Reports On How Satellites Weathered 1998 Leonid Shower
Due at Manhattan Beach Conference

EL SEGUNDO, Calif. (5/10/99) -- Satellite owners and operators will be reporting on how their spacecraft weathered the 1998 Leonid meteoroid shower when they meet May 11-13 in Manhattan Beach, California. They also will be gathering information to help them make preparations for this year's Leonid event.

No major spacecraft problems related to the Nov. 1998 celestial shower were immediately reported. But more detailed reports are to be presented at the meeting, according to William H. Ailor, Ph.D., director of the Center for Orbital and Reentry Debris Studies at The Aerospace Corporation, which is cosponsoring the meeting with the American Institute of Aeronautics and Astronautics (AIAA).

First Global Effort

The Leonid showers have spawned the first global effort to protect satellites from the space environment. The first Leonids conference held in April 1998 helped establish "baseline" procedures to protect satellites from meteoroid showers, solar flares and other threats.

Several satellites have been significantly damaged and even rendered inoperative by meteoroids in the past. In 1993 the European Space Agency's Olympus satellite was hit by a Perseids meteoroid and lost attitude control. In 1991 the sun filter on Japan's Solar A satellite was punctured, ending its mission. Space station Mir and the Hubble Space Telescope were also hit during the 1993 shower.

More Intense Storm Possible in 1999

Based on 1998 measurements and findings by scientists, some new predictions call for the Nov. 1999 Leonid event to be nearly ten times more intense than the 1998 shower. The findings also raise the possibility of significant Leonid events in 2000 and 2001.

Ailor said the 1999 "Leonid Meteoroid Storm and Satellite Threat Conference" will address all issues associated with meteoroids and the threats they pose to government and commercial satellites. Such areas as hypervelocity impact phenomenology, orbital dynamics, system response, and possible actions spacecraft owners and operators might take to minimize potential damage will be discussed by speakers and examined in papers.

Solar Maximum

Also included on the conference agenda is a session on the solar maximum scheduled to occur around 2000.

Possible Damage

If a spacecraft is struck, it can incur damage of many types. Solar panels and optical surfaces can be pitted; plasma jets from the impact site can cause electrostatic discharge-especially if the spacecraft carries a differential surface voltage; and electromagnetic pulses which might cause internal electronic failures and other problems can be formed. Catastrophic puncture and shock wave damage can also occur if the meteoroids are large enough, though they rarely are. Most are smaller than 0.1 millimeters in diameter, Ailor said.

The Leonids appear with intensity every 33 years or so when the comet Tempel-Tuttle passes near Earth. The showers occur between Nov. 15 and 21 with peak activity on the night of Nov. 17-18.

Then and Now

The last major Leonids storm occurred in 1966 at a time when fewer than 100 satellites were in orbit. Now more than 650 operational spacecraft are in orbit. These satellites form the infrastructure for worldwide communications and navigation, as well as Earth and weather monitoring capabilities.

Aerospace astrophysicist David K. Lynch, Ph.D., will serve as technical chair of the conference while Ailor is overall coordinator. The conference will be held at the Manhattan Beach Marriott at 1400 Parkview Avenue, near the intersection of Parkway/Nash and Rosecrans Avenue, just east of Sepulveda Boulevard.

Members of the organizing committee include Edward C. "Pete" Aldridge, Jr., president and CEO, The Aerospace Corporation; Lt. Gen. Eugene L. Tattini, commander, USAF Space and Missile Systems Center; Timothy W. Hannemann, executive vice president and general manager, TRW Space & Electronics Group; Gen. Richard B. Myers, commander in chief, North American Aerospace Defense Command; Gary K. Davis, director, Office of Satellite Operations, National Oceanic and Atmospheric Administration; Peter B. Teets, president, Lockheed Martin Corp.; Col. Simon P. Worden, deputy director, USAF Headquarters; James W. Evatt, executive vice president, The Boeing Company; and other leaders in the space community.