title: Laser ranging retro-reflector: continuing measurements and expected results.
abstract: After successful acquisition in August of reflected ruby laser pulses from the Apollo 11 laser ranging retro-reflector (LRRR) with the telescopes at the Lick and McDonald observatories, repeated measurements of the round-trip travel time of light have been made from the McDonald Observatory in September with an equivalent range precision of +/-2.5 meters. These acquisition period observations demonstrated the performance of the LRRR through lunar night and during sunlit conditions on the moon. Instrumentation activated at the McDonald Observatory in October has yielded a precision of +/-0.3 meter, and improvement to +/-0.15 meter is expected shortly. Continued monitoring of the changes in the earth-moon distance as measured by the round-trip travel time of light from suitably distributed earth stations is expected to contribute to our knowledge of the earth-moon system.
authors.forename: C O
authors.initials: CO
authors.lastname: Alley
authors.forename: R F
authors.initials: RF
authors.lastname: Chang
authors.forename: D G
authors.initials: DG
authors.lastname: Currie
authors.forename: S K
authors.initials: SK
authors.lastname: Poultney
authors.forename: P L
authors.initials: PL
authors.lastname: Bender
authors.forename: R H
authors.initials: RH
authors.lastname: Dicke
authors.forename: D T
authors.initials: DT
authors.lastname: Wilkinson
authors.forename: J E
authors.initials: JE
authors.lastname: Faller
authors.forename: W M
authors.initials: WM
authors.lastname: Kaula
authors.forename: G J
authors.initials: GJ
authors.lastname: Macdonald
authors.forename: J D
authors.initials: JD
authors.lastname: Mulholland
authors.forename: H H
authors.initials: HH
authors.lastname: Plotkin
authors.forename: W
authors.initials: W
authors.lastname: Carrion
authors.forename: E J
authors.initials: EJ
authors.lastname: Wampler