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Hamell, R.

Publications and source records attributed to Hamell, R..

6 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

Proceedings of the 2004 NASA/JPL Workshop on Physics for Planetary Exploration

The conference was held April 20-22, 2004, the NASA/JPL Workshop on Physics for Planetary Exploration focused on NASA's new concentration on sending crewed missions to the Moon by 2020 and then to Mars and beyond. However, our ground-based physics experiments are continuing to be funded, and it will be possible to compete for $80-90 million in new money from the NASA exploration programs. Papers presented at the workshop related how physics research can help NASA to prepare for and accomplish this grand scheme of exploration. From sensors for water on the Moon and Mars, to fundamental research on those bodies, and to aids for navigating precisely to landing sites on distant planets, diverse topics were addressed by the Workshop speakers.

Strayer, Donald M.↗
NASA NTRS2004

Small Mercury Ion Clock for On-board Spacecraft Navigation

I.Small Ion Clock Approach and Heritage: a) No lasers, uwave cavities, cryogenics, atomic beams, etc. b) Ions are electrically shuttled between separate optical and microwave traps. II. Each trap is optimized for its task: quadrupole for optical state selection; multi-pole for microwave clock. a) Very good stability shown in USNO. Timescale running "open loop." III. "Open loop" operation means no self-measurements of frequency offsets: (Zeeman, ion temperature,... etc.) a) Fewer parts and procedures, produces stable output continuously. IV. Ion clock is not so sensitive to temperature fluctuations a) Measured u:nshielded temperature coefficient of few 10(exp -15) per C. b) No bulky temperature isolation needed.

Prestage, John D.↗