Citation
Abstract
A program of Apollo Lunar Surface Experiments Package (ALSEP)-Quasar Very Long Baseline Interferometry (VLBI) is being carried out at the Jet Propulsion Laboratory. These observations primarily employ a “4-antenna” technique, whereby simultaneous observations with two antennas at each end of an intercontinental baseline are used to derive the differential interferometric phase between a compact extragalactic radio source (usually a quasar) and a number of ALSEP transmitters on the lunar surface. A continuous ALSEP-quasar differential phase history over a few-hour period can lead to extremely high angular accuracy (< 10-* arcsecond) in measuring the lunar position against the quasar reference frame. Development of this application of the “4-antenna” technique has been underway at JPL for more than a year and is now producing high-quality data utilizing Deep Space Network (DSN) stations in Australia, Spain, and Goldstone, California, as well as the Spaceflight Tracking and Data Network (STDN) “Apollo” station at Goldstone. These high accuracy observations are of value to tie the lunar ephemeris to a nearly inertial extragalactic reference frame, to test gravitational theories, and to measure the Earth-moon tidal friction interaction.
Details
- Volume
- 42-33
- Published
- June 15, 1976
- Pages
- 37–54
- File Size
- 1.7 MB