STATUS AND PERSPECTIVES IN PROTECTIVE DESIGN
KLAUS THOMA, W. RIEDEL, F. SCH
AFER and S. HIERMAIER
ur Kurzzeitdynamik, Ernst-Mach-Institut (EMI),
Eckerstraße 4, 79104 Freiburg, Germany (E-mail: email@example.com)
(Received 20 December 2001; Accepted 15 February 2003)
Abstract. Starting with an introduction into the ﬁeld of hypervelocity impacts, an overview over current
research in the area of protection against space debris is given. Trends and strategies to further develop know-
how in protection technology are then discussed. One purpose is to demonstrate that improvements in shield
efﬁciency can be expected. To achieve this aim, a strategy is outlined which tries to avoid the adjustment of
numerical and material parameters by ﬁts to penetration experiments. Instead, it is suggested to determine
material parameters from carefully selected laboratory tests, covering a broad range of strains, strain rates
and stress states. Knowledge of the dynamic material behaviour can then be used for the development of new
shield concepts by means of numerical simulation.
Keywords: dynamic material testing, hypervelocity impact, material characterization, shielding of spacecraft
against space debris, simulation of perforation processes
1. Introduction: Space Debris and Hypervelocity Impacts
Space debris represents a serious threat for space missions. Awareness for space debris has
increased enormously since the ﬁrst pioneering works on its sources and distribution in orbit
were published, allowing to generate debris ﬂux models (Kessler et al., 1978, 1985). Impact
damages on retrieved spacecraft components due to micrometeoroids and space debris
have been analysed extensively. Prominent examples are components of the Hubble Space
Telescope and surfaces of the Space Shuttle (Hempsell, 1994; National Research Council,
1995; Bernhard et al., 1997; Christiansen, 1998b). When making projections for the future
development of the debris population (e.g., Bendisch and Wegener, 2001), independent of
the scenario used, the models predict an essential increase of the debris population (Figure 1).
Therefore, protection against the impact of space debris is a topic of continuously increasing
Despite this fact, research in the area of design of spacecraft protection has been rather
limited, in contrast, for example, to the tremendous efforts done in conventional protection of
earth-based vehicles (protection of automobiles and military vehicles, ships, and airplanes
against ballistic impacts). Constraints for the additional weight of protection are strong
in all mentioned applications, but there is a clear difference in impact velocities. Typical
impact velocities of space debris on spacecraft in low earth orbits range between 1000 and
15 000 m/s, well above the velocity range of about 800–3000 m/s considered in ballistic
protection or up to 8000 m/s considered for shaped charge encounter and missile defence.
Nevertheless, most of the methods applied in ballistic research can be extended to the ﬁeld
Space Debris 2, 201–224, 2000.
© 2004 Kluwer Academic Publishers. Printed in the Netherlands.