Galileo asteroid encounter navigationThe Galileo spacecraft will be targeted to encounter one or more asteroids during its cruise to Jupiter. Accurate navigation will maximize science return from these asteroid flyby opportunities. Navigation errors for these encounters are dominated by uncertainties in the asteroid ephemeris, which is obtained from fits to ground-based observations. As the spacecraft approaches, on-board optical navigation dramatically improves knowledge of the spacecraft-relative asteroid position normal to the line of sight, while correlations in the asteroid ephemeris provide moderate improvement along the approach direction. The remaining uncertainty in encounter time can be further reduced only by improving the ground-based asteroid ephemeris. Uncertainties perpendicular to the line of sight can be reduced by improving the timing of optical navigation images and their placement with respect to the star background. At the closest approach to the asteroid Gaspra, the one-sigma errors in knowledge of the spacecraft position are less than 10 km in position and 25 seconds in encounter time.
Document ID
19900059736
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Murrow, D. W. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Chodas, P. W. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Kallemeyn, P. H. (JPL Pasadena, CA, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1990
Subject Category
Space Communications, Spacecraft Communications, Command And Tracking