From: Centre for Research in Earth and Space Technology
Posted: Friday, November 12, 1999
Centre for Research in Earth and Space Technology Toronto, Ontario
office (416) 665-5464, cell (416) 707-9120,
Press Release - November 12, 1999
Elusive Meteor Storm Offers Last Glimpse
Toronto -- The debris of Comet Tempel-Tuttle, better known as the Leonid Meteor Storm, is once again on Earth's radar screen for the night of November 17 and likely for the last time until roughly the year 2032.
The mysterious debris field is of great concern to scientists and satellite owners. As Earth passes through the path of Tempel-Tuttle's highly elliptic orbit, satellites within Earth's gravitational field will face their greatest risk of physical damage since the huge Leonids storm of 1966.
The Centre for Research in Earth and Space Technology (CRESTech) is once again leading a global observation and risk-reduction program to try and build a comprehensive model of the Leonid meteor storm. Though the Leonids only appear every 32-33 years, they offer immense insight toward building forecasting technology that could help protect the world's satellite fleets from similar astral activity.
CRESTech's clients for the 1999 program include the Canadian Space Agency (CSA), the Department of National Defence (DND), NASA, the United States Air Force Space Command (USAF) and the European Space Agency (ESA).
Last year's program surprised many scientists when instead of seeing a massive quantity of "shooting stars," many viewers in the Far East were treated to a show of large fireballs, few in number but highly visible. As a result of travelling through a different "slice" of the meteor field, this year's event is anticipated to result in massive quantities of shooting stars, but few large fireballs.
Through the involvement of researchers at the University of Western Ontario and other Canadian and international institutions, the CRESTech-led team will set up electro-optical camps in Israel's Negev desert and the La Palma Observatory on the Canary Islands, considered to be the two best viewing points globally. Additional optical data will be collected by the USAF in Florida, Hawaii and the Kwajalain Atoll. Radar data will be collected in Northern Canada at a station in Alert, Nunavut.
A full backgrounder on the Leonids program is available at "www.crestech.ca/leonids" as are links to NASA and ESA descriptions of the event.
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CRESTech is made possible through the Ontario government's Centres of Excellence Program.
For more information, please contact:
(416) 665-5464, cell (416) 707-9120
Media Backgrounder - November 12, 1999
Statement of Problem
Many scientists believe that between 1998-2002 there may be a large, transitory increase in the meteoroid hazard in the near-Earth space environment resulting from the Leonid meteor shower. The Leonid stream, which emanates from the constellation of Leo and orbits around the Sun, has a 33-year travel cycle. It peaks over a three-to-five year time span matching the period during which the parent comet (Comet Tempel-Tuttle) travels closest to the Earth. Historically, there have been observations of over 40 visible meteors per second to ground observer during the climax of these storms. This peak period is normally preceded by a few years of build-up, during which an indication of potential activity can be recorded from the ground. This increase in activity is roughly 10,000 times the norm and results in an accumulation equal to that of several years regular activity in our skies.
There is a general consensus within the scientific community that some enhanced activity will be realized due to the next shower, however useful predictions are not possible due to limited historic data. During the last major meteor storm, in 1966, satellites were much smaller and less numerous than today. Today there are estimated to be between 600 and 750 operational satellites in Earth's orbit. While many space-faring nations, predominantly the United States, have devoted considerable resources to measuring and understanding "space weather" phenomena caused by solar activity and other aspects of the space environment, meteoroid activity has not figured prominently in this effort.
The hazards to spacecraft result not only from the large number of meteoroids, particularly those of smaller masses, but from the high speed of the Leonid meteoroids (72 kilometres per second). The effects of such impact may range from infrastructure damage to the more serious threat of electro-static discharge generated from such an impact. Such charges could interact directly with a spacecraft's electrical systems and essentially "short-circuit" the satellite. The latter effect has been proposed as the likely explanation for the loss of ESA's Olympus telecommunications platform in 1993. All satellites, both military and civilian, at all orbital altitudes are at risk from this natural threat.
Extensive work has been performed by the University of Western Ontario in London, Ontario, under the funding auspices of the Toronto-based Centre for Research in Earth and Space Technology (CRESTech), to model the physical processes resulting in the appearance of this storm. This unique model allows for predictive capabilities so long as appropriate observational data are available to constrain the initial conditions. However, observational data is not yet sufficient to provide accurate forecasts of the shower over the next five years. Observations made in 1997 and 1998 indicate that, and agree with, the recent discussions at an American Institute of Aeronautics and Astronautics/Aerospace Corporation Conference proposing that activity level may exceed as high as 1,000 naked-eye observable meteors per hour.
The International Program
In 1997, the primary participants in the project were NASA, the United States Air Force (USAF), the Canadian Space Agency (CSA), Canada's Department of National Defence (DND) and CRESTech. In 1998 the same partners were joined by the European Space Agency and Hughes Space Corporation. With the increasing awareness of the Leonid threat, the participants in the 1999 project are the USAF, NASA, CSA, DND, and the European Space Agency (ESA).
Organizations participating in the operational portion of CRESTech's program will receive real-time data on the storm's build-up rate, peak and general activity. It is expected that these data will be used by some satellite operators to take one of several courses of action in the event that peak activity reach dangerously high levels. Among those actions are: changing a spacecraft's attitude (i.e. pointing direction) to avoid being hit in crucial or delicate areas; powering down an endangered spacecraft so as to avoid a massive electrical discharge; or riding out the storm with enhanced ground-station teams in order to react quickly to storm- generated anomalies.
The 1999 Observation Campaign
Location: The two sites best suited for electro-optical observations are the Israeli desert and La Palma Observatory on the Canary Islands. Additional electro-optical data will be collected by the USAF at sites in Florida, Hawaii and the Kwajalain Atoll.
Instruments: The 1999 campaign will employ two methods of data collection: radar and Low-Light-Level Television (LLTV) observations. Both are capable of measuring the smallest meteoroids (which are the population relevant to the space hazard) and each can be used to establish their physical parameters. The Israeli site will host two LLTV sites (each with approximately five camera), and the La Palma site will host one radar site as well as one LLTV site (with two cameras). The radar data will be collected at Alert, Nunavut in Northern Canada.
Science Team: The CRESTech science team includes Dr. Jim Jones, Dr. Alan Webster, Dr. Kerry Ellis, Dr. Robert Hawkes, Ms. Margaret Campbell and Dr. Peter Brown, who acts as the project manager. This represents the largest group of meteor specialists in the world with a most varied list of strengths. Dr. Hawkes (Mount Allison University, Sackville, NB) is the world expert in application of video technology to meteor observations and heads the LLTV component of the program working along with Ms. Campbell (University of Western Ontario). Drs. Jones, Webster and Ellis (CRC Ottawa) are world leaders in meteor radar systems, observations and analysis. Dr. Brown (UWO) has studied and adapted models of the stream and liaise with the satellite community in an effort to understand satellite effects of the storm. No other single group has the equivalent breadth of scientific expertise in this field.
* European Space Agency's Leonids site
http://www.esoc.esa.de/pr/esoc.topics/1999.11/leonids/leonids.php3 * NASA's Leonids site
For more information on the CRESTech program, please contact:
office (416) 665-5464, cell (416) 707-9120,
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