P081-0002
The Future of Planetary Surface Gravimetry
Wednesday, 16 December 2020
Poster
Kevin W Lewis, Johns Hopkins University, Morton K. Blaustein Department of Earth & Planetary Sciences, Baltimore, MD, United States, Nicholas C Schmerr, University of Maryland College Park, College Park, MD, United States, Ashwin Seshia, University of Cambridge, Department of Engineering, Cambridge, United Kingdom, Paul B Niles, NASA Johnson Space Center, Houston, TX, United States, Ashwin R Vasavada, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, David T Blewett, JHU Applied Physics Lab, Laurel, MD, United States, Mark Southwick Robinson, Arizona State University, Tempe, AZ, United States and Jeremy Sotzen, Johns Hopkins University, Baltimore, MD, United States
Abstract:
Gravimetry has long been an established technique for mapping the shallow subsurface and deeper interior structure of the Earth. Gravity measurements are a standard analytical tool for both economic and scientific geophysical surveys. Likewise, gravity surveys have been conducted at many of the planetary bodies in our solar system, including the Moon and Mars. However, for bodies other than the Earth, surveys are almost entirely limited to data collected from orbit. Only two surveys have been collected from the surface of another planetary body: the Apollo 17 Traverse Gravimeter Experiment (Talwani, 1976) on the Moon, and a recent survey on Mars using the Curiosity rover's engineering accelerometers (Lewis, 2019). Because the downward continuation of gravity data collected at altitude amplifies high frequency noise, lower altitudes are necessary to resolve smaller-scale structures. For the Moon and Mars, current global gravity models approach the limit of what can be achieved from orbit, and higher-resolution gravity data will need to be collected from the surface.
Traditional spring-based gravimeters are both large and fragile, making them difficult to include on planetary spacecraft. However, the advent of Microelectromechanical Systems (MEMS) gravimeters (Middlemiss, 2016; Mustafazade, 2020) offers a new possibility for future landed or airborne missions. The Curiosity rover accelerometers are an example of MEMS technology being utilized for gravity measurements, although at lower sensitivity (10 mGal) than modern terrestrial gravimeters. We are currently working to mature newly developed dedicated MEMS gravimeters (Mustafazade, 2020) for future planetary application. This new generation of sensors have a sensitivity of <10 uGal, and could resolve cm-scale changes in elevation on the surface of the terrestrial planets.
We will discuss the results of the current gravity measurements on Mars obtained from the Curiosity rover along its traverse, and the implications for the geologic history of its field site at Gale crater. Future measurements as with the Perseverance rover at Mars or the proposed Intrepid rover at the Moon would enhance the science return from those missions, as subsurface structural information provided by gravity data is difficult to obtain through other analytical methods.
