Engineering topics

Standish, E. Myles, Jr.

Publications and source records attributed to Standish, E. Myles, Jr..

3 records

NASA NTRS1989

A determination of the masses of Ceres, Pallas, and Vesta from their perturbations upon the orbit of Mars

Measurements of Mars-orbit perturbations have been conducted in order to estimate the masses of the Ceres, Pallas, and Vesta asteroids. A full, least-squares adjustment of all ephemeris parameters, including the relevant asteroid masses, is compiled on the basis of observational data encompassing the highly accurate Viking Lander ranging data. The mass for Ceres, of 5.0 + or - 0.2 x 10 to the -10th solar masses, that for Pallas, of 1.4 + or - 0.2 x 10 to the -10th solar masses, and that for Vesta, of 1.5 + or - 0.3 x 10 to the -10th solar masses, respectively represent 15, 30, and 9 percent increases over Schubart's (1970, 1974, 1975) previous determinations.

Standish, E. Myles, Jr.↗

NASA NTRS1986

Numerical planetary and lunar ephemerides - Present status, precision and accuracies

Features of the emphemeris creation process are described with attention given to the equations of motion, the numerical integration, and the least-squares fitting process. Observational data are presented and ephemeride accuracies are estimated. It is believed that radio measurements, VLBI, occultations, and the Space Telescope and Hipparcos will improve ephemerides in the near future. Limitations to accuracy are considered as well as relativity features. The export procedure, by which an outside user may obtain and use the JPL ephemerides, is discussed.

Standish, E. Myles, Jr.↗

NASA NTRS1986

Dynamical evidence for Planet X

The dynamical evidence for a planet beyond the orbit of Neptune is reviewed. Three years of radio tracking data from Pioneer 10 can be fit to the noise level with no evidence for unmodelled acceleration at a level higher than 5 x 10 to the -14th km/sq s. The evidence does not place severe limits on the Planet X model, but does place a firm limit of five earth masses on a hypothetical comet belt just beyond the orbit of Neptune.

Anderson, John D.↗