Second Sum Matrices For Acceleration Partials

SECTION fAWBER

NOTE: THIS FORMAT APPLIES TO ALL RECORDS EXCEPT THE FIRST AND THE SECOND. THE BLOCK SIZE FOR A FILE WITH NO PART1ALS IS 1092. THE BLOCK SIZE OF A FILE WITH PARTIALS IS 6880. A DATA RECORD WHEN ND PARTIALS ARE PRESENT IS 420 BYTES LONG; THIS RECORD CONSISTS OF BYTE LOCATIONS 1-416 AND 6657-6880.

NOTE: THIS FORMAT APPLIES TO ALL RECORDS EXCEPT THE FIRST AND THE SECOND. THE BLOCK SIZE FOR A FILE WITH NO PART1ALS IS 1092. THE BLOCK SIZE OF A FILE WITH PARTIALS IS 6880. A DATA RECORD WHEN ND PARTIALS ARE PRESENT IS 420 BYTES LONG; THIS RECORD CONSISTS OF BYTE LOCATIONS 1-416 AND 6657-6880.

Orbit Generators. Orbit generators may be classified as those which use Kepler's equation to determine position and velocity, and those which integrate the equations of motion directly using models of the forces. Only the former are discussed here and only elliptical orbits are considered. Recall from Chapter 3 that Kepler's equation relates, for an eliptic orbit, the mean anomaly,* M, at some time, t, to the eccentric anomaly, E, at the same time by

where e is the eccentricity. If t0 is the epoch time of the elements, then the mean anomaly at time t is found from the mean anomaly at epoch by

where n=2sr/period is the mean motion. The utility routine ORBGEN (Section 203) solves Kepler's equation numerically to find E at any time before or after the epoch using an iterative solution to Eq. (5-30) (obtained using Newton's method). Successive estimates of E are given by l-.cos^.,) (5"32)

* Angles are expressed in radians throughout this section.

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