TY - JOUR
T1 - Seismology on small planetary bodies by orbital laser Doppler vibrometry
AU - Sava, Paul
AU - Asphaug, Erik
N1 - Funding Information:
This work was supported by the NASA Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) program ( NNH16ZDA001N ). The Center for Wave Phenomena at Colorado School of Mines provided logistic and computational support. The reproducible numeric examples used the Madagascar open-source software package ( Fomel et al., 2013 ), freely available from www.ahay.org .
Funding Information:
This work was supported by the NASA Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) program (NNH16ZDA001N). The Center for Wave Phenomena at Colorado School of Mines provided logistic and computational support. The reproducible numeric examples used the Madagascar open-source software package (Fomel et al. 2013), freely available from www.ahay.org.
Publisher Copyright:
© 2019 COSPAR
PY - 2019/7/15
Y1 - 2019/7/15
N2 - The interior structure of small planetary bodies holds clues about their origin and evolution, from which we can derive an understanding of the solar system's formation. High resolution geophysical imaging of small bodies can use either radar waves for dielectric properties, or seismic waves for elastic properties. Radar investigation is efficiently done from orbiters, but conventional seismic investigation requires landed instruments (seismometers, geophones) mechanically coupled to the body. We propose an alternative form of seismic investigation for small bodies using Laser Doppler Vibrometers (LDV). LDVs can sense motion at a distance, without contact with the ground, using coherent laser beams reflected off the body. LDVs can be mounted on orbiters, transforming seismology into a remote sensing investigation, comparable to making visual, thermal or electromagnetic observations from space. Orbital seismometers are advantageous over landed seismometers because they do not require expensive and complex landing operations, do not require mechanical coupling with the ground, are mobile and can provide global coverage, operate from stable and robust orbital platforms that can be made absolutely quiet from vibrations, and do not have sensitive mechanical components. Dense global coverage enables wavefield imaging of small body interiors using high resolution terrestrial exploration seismology techniques. Migration identifies and positions the interior reflectors by time reversal. Tomography constrains the elastic properties in-between the interfaces. These techniques benefit from dense data acquired by LDV systems at the surface, and from knowledge of small body shapes. In both cases, a complex body shape, such as a comet or asteroid, contributes to increased wave-path diversity in its interior, and leads to high (sub-wavelength) imaging resolution.
AB - The interior structure of small planetary bodies holds clues about their origin and evolution, from which we can derive an understanding of the solar system's formation. High resolution geophysical imaging of small bodies can use either radar waves for dielectric properties, or seismic waves for elastic properties. Radar investigation is efficiently done from orbiters, but conventional seismic investigation requires landed instruments (seismometers, geophones) mechanically coupled to the body. We propose an alternative form of seismic investigation for small bodies using Laser Doppler Vibrometers (LDV). LDVs can sense motion at a distance, without contact with the ground, using coherent laser beams reflected off the body. LDVs can be mounted on orbiters, transforming seismology into a remote sensing investigation, comparable to making visual, thermal or electromagnetic observations from space. Orbital seismometers are advantageous over landed seismometers because they do not require expensive and complex landing operations, do not require mechanical coupling with the ground, are mobile and can provide global coverage, operate from stable and robust orbital platforms that can be made absolutely quiet from vibrations, and do not have sensitive mechanical components. Dense global coverage enables wavefield imaging of small body interiors using high resolution terrestrial exploration seismology techniques. Migration identifies and positions the interior reflectors by time reversal. Tomography constrains the elastic properties in-between the interfaces. These techniques benefit from dense data acquired by LDV systems at the surface, and from knowledge of small body shapes. In both cases, a complex body shape, such as a comet or asteroid, contributes to increased wave-path diversity in its interior, and leads to high (sub-wavelength) imaging resolution.
KW - Asteroid
KW - Comet
KW - Imaging
KW - Laser
KW - Seismic
KW - Tomography
KW - Vibrometer
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U2 - 10.1016/j.asr.2019.04.017
DO - 10.1016/j.asr.2019.04.017
M3 - Article
AN - SCOPUS:85065259106
SN - 0273-1177
VL - 64
SP - 527
EP - 544
JO - Advances in Space Research
JF - Advances in Space Research
IS - 2
ER -