The Spacewatch project at the University of Arizona is a pioneering planetary defense initiative dedicated to tracking near-Earth objects (NEOs) to prevent them from becoming “lost” in space. Founded in 1980 by Professor Tom Gehrels and Dr. Bob McMillan, the project revolutionized astronomy by pioneering the use of automated software to detect moving space rocks.
Today, as part of the “next generation” of asteroid tracking, Spacewatch has shifted its core strategy from broad sky surveys to targeted high-priority follow-up observations of the most hazardous objects. Core Mission & Strategy Shift
Targeting Virtual Impactors: Spacewatch focuses on “Virtual Impactors” (VIs)—asteroids with a small but non-zero mathematical probability of hitting Earth within the next 100 years.
Orbital Refinement: Instead of just discovering new rocks, the team tracks recently spotted, incredibly faint asteroids. Measuring their positions precisely reduces orbital uncertainty and clarifies whether they pose an actual threat.
Ground-to-Space Synergy: Spacewatch acts as the crucial ground-based tracking partner for massive next-generation space surveys, such as NASA’s upcoming NEO Surveyor Mission and the ground-based Legacy Survey of Space and Time (LSST). Technology & Operations
The Kitt Peak Observatories: Operations are based at the Kitt Peak National Observatory in Arizona, utilizing 1.8-meter and 0.9-meter telescopes.
The “Stacking” Method: Because the priority asteroids are incredibly small or distant, individual telescope exposures are often too faint to show them. The team takes multiple sequential images and “stacks” them digitally based on the predicted path of the asteroid. In the final image, the stars stretch into lines while the moving asteroid appears as a sharp, clear dot.
Faint Object Mastery: Spacewatch is highly efficient at tracking Potentially Hazardous Asteroids (PHAs) that are fainter than a visual magnitude of 22.5. Funding & Global Integration
The project is fully funded by a NASA grant under the NASA Planetary Defense Coordination Office (PDCO). All data collected by the Spacewatch team is instantly routed to the Minor Planet Center, which functions as the global clearinghouse for asteroid tracking data, helping scientists worldwide map the future layout of our solar system.
Are you interested in a specific part of asteroid tracking? I can provide more details if you let me know:
Are you interested in the upcoming NEO Surveyor space telescope? Next Asteroid Close Approaches – NASA JPL Watch
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