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Pan-STARRS to Search for "Killer Asteroids"


Massive Terrestrial Strike. An artist's concept of a catastrophic asteroid impact with Earth. Life near the impact would be instantly wiped out from the effects of high temperatures and pressures. Injection of huge masses of dust (and gases) into the atmosphere would effectively block out sunlight for so long that most life could not be sustained ("nuclear winter"). Artist Don Davis for NASA. impact.arc.nasa.gov/gallery

IfA astronomers have been awarded a $3.4 million grant by the Air Force Research Laboratories to design a new observatory to survey the entire sky and detect very faint objects. A major goal of the project is to identify, long before impact, asteroids that might collide with Earth.

The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) is currently conceived of as an array of small telescopes, and sites on either the Big Island or on Maui are being considered. Planned to become operational in 2006, Pan-STARRS will be more powerful for survey work than all existing telescopes combined.

Commenting on the project, Dr. Kudritzki said, "I am pleased that the Institute will be able to play an important role in finding these hazardous asteroids that threaten humanity."

Exploiting recent advances in electronic detector technology, Pan-STARRS will have revolutionary optical sensors with billions of pixels, or picture elements. The IfA is collaborating with Lincoln Laboratory of the Massachusetts Institute of Technology (MIT) to develop the advanced detectors.

The telescopes will have a very large field of view, allowing them to image an area about 30 to 40 times that of the full moon in a single exposure. The system will rapidly survey large areas of the sky, making it uniquely powerful for detecting transient objects such as supernovae, and for detecting moving objects, such as asteroids.

Once operational, Pan-STARRS will generate huge quantities of data. To process these, the IfA astronomers have teamed up with the Maui High Performance Computer Center (MHPCC), and with Science Applications International Corporation (SAIC), a leader in the field of massive databases.

The huge database generated by Pan-STARRS will be made available over the Internet so that others may use it for education and research. Kudritzki commented that the Pan-STARRS database will be "a unique opportunity for education."

The currently favored design is an array of four relatively small telescopes. This would permit rapid construction, and would have a small environmental impact, because the system would be very compact. In fact, one possibility being explored is to house the system within the university's existing telescope building on Mauna Kea.

The IfA is working closely with the Office of Mauna Kea Management, and in accord with the design review process set out in the Mauna Kea Science Reserve Master Plan, to develop a design that minimizes environmental and cultural impacts.

The data from Pan-STARRS will be used to address many scientific questions, ranging from the origin of the solar system to the properties of the Universe on the largest scales. However, a major goal of the project is to inventory potentially dangerous asteroids.

While most asteroids reside in the main asteroid belt lying between Mars and Jupiter, some, known as near-Earth objects (NEOs), have orbits that pass inside that of Earth, and therefore present a collision hazard. It is now widely recognized that a collision with a large asteroid was responsible for the mass extinction of the dinosaurs 65 million years ago, and that more frequent collisions with smaller asteroids present a real hazard. Fatal asteroid collisions are rare, but when they happen they can be very destructive. In fact, experts have determined that, averaged over time, the risk of dying from an asteroid strike is approximately that of dying in a plane crash. A number of recent widely publicized close encounters with asteroids have highlighted the risk.

Congress has charged NASA with supporting searches for large asteroids that might collide with Earth. These surveys determine the orbits of the asteroids that they discover, and then project them forward to see if they will impact Earth. Pan-STARRS principal investigator Nick Kaiser comments that "current surveys have detected roughly half of the objects bigger than a mile in diameter. Impacts of this size cause global-scale catastrophes. Pan-STARRS will help complete this task and will extend the search to much smaller objects."

Early November saw a burst of activity associated with the start-up of the Pan-STARRS project. The IfA hosted several panels of outside experts for five full-day meetings during the week of November 11. The purpose of the meetings was to sharpen the data-processing and scientific goals of the program.

For more information about Pan-STARRS (formerly called the Panoramic Optical Imager Project), see www.ifa.hawaii.edu/pan-starrs/. For more information about the hazards of near-Earth objects, see the Web sites listed on the right.

Nick Kaiser, the principal investigator for Pan-STARRS and the associate director for national telescope projects at the Institute for Astronomy, shared his enthusiasm about Pan-STARRS after receiving funding from the Air Force Research Laboratories.