FIGURE 2.3 Proposed new information dissemination model for two-line elements.
mission for a specific object by identifying fundamental changes in an object’s shape or mass due to deployments, or even enable estimates for the pointing of an object and its attendant imaging targets.
To enable such a richer catalog to become real, however, requires that the current limited catalog be enhanced to enable multiple object properties to be tied to each other across a distributed database. To be effective such a database must be flexible enough to enable inclusion of new properties without disrupting existing structures. Such relational databases have been developed to support the storage and retrieval of dynamical and contextual information for scientific missions, and have become a worldwide standard.127,128 In those applications, each object is provided with an identification number, which then can be used to uniquely associate many different aspects of that body, including ephemeris, attitude, and estimated constants. For complex bodies, these ID numbers can be further nested, allowing for a detailed and high-dimensional model to be tracked, thereby providing a framework for tracking satellite clusters and formations in the space situational awareness population. For active bodies, a history of events, maneuvers, and deployments can also be automatically accessed and evaluated.
Such existing products provide a direction for capturing the future potential of expanding object characterization beyond the currently limited approach. Because the storage of this information is not necessarily within a single file, but can be distributed across several files, it is also feasible for sensitive information about an object to be effectively segregated by omitting sensitive files from the distribution. Examples of such sensitive information may include attitude tracking, covariance information, and observed shape changes. The mere act of withholding that information would prevent it from being correlated with more common information such as ephemeris predictions.
Adoption of such a relational database approach could also help resolve the existing issues related to the dis-
127 C.H. Acton, Jr., Ancillary data services of NASA’s Navigation and Ancillary Information Facility, Planetary and Space Science 44(1):65-70, 1996.
128 C. Acton, N. Bachman, L. Elson, B. Semenov, F. Turner, and E. Wright, “Extending NASA’s SPICE ancillary information system to meet future mission needs,” SpaceOps 2002 Conference, Houston, Tex., October 9, 2002.