The key element of NASA’s Planetary Defense effort is the Near-Earth Object (NEO) Observations Program, which is composed of projects to find, track, and characterize NEOs.
Objective
The current congressionally directed objective of the NEO Observations Program is to find, track, and characterize at least 90 percent of the predicted number of NEOs that are 140 meters and larger in size–larger than a small football stadium–and to characterize a subset representative of the entire population. Objects of this size and larger pose a risk to Earth of greatest concern due to the level of devastation an impact would cause, and should continue to be the focus of global search efforts. While no known asteroid larger than 140 meters in size has a significant chance to hit Earth for the next 100 years, less than half of the estimated 25,000 NEOs that are 140 meters and larger in size have been found to date.
Projects
The NEO Observations Program sponsors projects that make use of telescopes around the world to search for NEOs, track them across the sky to determine their orbits, and gain information on their sizes, shapes, and composition.
NASA Observatories
The NEOWISE Project repurposes the Wide-field Infrared Survey Explorer space telescope, designed as an all-sky survey telescope for astrophysics science, to continue to survey for NEOs and other small bodies using the remaining infrared channels on the telescope. Its most significant contribution determining NEO sizes with a precision not possible using optical measurements.
The Infrared Telescope Facility (IRTF) is located at the 13,800-foot summit of Maunakea on the Big Island of Hawaii. IRTF is used to study physical characteristics of NEOs and provide rapid response to newly discovered close-approach NEOs. In addition to characterizing NEOs, IRTF is used to study bodies throughout the Solar System and for astrophysics investigations outside the Solar System, all through open, peer-reviewed, competed observing time allocation. IRTF is supported through a management and science operations contract with the University of Hawaii.
NEO Orbit Determination, Prediction, and Archive
The Minor Planet Center (MPC) is the internationally agreed-to public archive of small-body orbit data submitted by observers from around the world. The MPC notifies observers worldwide about NEO discoveries so that timely follow-up observations can be collected for identification, and orbit computation. The MPC is sanctioned by the International Astronomical Union and functions as a subnode of NASA’s Planetary Data System Small Bodies Node.
The Center for Near-Earth Object Studies (CNEOS) computes high-precision orbit paths for NEOs from positions reported to the Minor Planet Center. CNEOS computes orbits for new asteroid discoveries and performs long-term analyses of possible future positions of hazardous asteroids relative to Earth to determine and warn of any impact hazard. CNEOS computes impact time and location in the event of a predicted impact. The Jet Propulsion Laboratory hosts CNEOS for the NEO Observations Program, and its website makes all orbit computation public.
NEO Detection and Tracking Survey Projects
Wide-field telescopes are used to image large parts of the sky to search for objects moving against the background of stars (watch NASA Planetary Defense: The Asteroid Hunters) and submit the positions to the Minor Planet Center.
Major NEO survey projects in the NEO Observations Program include:
- University of Arizona’s Catalina Sky Survey
- University of Hawaii’s Panoramic Survey Telescope and Rapid Response System (Pan-STARRS)
- University of Hawaii’s Asteroid Terrestrial-Impact Last Alert System (ATLAS)
- MIT Lincoln Laboratory’s Lincoln Near-Earth Asteroid Research (LINEAR)
NEO Follow-up and Characterization Projects
When an NEO is discovered by a survey, additional telescopes are used to “follow-up” those discoveries (watch NASA Planetary Defense: Backyard Asteroid Observer) and add position measurements to the Minor Planet Center, which the Center for Near-Earth Object Studies (CNEOS) uses to compute a precise orbit and predict the NEO’s trajectory well into the future. Telescopes are also used to study characteristics of NEOs such as physical composition, rotation, shape, and size.
Major NEO follow-up and characterization projects in the NEO Observations Program include:
- University of Arizona’s Spacewatch
- Astronomical Research Institute
- Las Cumbres Observatory
- New Mexico Tech’s Magdalena Ridge Observatory
- Lowell Observatory’s The Mission Accessible Near-Earth Objects Survey (MANOS)
Planetary Radar Projects
Ground-based planetary radar involves bouncing radar signals off of NEOs to precisely track and determine orbits and determine shapes physical characteristics when they approach within millions of miles of Earth.
Major radar projects in the NEO Observations Program include:
Meteors, Meteorite Collection/Analysis
The NEO Observations Program supports government agencies and institutions to detect and report meteors and fireballs, as well as search for meteorites on the ground.
Major projects include:
Mitigation Research Projects
The NEO Observations Program supports theoretical and laboratory studies of asteroid and meteorite properties to investigation impact risk and mitigation techniques.
Major projects include:
- NASA Ames Asteroid Threat Assessment Project (ATAP)
ATAP neoproperties site
Citizen Science
The International Astronomical Search Collaboration gives citizen scientists in schools the opportunity to learn about NEOs and NEO survey and search survey data for potential discoveries.