Engineering topics

Kirhofer, W. E.

Publications and source records attributed to Kirhofer, W. E..

10 records

NASA NTRS1983

Navigation of the Galileo mission

An overview of the navigation of the Galileo mission is given. Predicted navigation performance for the various mission phases is discussed with particular emphasis given to the tour phase. Orbit determination strategies and resulting accuracies are discussed for various data types. In particular, the results of combining a new Very Long Baseline Interferometry (VLBI) data type called Differential One-Way Range (DOR) with conventional radio and optical data types are presented. Maneuver strategy results include the effects of maneuver placement and various targeting methods on propellant consumption and delivery accuracy. Emphasis is placed on new results obtained using asymptote and split targeting.

Miller, L. J.↗

NASA NTRS1979

Orbit determination strategy and results for the Pioneer Venus Orbiter mission

This paper examines the orbit of the Pioneer Venus Orbiter as determined from earth based radio data. The basic orbit determination strategy together with its associated accuracy is presented, and the effect of the changing earth-Venus geometry on that accuracy is discussed. Orbital evolution from insertion to the present time is described and related to the primary forces acting on the spacecraft as well as to the weekly periapsis altitude trim maneuvers. Lastly, the technique used for orbit prediction in the presence of the uncertain Venus atmosphere and gravity environment is discussed.

Jacobson, R. A.↗

NASA NTRS1979

Venus - Density of upper atmosphere from measurements of drag on Pioneer orbiter

Measurements of the changes in orbital period of the Pioneer Venus orbiter are used to estimate the density of the upper atmosphere of Venus at altitudes in the range from 150 to 200 km. At 150 km, the dayside mean density is 1.4 times 10 to the -13th g/cc and the nightside mean density is 4 times 10 to the -14th g/cc. The oscillatory patterns of density variation are described. The data for densities between 150 and 200 km on the dayside are sketchy but the data imply a scale height between 15 and 20 km.

Shapiro, I. I.↗

NASA NTRS1966

Ranger VII photographic parameters

Tables of computer generated photographic parameters necessary for detailed interpretation of Ranger VII television camera pictures - trajectory and time-to-impact data

RANGER VII LUNAR PROBE↗

NASA NTRS1966