Updating the NASA debris engineering model: a review of source data and analytical techniques Original Research Article

Orbital debris engineering models present a comprehensive view of the space environment to spacecraft designers and owners/operators. NASA is revising its orbital debris engineering model, ORDEM96, to incorporate approximately four years of new observations of the low Earth orbit (LEO) environment and new analytical methodologies. Since its last revision, significant measurements of the LEO environment have been made using radar and optical sensors (e.g. the Haystack and Haystack Auxiliary Radars and the Liquid Mirror Telescope) and returned surfaces (the Space Shuttle, the Hubble Space Telescope solar arrays, and the European Retrievable Carrier). This paper reviews the data sources and outlines analytical techniques used to reduce data to engineering quantities such as flux and directionality. Also, this paper describes one of the new analytical techniques - a method of building statistical distributions of orbit families. We use a Maximum Likelihood Estimator to take a given set of data and estimate the orbit populations that created that particular data set. This method precludes the ability to say whether a particular detected object is in a particular orbit, but it gives an overall picture of the debris families in orbit within the limits of the sampling error.