EFFECT OF MULTI-WALL SYSTEM COMPOSITION ON SURVIVABILITY
FOR SPACECRAFT IMPACTED BY ORBITAL DEBRIS
JOEL E. WILLIAMSEN,
HILARY J. EVANS
and WILLIAM P. SCHONBERG
Denver Research Institute, University of Denver, Denver, CO 80208, USA;
Civil Engineering Department, University of Missouri-Rolla, Rolla, MO 65401, USA
(Tel.: (573) 341-4787; Fax: (573) 341-4729; E-mail: firstname.lastname@example.org)
(Received 27 January 1999; Accepted 8 June 1999)
Abstract. Long-duration spacecraft in low earth orbit such as the International Space Station (ISS) are highly
susceptible to high-speed impacts by pieces of debris from past earth-orbiting missions. Among the hazards
wall, crew hypoxia, and uncontrolled thrust due to air rushing out of the module wall hole. A Monte Carlo
simulation tool was used to determine the effect of spacecraft wall construction on the survivability of ISS
modules and crewfollowingan orbital debris penetration. The simulation results indicate that enhanced shield
wall designs (i.e., multi-wall systems with heavier inner bumpers) always lead to higher overall survivability
of the station and crew due to an overwhelming decrease in likelihood of module penetration. The results of
the simulations also indicate that changes in crew operations, equipment locations, and operation procedures
can signiﬁcantly reduce the likelihood of crew or station loss following an orbital debris penetration.
Keywords: hypervelocity impact, orbital debris, space station, survivability
Long-duration spacecraft in low earth orbit such as the International Space Station (ISS)
are highly susceptible to hypervelocity impacts by pieces of debris from past earth-orbiting
missions. With an increased likelihood of debris impact over longer mission time comes
a responsibility on the part of a spacecraft design engineer to quantify, and subsequently
reduce, the hazardous effects on a spacecraft and its crew should penetration occur. Among
the varioushazards that accompany the penetration of a pressurized manned spacecraft mod-
ule are unstable crack propagation in the module wall (i.e., the so-called “unzipping” of the
module) and depressurization-related phenomena, such as crew hypoxia and uncontrolled
thrust due to air rushing out of the module wall hole.
Figure 1 shows the normal impact of a multi-wall structure impacted by a spherical
projectile. In such a system, the outer and inner bumpers protect the pressure wall against
penetration by causing the disintegration of the impacting projectile and the creation of a
debris cloud which imparts a lower impulse per unit area to the pressure wall. The pressure
wall area over which the impulsive load is distributed is governed by the extent to which
the projectile and bumper materials fragment, melt, or vaporize, by the location of the inner
bumper within the dual-wall system, and the spacing between the bumpers and the pressure
Author for correspondence.
Space Debris 1, 37–43, 1999.
© 2000 Kluwer Academic Publishers. Printed in the Netherlands.