Kelso, T.S., David A. Vallado, Joseph Chan, and Bjorn Buckwalter, "Improved Conjunction Analysis via Collaborative Space Situational Awareness," presented at the 9th Advanced Maui Optical and Space Surveillance Technologies Conference, Maui, HI, 2008 September 19.
With recent events such as the Chinese ASAT test in 2007 and the USA 193 intercept in 2008, many satellite operators are becoming increasingly aware of the potential threat to their satellites as the result of orbital debris or even other satellites. However, to be successful at conjunction monitoring and collision avoidance requires accurate orbital information for as many space objects (payloads, dead satellites, rocket bodies, and debris) as possible.
Given the current capabilities of the US Space Surveillance Network (SSN), approximately 18,500 objects are now being tracked and orbital data (in the form of two-line element sets) is available to satellite operators for 11,750 of them (as of 2008 September 1). The capability to automatically process this orbital data to look for close conjunctions and provide that information to satellite operators via the Internet has been continuously available on CelesTrak, in the form of Satellite Orbital Conjunction Reports Assessing Threatening Encounters in Space (SOCRATES), since May 2004. Those reports are used by many operators as one way to keep apprised of these potential threats.
However, the two-line element sets (TLEs) are generated using non-cooperative tracking via the SSN�s network of radar and optical sensors. As a result, the relatively low accuracy of the data results in a large number of false alarms that satellite operators must routinely deal with. Yet, satellite operators typically perform orbit maintenance for their own satellites, using active ranging and GPS systems. These data are often an order of magnitude more accurate than those available using TLEs. When combined (in the form of ephemerides) with maneuver planning information, the ability to maintain predictive awareness increases significantly. And when satellite operators share this data, the improved space situational awareness, particularly in the crowded geosynchronous belt, can be dramatic and the number of false alarms can be reduced considerably.
Working with Intelsat, Inmarsat, EchoStar, SES, NOAA, Star One, and Telesat, CelesTrak now offers a new service—SOCRATES-GEO—which takes advantage of the availability of satellite operator-supplied orbital data through a shared data center, along with other improved sources of orbital information, to provide improved conjunction monitoring and automatic notification of potential threats based on user-defined criteria. This paper will discuss the SOCRATES-GEO process and demonstrate the potential improvements possible using satellite operator-supplied orbital data.
Conference Materials
Kelso, T.S., David A. Vallado, Joseph Chan, and Bjorn Buckwalter, "Improved Conjunction Analysis via Collaborative Space Situational Awareness," presented at the 3rd International Association for the Advancement of Space Safety Conference, Rome, Italy, 2008 October 22.
Satellite operators are becoming increasingly aware of the threat of on-orbit collisions—between satellites or with orbital debris. Successful conjunction monitoring and collision avoidance activities require accurate orbital information for as many space objects as possible. Current sources of orbital data are of low fidelity, as a result of how those data are generated, and are of limited value to conjunction analysis. However, satellite operators have much better data for their own satellites. When that data is shared among operators, overall space situational awareness can be significantly improved. This paper will demonstrate the potential improvements and discuss an operational implementation—SOCRATES-GEO—which uses operator data to improve conjunction monitoring.
Conference Materials
Kelso, T.S., David A. Vallado, Joseph Chan, and Bjorn Buckwalter, "Improved Conjunction Analysis via Collaborative Space Situational Awareness," presented at the Fifth European Conference on Space Debris, Darmstadt, Germany, 2009 April 2.
Satellite operators are becoming increasingly aware of the threat of on-orbit collisions—between satellites or with orbital debris. Successful conjunction monitoring and collision avoidance activities require accurate orbital information for as many space objects as possible. Current sources of orbital data are of low fidelity, as a result of how those data are generated, and are of limited value to conjunction analysis. However, satellite operators have much better data for their own satellites. When that data is shared among operators, overall space situational awareness can be significantly improved. This paper will demonstrate the potential improvements and discuss an operational implementation—SOCRATES-GEO—which uses operator data to improve conjunction monitoring.
Conference Materials