Engineering topics
Publications and source records attributed to Zielenbach, J. W..
Two programs aid in trajectory analysis. DPTRAJ, ODP and their supporting utility programs capable of handling massive amounts of data and performing numerical calculations required for solving navigation problems associated with planetary fly-by and lander missions. Used extensively in support of Voyager.
A new navigational method combining electronic measurement procedures and celestial mechanics makes it possible to conduct a space probe very close to a desired point in the neighborhood of a remote planet. Approaches for the determination of the position of the space probe in space are discussed, giving attention to the effects of errors in the employed data. The application of the navigational methods in a number of space missions is also considered.
This document describes in general terms the spacecraft navigation process at JPL and the institutional elements involved in this effort. It cutlines the major computer and software systems used and indicates the basic functions of each of these components. It provides a thumbnail sketch of the OD portion of the navigation process by presenting the fundementals of OD as performed at JPL. In discussing the more recent history of the ODP at JPL including its use in research and flight operations, it covers the implementation of the system on JPL's General Purpose Computing Facility (GPCF) computers, it maintenance, daily operation and continuing development.
The extended process of providing station location estimates for use in orbit determination at launch and during the course of the mission, is outlined. Station location sets provided for Mariner Mars 1971 navigation support are given. Data cover set construction, basis for construction, and a comparison of estimated sets with final sets.
The effects of charged particle and tropospheric calibrations on the orbit determination (OD) process are analyzed. The calibration process consisted of correcting the Doppler observables for the media effects. Calibrated and uncalibrated Doppler data sets were used to obtain OD results for past missions as well as Mariner Mars 1971. Comparisons of these Doppler reductions show the significance of the calibrations. For the MM'71 mission, the media calibrations proved themselves effective in diminishing the overall B-plane error and reducing the Doppler residual signatures.
A final, comprehensive description of the navigation of Mariner 9-the first U.S. spacecraft to orbit another planet is provided. The Mariner 9 navigation function included not only precision flight path control but also pointing of the spacecraft's scientific instruments mounted on a two degree of freedom scan platform. To the extent appropriate, each section describes the perflight analyses on which the operational strategies and performance predictions were based. Inflight results are then discussed and compared with the preflight predictions. Postflight analyses, which were primarily concerned with developing a thorough understanding of unexpected in-flight results, are also presented.
The logistical aspects of orbit determination (OD) in the interplanetary phase of the Mariner Mars 1971 mission are described and the working arrangements for the OD personnel, both within the Navigation Team and with outside groups are given. Various types of data used in the OD process are presented along with sources of the data. Functional descriptions of the individual elements of the OD software and brief sketches of their modes of operation are provided.
Mariner 9 Mars 71 mission orbit determination, trajectory and maneuver strategy for near earth, cruise, planetary approach and satellite phases, using in-flight tracking data
Definitive orbit obtained for /48/ Doris based on mass of Jupiter
Mass of Jupiter system from motion of Doris, using variational equations for initial rectangular coordinates and velocities with respect to mass of Jupiter