[IGSMAIL-1980] Leonid shower -- November 1998

[Jim]

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IGS Electronic Mail      Tue Aug 11  4:50:57 PDT 1998      Message Number 1980
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Author: Jim Ray
Subject: Leonid shower -- November 1998

This is an alert of possible satellite anomalies in mid-November due to the
intense Leonid meteor "storms" expected then.


____________________Forward Header_____________________
Subject:    R 051832Z-AUG-98 LEONID SHOWER NOVEMBER 1998//
Author: CINCLANTFLT NORFOLK VA//N633/N610//
Date:       8/10/98 8:26 PM

UNCLAS  //N02300//


SUBJ/LEONID SHOWER NOVEMBER 1998//
POC/GEORGE, S/CWO2-UHF OFFICER/-/COMM:540-653-6595/
/TEL:DSN:249-6595//

RMKS/1.  THIS MESSAGE IS TO HEIGHTEN YOUR AWARENESS AND DISCUSS
PREPARATIONS FOR THE NOVEMBER 1998 AND 1999 LEONID METEOR STORMS.

2.  EACH NOVEMBER, THE EARTH CROSSES THE PATH OF THE COMET
TEMPLE-TUTTLE.  AS THE EARTH PASSES THROUGH THE DEBRIS TRAIL FROM
THIS COMET, THE LEONID METEOR SHOWER OCCURS. TYPICALLY THIS RESULTS
IN ABOUT 15 METEORS PER HOUR ENTERING THE EARTHS ATMOSPHERE.  BUT,
ON CERTAIN OCCASIONS THE METEOR ACTIVITY CAN REACH "STORM" LEVELS,
WITH THOUSANDS OF METEORS OBSERVED PER HOUR.  THE COMET'S ORBITAL
PERIOD IS APPROXIMATELY 33 YEARS.  THIS YEAR, AND NEXT, WILL BE THE
MOST INTENSE METEOR STORMS OF THE 33 YEAR CYCLE.  THE PEAK PERIOD OF
THE METEOR ACTIVITY LASTS FOR A SPAN OF TWO TO SIX HOURS, AND CAN BE
FAIRLY ACCURATELY ESTIMATED.  THIS YEAR'S PEAK IS EXPECTED ON
NOVEMBER 17TH, APPROXIMATELY 1900 ZULU.  LITTLE IS KNOWN ABOUT THE
EFFECTS OF THIS INCREASED METEOR ACTIVITY ON SATELLITES.  THE LAST
STORM, IN 1966, WAS DURING A TIME WHEN THE NUMBER OF SATELLITES ON
ORBIT WAS NEGLIGABLE.  TODAY, THE NUMBER OF ACTIVE SATELLITES ON
ORBIT IS OVER 500.

3.  FROM THE PERIOD OF 171100Z-180100Z NOV 98 ALL USERS OF SATELLITE
ASSETS SHOULD MONITOR THEIR SYSTEMS VERY CAREFULLY.  THIS PERIOD IS
SIX HOURS PRIOR TO AND SIX HOURS AFTER THE EXPECTED HEIGHT OF THE
METEOR STORM.  ANY COMMUNICATIONS ANOMALIES OR OUTAGES SHOULD BE
ADDRESSED THROUGH NORMAL CHANNELS VIA IMMEDIATE MESSAGE TO THEIR
SERVICING SATELLITE ASSET MANAGEMENT CENTERS.

4.  NAVAL SPACE COMMAND IS CURRENTLY ACTIVE IN THE PLANNING FOR
LEONID METEOR STORM CONTINGENCIES.  CURRENT PLANS ARE TO ADD MANNING
AT THE SATELLITE OPERATIONS CENTERS AND REDUCE ROUTINE COMMANDING
DURING THE METEOR SHOWER.  THESE ACTIONS WILL ALLOW FOR ALL EFFORTS
TO BE DIRECTED TOWARD CORRECTING ANY SATELLITE ANOMALY SHOULD ONE
OCCUR.  FURTHER INFORMATION WILL BE PROVIDED AS APPROPRIATE.  ANY
QUESTIONS CONCERNING THE LEONID METEOR SHOWER CAN BE DIRECTED TO THE
POC ON THIS MESSAGE.

5.  RECOMMEND WIDEST DISTRIBUTION OF THIS MESSAGE TO SATELLITE USERS.



[Mailed From: Jim Ray (USNO 202-762-1444) <jimr at maia.usno.navy.mil>]