not impact other parts of the structure are added to the primary
debris ﬂux and increase the collision risk. A satellite is therefore naturally polluting both
its own orbit and other orbits (Su and Kessler, 1985).
This paper describes a model of ejecta (Rival and Mandeville, 1998) developed primarily
for ESA, for implementation into the ESABASE space environment analysis tool.
1.1. Secondary cratering and ejecta
Ejecta, or secondary particles, are deﬁned as material ejected at a signiﬁcant velocity during
hypervelocity impact, called the primary impact. This matter is ejected under liquid, solid
Space Debris 1, 45–57, 1999.
© 2000 Kluwer Academic Publishers. Printed in the Netherlands.