THE INVESTIGATION OF POSSIBLE APPROACHES OF CATALOGED SPACE
OBJECTS TO MANNED SPACECRAFT
and V.A. CHOBOTOV
Center for Program Studies, Moscow, Russia;
Center for Orbital and Reentry Debris Studies,
The Aerospace Corporation, 2350 E. El Segundo Blvd., CA 90245-4691, USA
(Received 18 January 2000; Accepted 25 August 2000)
Abstract. Initial orbital parameter errors are used to examine the miss distance between a spacecraft and an
ensemble of tracked objects by a Monte Carlo-type analysis. The radial separation between orbits is evaluated
and a keep-out zone is determined, which reduces the risk of collision to an acceptable level.
An operational prediction methodology is suggested based on a catalog database, which identiﬁes poten-
tially hazardous approaches and computes the probability of collision for selected spacecraft. An example
for the Mir Space Station is presented, which estimates the collision probability and the cross-sectional ﬂux
of cataloged objects for the time frame of interest. The results appear to be in good agreement with those of
other space debris models.
Keywords: collision probability, Mir Space Station, orbits, resident space objects, space debris, space debris
The problem of manned spacecraft safety is becoming more urgent because of the increasing
contamination of near Earth space. The development of the International Space Station
serves as another reason for the increased interest in this problem. Undoubtedly, from the
point of view of consequences (which can be catastrophic!), the most hazardous among all
possible collisions are the collisions with large cataloged space objects. A speciﬁc attribute
of such a collision is its predictability.
The Russian and the US space object catalogs form an informational database for the esti-
mation of the collision hazard. Two of the most important aspects which must be considered
• the prediction of all potentially hazardous close approaches,
• the hazard assessment for a speciﬁc close approach.
In Russia, the hazardous approach prediction methodology was developed at the end of
the 1960s. It was implemented in the Space Control Center. This methodology is used
to anticipate hazardous approaches to manned spacecraft and to conduct experiments of
Several studies, such as those in Chobotov (1982), Khutorovsky et al. (1995), and Foster
(1995), for example, discuss the problem of hazardous approach determination and assess-
ment. Nevertheless, the topic is not completely covered. In particular, the dependence of
Author for correspondence (Tel.: 310 336 4280; Fax: 310 3365827; E-mail: email@example.com).
Space Debris 1, 127–142, 2000.
© 2000 Kluwer Academic Publishers. Printed in the Netherlands.