Daniel J. Scheeres
A5021928700- Astro and Planetary Science
- Planetary Science and Exploration
- Spacecraft Dynamics and Control
- Space Satellite Systems and Control
- Stellar, planetary, and galactic studies
- Geology and Paleoclimatology Research
- Spacecraft and Cryogenic Technologies
- High-pressure geophysics and materials
- Geomagnetism and Paleomagnetism Studies
- Isotope Analysis in Ecology
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Quantum chaos and dynamical systems
- Solar and Space Plasma Dynamics
- Target Tracking and Data Fusion in Sensor Networks
- Spacecraft Design and Technology
- Geophysics and Gravity Measurements
- Space Exploration and Technology
- Nuclear physics research studies
- Guidance and Control Systems
- Aerospace Engineering and Control Systems
- Scientific Research and Discoveries
- Inertial Sensor and Navigation
- earthquake and tectonic studies
- Geological and Geochemical Analysis
University of Colorado Boulder
2016-2025
University of Colorado System
2016-2025
Canada–France–Hawaii Telescope
2023
University of Hawaii System
2023
Laboratory for Atmospheric and Space Physics
2017-2020
The University of Melbourne
2018
NSF National Center for Atmospheric Research
2017
Charles University
2007-2015
Jet Propulsion Laboratory
1993-2015
Institute of Astronomy
2015
Abstract During its approach to asteroid (101955) Bennu, NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft surveyed Bennu’s immediate environment, photometric properties, rotation state. Discovery of a dusty natural satellite, or unexpected characteristics would have had consequences for the mission’s safety observation strategy. Here we show that observations during this period were highly sensitive satellites (sub-meter...
During the interval from September through early December 2005, Hayabusa spacecraft was in close proximity to near-Earth asteroid 25143 Itokawa, and a variety of data were taken on its shape, mass, surface topography as well mineralogic elemental abundances. The asteroid's orthogonal axes are 535, 294, 209 meters, mass is 3.51 x 10(10) kilograms, estimated bulk density 1.9 +/- 0.13 grams per cubic centimeter. correspondence between smooth areas (Muses Sea Sagamihara) gravitationally low...
The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present observations of Ryugu's shape, mass, and geomorphology. has an oblate "spinning top" with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates high-porosity (>50%) interior. Large surface boulders suggest rubble-pile structure. Surface slope analysis shows shape may have been produced from having once spun twice current rate. Coupled...
After global observations of asteroid 25143 Itokawa by the Hayabusa spacecraft, we selected smooth terrain Muses Sea for two touchdowns carried out on 19 and 25 November 2005 UTC first sample collection with an impact sampling mechanism. Here, report initial findings about geological features, surface condition, regolith grain size, compositional variation, constraints physical properties this site using both scientific housekeeping data during descent sequence touchdown. Close-up images...
High-resolution images of the surface asteroid Itokawa from Hayabusa mission reveal it to be covered with unconsolidated millimeter-sized and larger gravels. Locations morphologic characteristics this gravel indicate that has experienced considerable vibrations, which have triggered global-scale granular processes in its dry, vacuum, microgravity environment. These likely include convection, landslide-like migrations, particle sorting, resulting segregation fine gravels into areas potential...
Abstract We explore the hypothesis that, due to small van der Waals forces between constituent grains, rubble pile asteroids have a but nonzero cohesive strength. The nature of this model predicts that strength should be constant independent asteroid size, which creates scale dependence with relative increasing as size decreases. This counters classical theory behave scale‐independent cohesionless collections rocks. simple for is based on these weak forces, validate it through granular...
Abstract We review the results of an extensive campaign to determine physical, geological, and dynamical properties asteroid (101955) Bennu. This investigation provides information on orbit, shape, mass, rotation state, radar response, photometric, spectroscopic, thermal, regolith, environmental combine these data with cosmochemical models develop a hypothetical timeline for Bennu's formation evolution. infer that Bennu is ancient object has witnessed over 4.5 Gyr solar system history. Its...
Active asteroids are those that show evidence of ongoing mass loss. We report repeated instances particle ejection from the surface (101955) Bennu, demonstrating it is an active asteroid. The events were imaged by OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) spacecraft. For three largest observed events, we estimated ejected velocities sizes, event times, source regions, energies. also determined trajectories photometric properties...
Abstract Although no known asteroid poses a threat to Earth for at least the next century, catalogue of near-Earth asteroids is incomplete objects whose impacts would produce regional devastation 1,2 . Several approaches have been proposed potentially prevent an impact with by deflecting or disrupting 1–3 A test kinetic technology was identified as highest-priority space mission related mitigation 1 NASA’s Double Asteroid Redirection Test (DART) full-scale technology. The mission’s target...
Abstract The NASA Double Asteroid Redirection Test (DART) mission performed a kinetic impact on asteroid Dimorphos, the satellite of binary (65803) Didymos, at 23:14 UTC 26 September 2022 as planetary defence test 1 . DART was first hypervelocity experiment an size and velocity scales relevant to defence, intended validate means deflection. Here we report determination momentum transferred by impact. On basis change in orbit period 2 , find instantaneous reduction Dimorphos’s along-track...
Some active asteroids have been proposed to be formed as a result of impact events1. Because are generally discovered by chance only after their tails fully formed, the process how ejecta evolve into tail has, our knowledge, not directly observed. The Double Asteroid Redirection Test (DART) mission NASA2, in addition having successfully changed orbital period Dimorphos3, demonstrated activation an asteroid resulting from under precisely known conditions. Here we report observations DART with...
Abstract The Double Asteroid Redirection Test (DART) mission impacted Dimorphos, the satellite of binary near-Earth asteroid (65803) Didymos, on 2022 September 26 UTC. We estimate changes in orbital and physical properties system due to impact using ground-based photometric radar observations, as well DART camera observations. Under assumption that Didymos is an oblate spheroid, we its equatorial polar radii are 394 ± 11 m 290 16 m, respectively. instantaneously changed along-track velocity...
High-resolution radar images reveal near-Earth asteroid (66391) 1999 KW4 to be a binary system. The approximately 1.5-kilometer-diameter primary (Alpha) is an unconsolidated gravitational aggregate with spin period 2.8 hours, bulk density 2 grams per cubic centimeter, porosity 50%, and oblate shape dominated by equatorial ridge at the object's potential-energy minimum. 0.5-kilometer secondary (Beta) elongated probably denser than Alpha. Its average orbit about Alpha circular radius 2.5...
Abstract— Recent advances in the characterization of small body surfaces with stereophotoclinometry are discussed. The principal data output is an ensemble landmark maps (L‐maps), high‐resolution topography/albedo varying resolution that tile surface body. Because they can have a comparable to best images, and be located on global reference frame high accuracy, L‐maps provide significant improvement discriminatory power for studies bodies, ranging from regolith processes interior structure....