Tidal Tomography to Probe the Moon’s Mantle Structure Using Lunar Surface Gravimetry Kieran A. Carroll1, Harriet Lau2, 1: Gedex Systems Inc.,
[email protected] 2: Department of Earth and Planetary Sciences, Harvard University,
[email protected] Lunar Tides Gravimetry of the Lunar Interior VEGA Instrument through the Moon's PulSE • Gedex has developed a low cost compact space gravimeter instrument , VEGA (Vector (GLIMPSE) Investigation Gravimeter/Accelerometer) Moon • Currently this is the only available gravimeter that is suitable for use in space Earth GLIMPSE Investigation: • Proposed under NASA’s Lunar Surface Instrument and Technology Payloads • ca. 1972 MIT developed a space gravimeter (LSITP) program. instrument for use on the Moon, for Apollo 17. That instrument is long-ago out of • To fly a VEGA instrument to the Moon on a commercial lunar lander, via NASA’s production and obsolete. Commercial Lunar Payload Services (CLPS) program. VEGA under test in thermal- GLIMPSE Objectives: VEGA Space Gravimeter Information vacuum chamber at Gedex • Prove the principle of measuring time-varying lunar surface gravity to probe the lunar • Measures absolute gravity vector, with no • Just as the Moon and the Sun exert tidal forces on the Earth, the Earth exerts tidal deep interior using the Tidal Tomography technique. bias forces on the Moon. • Determine constraints on parameters defining the Lunar mantle structure using time- • Accuracy on the Moon: • Tidal stresses in the Moon are proportional to the gravity gradient tensor field at the varying gravity measurements at a location on the surface of the Moon, over the • Magnitude: Effective noise of 8 micro- Moon’s centre, multiplies by the distance from the Moon’s centre.