A252-01
Janus: A NASA SIMPLEx mission to explore two NEO Binary Asteroids

Thursday, 17 December 2020: 05:30
Virtual
Daniel Jay Scheeres1, Jay McMahon2, Beau Bierhaus3, Joshua Wood4, Lance Benner5, Christine M Hartzell6, Paul Ottinger Hayne7, Robert Jedicke8, Lucille Le Corre9, Shantanu Naidu10, Petr Pravec11, Michael A Ravine12, Kya Sorli13 and Alex Meyer1, (1)University of Colorado Boulder, Ann and H.J. Smead Department of Aerospace Engineering Sciences, Boulder, CO, United States, (2)University of Colorado at Boulder, Ann and H.J. Smead Department of Aerospace Engineering Sciences, Boulder, CO, United States, (3)Lockheed Martin, Denver, CO, United States, (4)Lockheed Martin Space, Denver, United States, (5)JPL/Caltech, Pasadena, CA, United States, (6)University of Maryland College Park, College Park, MD, United States, (7)University of Colorado, Boulder, CO, United States, (8)University of Hawaii at Manoa, Honolulu, United States, (9)Planetary Science Institute, Tucson, AZ, United States, (10)University of California, LA, Los Angeles, CA, United States, (11)Fricˇova, Ondrˇejov, Czech Republic, (12)Malin Space Science Systems, San Diego, CA, United States, (13)University of Colorado at Boulder, Boulder, United States
Recorded Presentation
Abstract:
Janus is a NASA SIMPLEx mission currently in Phase B. The SIMPLEx program is designed around the idea of using secondary launch opportunities to explore interplanetary destinations. The Janus mission concept takes advantage of the NASA Psyche launch to send two spacecraft to fly by two Near Earth Objects binary asteroid systems, (175706) 1996 FG3 and (35107) 1991 VH, both of which have been observed repeatedly with photometry, spectrometry and radar (see Figure 1).

Janus sends light-weight, low-cost spacecraft built by Lockheed Martin to encounter these high-science value small body targets. The science instruments are a visible and IR imager, from Malin Space Science Systems. The spacecraft will perform a rigorous remote sensing campaign when the object is a point source, and when resolved. The spacecraft will track the binary asteroid systems through closest approach, allowing for a combination of absolute surface resolution, relative resolution across the target asteroids and phase angle coverage unparalleled in previous asteroid flyby missions.

Janus will combine flyby observations of the target binary asteroids with ground-based observations, enabling the high resolution imaging and thermal data to be placed into a global context and leveraging all available data to construct an accurate topographical and morphological model of these bodies. Based on these measurements, the formation and evolutionary implications for small rubble pile asteroids will be studied. Scientific questions related to each of the individual binary asteroids will also be investigated.

1996 FG3 has been documented to lie in a Binary YORP-Tide equilibrium, that has caused its dynamical evolution to stall. The observations of the secondary asteroid from the flyby will be used to construct a thermophysical model to estimate the Binary YORP coefficient of that body, which will provide insight on its internal tidal dissipation rate.

1991 VH has been documented to have an asynchronous secondary, which has a chaotic spin state which drives chaotic fluctuations in its orbit. Observations from the flyby will be used to model the secondary to test a range of hypothesis as to why it has yet to settle into a stable, synchronous rotation state.

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