CCSDS 508.0-R-1, Conjunction Data Message (Red Book, Issue 1 ...

DRAFT CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGESReqt # Requirement Rationale TraceCDM-P10CDM-P11CDM-P12CDM-P13CDM-P14CDM-P15CDM-P16The CDM shall provide state vectorinformation for both objects involvedin the conjunction in a referenceframe that is clearly identified andunambiguous.The CDM shall provide for clearspecification of units of measure.The CDM shall provide a covariancematrix that includes at least 6x6position/velocity uncertaintyinformation.The CDM shall provide the mostrecently known operational status ofthe two objects.The CDM shall allow the possibilityto exchange information regardingconjunctions of objects orbiting anarbitrary body or point in space.The CDM shall provide data and/ormetadata that will allow the recipientto calculate the probability ofcollision if it is not provided by theCDM originator.The CDM must not require of thereceiving exchange partner theseparate application of, or modelingof, spacecraft dynamics orgravitational force models, orintegration or propagation.Clearly understanding the frame ofreference in which measurements areprovided is fundamental to theanalysis of most, if not all, physicalprocesses.Without clear specification of units ofmeasure, mistakes can be made thatinvolve the unit system in effect (e.g.,Metric or Imperial) and/or orders ofmagnitude (e.g., meters orkilometers).The determination of a satellite stateis subject to measurement andprocess uncertainties at all phases ofits development. Consideration ofthis uncertainty is a necessary part ofconjunction analysis and riskassessment. The covariance matrixcaptures the requisite uncertainty.Cited as required in ISO 16158(reference [D2]).This datum is required in order toassess the risk of collision andassess potential preventivemeasures. Cited as required in ISO16158 (reference [D2]).While Earth is the most likely objectabout which orbiting objects maycollide, there are other orbit centerswith more than one orbiting object(e.g., the Moon, Mars, Earth/Sun L1,Earth/Sun L2).Some CDM originators will not wantto explicitly provide a probability ofcollision, but their customers may beinterested in performing a calculationof their own based on data in theCDM.The situation in which a CDM isprovided may not allow time forchecking/confirming a predictedconjunction by a recipient. Someoperators may not be able to performthe required computations.3.4, Table 3-3,Table 3-4,4.3.10, 6.2.3,6.3.3Table 3-4Table 3-3Table 3-2Table 3-2,Table 3-3, Table3-4Table 3-2,Table 3-3, Table3-4CCSDS 508.0-R-1 Page B-3 March 2012