that maneuver frequently have a special problem in that their future position for conjunction avoidance analysis must include the effects of a planned maneuver. Unfortunately JSpOC currently can include this effect only by manually loading a predicted ephemeris file sent by a satellite owner who is aware of the planned delta-v. All this requires close interagency cooperation. There seems to be a pattern that organizations with a close relationship with the JSpOC for conjunction assessment are satisfied whereas those without such a relationship are not.

Finding: The community that is interested in conjunction assessments needs further improvements in the quality of the characterization of uncertainty (covariance) realism in the predicted ephemerides.

Anticipated Future Needs

The space catalog has been growing dramatically in recent years with the breakup of the Fengyun 1C satellite from the Chinese anti-satellite test and the collision of the Iridium and Cosmos satellites. These events have placed a greater emphasis on predicting satellite conjunctions and providing warning to satellite owner/operators of potential collisions. Conjunction assessments and launch screenings have greatly increased the workload at the JSpOC. The space catalog lost list (objects whose element set epoch age exceeds 30 days) is currently at an all-time high. The cataloging of satellite breakup pieces and the recovering of lost satellites from uncorrelated tracks are manually intensive and require the talents of subject-matter experts who are often in short supply.

The space catalog will grow even more dramatically with additions to the Space Surveillance Network of new and future sensors such as the space fence radar and the Space Surveillance Telescope, which because of their increased sensitivity will discover small debris objects in space that have never been tracked before.

In addition, because of changes in the U.S. National Space Policy there is an increased emphasis on sharing of space situational awareness data with mission partners and commercial and foreign entities. New standardized astrodynamics algorithms will be required for the exchange of space situational awareness data. Besides the traditional Space Surveillance Network sensors, nontraditional sensors (e.g., Missile Defense Agency sensors) may become additional contributors to the space situational awareness mission. Each of these changes will make the space situational awareness mission more complex and will require improved algorithms to fuse and exploit the information generated by this increase in diverse data types. Subsequent chapters of this report will describe some of the possibilities for modernization to deal with these changes.



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement