ANALYSIS OF THE MICROMETEOROID AND DEBRIS HAZARD POSED
TO AN ORBITING PARABOLIC MIRROR
and A.B. JENKIN
Consultant, Center for Orbital Reentry and Debris Studies;
Senior Engineering Specialist, Astrodynamics
Department, The Aerospace Corporation, 2350 E-El Segundo Blvd., El Segundo, CA 90245-4691, USA
(Tel.: (310)336-4280; Fax: (310)336-5827; E-mail: firstname.lastname@example.org)
(Received 8 December 1999; Accepted 30 November 2001)
Abstract. Many concepts of future space systems involve the use of parabolic mirrors for optical applications.
The need for a highly reﬂective ﬁnish means that performance of such systems will be particularly vulnerable
to space debris and micrometeoroids. A case study was performed to examine the micrometeoroid and debris
hazard posed to an orbiting parabolic mirror. The mirror considered was nominally Earth-pointed in a circular
orbit with two candidate altitudes in low Earth orbit (LEO), well within the region inhabited by man-made
debris. The timeframes of interest for the two missions were 2002–2004 and 2005–2015. Microgram and
larger particles were considered.
To perform this study, it was necessary to determine the debris and meteoroid ﬂux across the parabolic
surface. To assess sensitivity of results to uncertainity in available data, two approaches were taken. The
ﬁrst approach was an analytical procedure based on use of long duration exposure facility (LDEF) data and
published theoretical results. The second approach used two readily available computer models: the ESA
MASTER model and NASA’s ORDEM96. In addition, an in-house implementation of the Gr
model was used. While multiple results were available for the total ﬂux and ﬂux distributed over azimuth, only
the MASTER model was available for generating the desired elevation data to obtain the ﬂux distribution over
the parabolic mirror. In an attempt to bound the uncertainty in the knowledge of the elevation distribution, the
results from both the MASTER and ORDEM96 models were processed together to form a separate, hybrid
prediction. In addition, results were used in the preliminary design of a protective skirt.
This case study elucidated the practical obstacles and considerations in performing a sufﬁciently accurate
debris and meteoroid analysis using data and tools that are readily available to the broad space sector. The
resulting procedures are useful in the assessment of the risk posed to optics by the meteoroid and debris
environment and in the design of protection.
Keywords: long duration exposure facility, low Earth orbit, MASTER, micrometeoroids, models,
ORDEM96, parabolic mirror, space debris ﬂux
A study was performed to examine the micrometeoroid and debris hazard to a spacecraft
carrying an orbiting parabolic optical reﬂector. The need for a highly reﬂective ﬁnish means
that such systems could be particularly vulnerable to the abundant small particulate pop-
ulation of space debris and micrometeoroids. The spacecraft and mirror considered were
nominally Earth-pointed in a circular orbit. The spacecraft conﬁguration is illustrated in
Figure 1. The focal length to diameter ratio, i.e., the F -number, was assumed to be 1.0. Two
candidate missions were considered. The ﬁrst mission occurs at an altitude of 500 km during
the timeframe 2002–2004. The second mission occurs at an altitude of 1500 km during the
timeframe 2005–2015. Both missions are well within the region inhabited by man-made
Space Debris 2, 9–40, 2002.
© 2002 Kluwer Academic Publishers. Printed in the Netherlands.