Proposed microwave transponders for early lunar robotic landers

• Published in: Advances in space research Vol. 14; no. 6; pp. 233 - 242
• Main Author: Bender, Peter L.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.1994
• ISSN: 0273-1177; 1879-1948
• DOI: 10.1016/0273-1177(94)90033-7

The possibility of placing Ka-band microwave transponders on the Moon with early robotic landers is being explored. For measurements from a single observatory on Earth to transponders at two or more well-separated lunar sites, the atmospheric correction uncertainty for the range difference would be about 0.05 mm. With the carrier phase difference as the observable, the overall accuracy goal for the range difference is about 0.2 mm, except for a constant bias. The factor 100 accuracy improvement compared with current lunar laser range measurements would givemuch more definitive information on the existence and size of a fluid core, as well as highly accurate measurements of the lunar tidal distortion and possibly information on turbulent motions in the core. The estimated maximum power, average power, and mass for a transponder plus broad beam antenna are 10 W, 0.2 W, and 10 kg.