Asteroid Bennu

Asteroid Bennu
NASA/Goddard/University of Arizona · Public domain · source
Name	Bennu
Designation	101955 Bennu
Discovered	1999-09-11
Discoverer	Lincoln Near-Earth Asteroid Research
Aphelion	1.355 AU
Perihelion	0.896 AU
Semimajor	1.126 AU
Eccentricity	0.203
Period	1.19 yr
Inclination	6.034°
Mean diameter	~492 m
Mass	~7.8×10^10 kg
Spectral type	B-type (carbonaceous)

Asteroid Bennu Bennu is a near-Earth asteroid and potentially hazardous asteroid studied extensively by planetary scientists, mission engineers, and international observatories. It is the target of NASA's OSIRIS‑REx sample-return mission and has been central to research by institutions in the United States, Canada, Japan, and Europe. Observations from ground-based surveys and space telescopes refined its orbit, physical properties, and potential impact probabilities.

Discovery and Naming

Bennu was discovered by the Lincoln Near-Earth Asteroid Research program using the Lincoln Laboratory Experimental Test System, associated with Massachusetts Institute of Technology and operated from Socorro, New Mexico. The provisional designation tied to surveys by the Spacewatch project and follow-up by observatories such as Palomar Observatory, Kitt Peak National Observatory, and the Mauna Kea Observatories contributed to orbit determination. The permanent number 101955 was assigned by the Minor Planet Center under the International Astronomical Union. The name was proposed in a public naming contest coordinated by NASA and selected with involvement from University of Arizona researchers, with cultural input referencing the Egyptian Book of the Dead deity linked to renewal.

Orbit and Physical Characteristics

Bennu follows an Earth-crossing orbit in the Apollo group, with orbital elements refined by radar observations from the Arecibo Observatory and the Goldstone Deep Space Communications Complex. Dynamical studies by researchers at the Jet Propulsion Laboratory and the Planetary Science Institute use data from NEOWISE, Hubble Space Telescope, and the Very Large Telescope to model non-gravitational perturbations such as the Yarkovsky effect. Long-term integrations consider resonances with Jupiter, perturbations from Mars, and close approaches to Earth and Venus. Thermal inertia and bulk density estimates derive from infrared spectroscopy by Spitzer Space Telescope and radio science during spacecraft flybys. Bennu's rotation state, obliquity, and period were characterized through photometry from the University of Hawaii telescopes and coordinated campaigns involving the Cerro Tololo Inter-American Observatory.

Surface Composition and Geology

Spectral classification as a B-type body arises from comparisons with meteorite classes curated by the Smithsonian Institution National Museum of Natural History and meteoritic collections studied at the Natural History Museum, London and Vernadsky National Museum. Laboratory analog experiments at California Institute of Technology, Massachusetts Institute of Technology, and Brown University linked Bennu spectra to hydrated carbonaceous chondrites such as CI and CM types. Geological mapping by mission teams invoked geomorphology frameworks from the Lunar and Planetary Institute and used imaging standards from the International Astronomical Union. Surface features include boulders, regolith ponds, and interaction zones interpreted using theories from researchers at the Max Planck Institute for Solar System Research and the University of Western Ontario. Impact gardening, thermal fracturing, and cohesion models were developed in collaboration with scientists at NASA Ames Research Center and Johns Hopkins University Applied Physics Laboratory.

Exploration and OSIRIS‑REx Mission

The OSIRIS‑REx mission, managed by NASA and led by investigators at the University of Arizona, used the Atlas V launch vehicle provided by United Launch Alliance and navigated using the Deep Space Network. The spacecraft carried instruments built by teams at the Canadian Space Agency, Instituto Nacional de Técnica Aeroespacial, University of Colorado Boulder, and the University of California, Los Angeles. Instrument suites included imaging systems analogous to those developed by the Lockheed Martin Space Systems Company, spectrometers based on designs from NASA Goddard Space Flight Center, and sampling mechanisms inspired by prototypes tested at Sandia National Laboratories. The mission performed characterization campaigns coordinated with observatories such as Arecibo Observatory (radar), Green Bank Observatory, and the European Southern Observatory. Recovery and curation of returned samples involved the Johnson Space Center curation facility and international partnerships with museums and laboratories including the Field Museum of Natural History.

Impact Risk and Hazard Assessment

Impact probability assessments for Bennu were published by analysts at the Jet Propulsion Laboratory, the Near Earth Object Program Office, and the Minor Planet Center, incorporating non-gravitational forces modeled by teams at the Planetary Science Institute and the University of Pisa. Risk matrices referenced historical impact events like the Chicxulub impact, crater records from the Barringer Crater, and probabilistic frameworks used in United Nations Office for Outer Space Affairs guidance. Planetary defense exercises involved agencies such as NASA’s Planetary Defense Coordination Office, the European Space Agency, and research centers including the International Asteroid Warning Network and the Association of Space Explorers. Mitigation concepts studied by the Johns Hopkins APL, Los Alamos National Laboratory, and Sandia National Laboratories evaluated kinetic impactor, gravity tractor, and nuclear deflection scenarios in response to modeled Torino and Palermo Scale outcomes.

Scientific Findings and Sample Analysis

Remote-sensing and returned-sample analyses integrated expertise from the Carnegie Institution for Science, University of Tokyo, Swiss Federal Institute of Technology Zurich, and the University of Paris. Findings include evidence for hydrated minerals, organic macromolecules, and isotopic ratios informing models from the Cosmic Dust Laboratory and cosmochemistry groups at the Max Planck Institute for Chemistry. Geochronology used techniques developed at the California Institute of Technology and University of California, Berkeley to date alteration processes; organic chemistry studies involved protocols from the Jet Propulsion Laboratory and the Scripps Institution of Oceanography. Comparative planetology placed Bennu in context with meteorite falls curated by the Natural History Museum, Los Angeles County, small bodies explored by missions like Hayabusa, Hayabusa2, and Dawn, and sample-return archives maintained by the Smithsonian Institution. Ongoing multidisciplinary analyses continue at laboratories across the United States, Canada, Japan, France, Germany, and Australia to refine models of Solar System formation and volatile delivery to Earth.

Category:Near-Earth objects