Engineering topics

Mullins, N. E.

Publications and source records attributed to Mullins, N. E..

6 records

NASA NTRS1973

Mean elements of GEOS 1 and GEOS 2.

A combined analytical-numerical procedure for determining mean orbital elements is presented and applied to the orbits of GEOS 1 and GEOS 2. The precision of the mean semi-major axes of these orbits is a few tens of centimeters when optical flash data are used to determine 2 day orbital arcs. Four day Minitrack orbits give mean semi-major axes of a few meters precision. The mean orientation parameters determined from the optical data are obtained to a precision of about 0.1 sec.

Douglas, B. C.↗

NASA NTRS1972

GEODYN programmers guide, volume 2, part 1

A guide to the GEODYN Program is presented. The program estimates orbit and geodetic parameters. It possesses the capability to estimate that set of orbital elements, station positions, measurement biases, and a set of force model parameters such that the orbital tracking data from multiple arcs of multiple satellites best fit the entire set of estimated parameters. GEODYN consists of 113 different program segments, including the main program, subroutines, functions, and block data routines. All are in G or H level FORTRAN and are currently operational on GSFC's IBM 360/95 and IBM 360/91.

Mullins, N. E.↗

NASA NTRS1972

GEODYN programmer's guide, volume 2, part 2

A computer program for executive control routine for orbit integration of artificial satellites is presented. At the beginning of each arc, the program initiates required constants as well as the variational partials at epoch. If epoch needs to be reset to a previous time, the program negates the stepsize, and calls for integration backward to the desired time. After backward integration is completed, the program resets the stepsize to the proper positive quantity.

Mullins, N. E.↗

NASA NTRS1972

GEODYN operations description, volume 3

The operating and set-up procedures for the multi-satellite, multi-arc GEODYN- Orbit Determination program are described. All system output is analyzed. The GEODYN Program is the nucleus of the entire GEODYN system. It is a definitive orbit and geodetic parameter estimation program capable of simultaneously processing observations from multiple arcs of multiple satellites. GEODYN has two modes of operation: (1) the data reduction mode and (2) the orbit generation mode.

Martin, T. V.↗

NASA NTRS1972

GEODYN system support program, volume 4

The GEODYN Orbit Determination and Geodetic Parameter Estimation System consists of a set of computer programs designed to determine and analyze definitive satellite orbits and their associated geodetic and measurement parameters. This manual describes the Support Programs used by the GEODYN System. The mathematics and programming descriptions are detailed. The operational procedures of each program are presented. GEODYN ancillary analysis programs may be grouped into three different categories: (1) orbit comparison - DELTA (2) data analysis using reference orbits - GEORGE, and (3) pass geometry computations - GROUNDTRACK. All of the above three programs use one or more tapes written by the GEODYN program in either a data reduction or orbit generator run.

Mullins, N. E.↗

NASA NTRS1972

Mean elements of GEOS-1 and GEOS-2

A combined analytical-numerical procedure for determining precise mean orbital elements is presented and applied to the orbits of GEOS-1 and GEOS-2. The precision of the mean semi-major axes of these orbits is a few tens of centimeters when optical flash data is used to determine two-day orbital arcs. Four-day Minitrack orbits give mean semi-major axes of a few meters precision. The mean orientation parameters are obtained to a precision of about 0.1 sec (about 3m) or better from the optical orbits. This precision is adequate for determinations of tidal parameters, particularly in the case of GEOS-2, where the tidal perturbation of the inclination is 10 sec.

Douglas, B. C.↗