Boulder, Colorado, January 19, 2000 — Scientists at Southwest Research Institute (SwRI), in collaboration
with the NASA Dryden Flight Research Center in California, have successfully completed a proof-of-concept
program that places astronomers in the backseats of high-performance jet aircraft.

The program recently culminated with SwRI scientists using the
Institute-developed Southwest Ultraviolet Imaging System-Airborne (SWUIS-A) imager aboard a NASA F-18
to observe an asteroid occulting a star. “This observation will reveal the size of the asteroid 308 Polyxo,
which, like most asteroids, is too small for even the Hubble Space Telescope to resolve,” says Principal
Investigator Dr. S. Alan Stern, director of the SwRI Department of Space Studies in Boulder.

Dr. Daniel D. Durda, the SWUIS flight astronomer for the asteroid occultation mission, adds, “Our
observation with SWUIS-A, obtained from above the clouds that obscured the sky over Dryden during the
event, will be combined with three ground-based observations from other locations to deduce the asteroid’s

For decades, airborne astronomy and geophysical observations have proven useful adjuncts to
ground-based and space-based instrumentation, particularly for optical and infrared studies. Compared to
ground-based instruments, airborne research platforms offer superior atmospheric transmission and the
mobility to reach remote or otherwise unreachable locations, such as over oceans. Airborne platforms also
virtually guarantee good weather for observing the sky, and are far less expensive to operate than

A key advantage of small, high-performance platforms like F-18s over larger, more conventional airborne
platforms is the cost savings they generate. For example, an F-18 is about 10 times less expensive to
operate per hour than the KC-135/Boeing 707s and Boeing 747s typically used. Other advantages include
worldwide basing and faster reaction times to transient astronomical events.

Although these small aircraft cannot carry as large a payload or as sophisticated telescopes as larger
airborne observatories, the SwRI/NASA demonstration program enabled astronomers to fly along with their
instruments, providing a space shuttle-like “payload specialist” capability. Flight training for the astronomers
was funded largely through the SwRI internal research program.

To date, 14 SwRI/NASA airborne astronomy missions have been flown using the sensitive, but rugged,
SWUIS-A imager. These missions included high-altitude flights in NASA WB-57s to observe comet Hale-Bopp
and in NASA F-18s to perfect techniques for observing asteroid and planetary occultations over oceans.

Future SWUIS-A missions aboard high-altitude aircraft, such as two-seater U-2s flying at up to 75,000 feet,
will capitalize on the ability of the instrument to look near (and soon, even at) the sun to search for
Vulcanoids — an assumed population of small asteroids circling the sun inside Mercury’s orbit — and to
observe breakup mechanics in sun-grazing comets. SWUIS-A may also be used to detect and track space
debris that might pose a hazard to satellites, the space shuttle, and the International Space Station. The
application of SWUIS-A to study a variety of terrestrial aeronomical phenomena, including lightning and
sprites, aurora, and ozone studies, and future studies of meteoroid showers, missile tests, and other
phenomena of interest is also envisioned.

For more information about SwRI’s innovative airborne astronomy, contact Maria I. Martinez,
Communications Department, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas,
78228-0510, Phone (210) 522-3305, Fax (210) 522-3547.


For more information on Southwest Research Institute’s airborne astronomy capabilities, visit


* Closeup of the SWUIS-A system integrated into the NASA-F18B cockpit:

* Principal Investigator Alan Stern (rear cockpit) and NASA pilot Gordon Fullerton conducting the initial
flight test of the SWUIS-A system in an F-18:

* Other images to support this story are available at: