Citation
Abstract
In December 1984, the Soviet Union launched two identical Vega spacecraft with the dual objectives of exploring Venus and continuing to rendezvous with the comet Halley. The two Vega spacecraft encountered Venus in mid-June 1985 and successfully deployed entry probes and wind-measuring balloons into the Venus atmosphere. An objective of the Venus Balloon experiment was to measure the Venus winds using differential VLBI from the balloon and the flyby bus. NASA’s Deep Space 64-meter subnet was part of a 20-station worldwide network organized to collect data from the Vega probes and balloons. A critical element of this experiment was an accurate determination of the Venus relative flyby orbits of the Vega spacecraft during the 46-hour balloon lifetime. Venus Slyby solutions were independently determined by the Soviets using two-way range and doppler from Soviet stations and by JPL using one-way doppler and VLBI data collected from the DSN. This article compares the Vega flyby solutions determined by the Soviets using a sparse two-way tracking strategy with JPL solutions using the DSN VLBI data to complement the Soviet data and with solutions using only the one-way data collected by the DSN.
Details
- Volume
- 42-93
- Published
- May 15, 1988
- Pages
- 271–279
- File Size
- 505.6 KB