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(meteorobs) Excerpts from "CCNet 59/2001 - 24 April 2001"
------- Forwarded Message
From: Peiser Benny <B.J.Peiser@livjm.acdot uk>
To: cambridge-conference <cambridge-conference@livjm.acdot uk>
Subject: CCNet, 24 April 2001
Date: Tue, 24 Apr 2001 13:10:14 +0100
CCNet 59/2001 - 24 April 2001
-----------------------------
[...]
(3) MYSTERY BOOM ROCKS EASTERN AUSTRALIA: AN ATMOSPHERIC IMPACT?
Ron Baalke <baalke@jpl.nasadot gov>
(4) MICRO-METEOROID IMPACTS DAMAGE LEONARDO'S INAUGURAL MISSION
Space.Ref, 23 April 2001
(5) THE LYRIDS METEOR SHOWER OF 2001
Rainer Arlt <rarlt@aipdot de>
[...]
============================================================
(3) MYSTERY BOOM ROCKS EASTERN AUSTRALIA: AN ATMOSPHERIC IMPACT?
>From Ron Baalke <baalke@jpl.nasadot gov>
>From The Courier Mail, 20 April 2001
http://www.thecouriermail.com.au/common/story_page/0,5936,1912401%255E3102,0
0.html
Boom shakes, but fails to stir quake sensor
Staff reporters
20apr01
THOUSANDS thought it was an earthquake, others thought it was a bomb.
Buildings shook, windows rattled, dogs howled.
There were no report of damage, but a mystery boom that rocked a 142km
stretch of the coast in south-east Queensland left lots of worried residents
in its wake.
Earthquake sensors did not register a disturbance, even though the 15-second
"boom" hit thousands of homes between Buderim and North Stradbroke Island.
Earthquake monitoring centres were flooded with calls that a tremor had hit
just after 3.30pm, but no damage was reported.
Last night the RAAF admitted that one of its F-111s had gone supersonic east
of Ballina in NSW. But they played down the chances that the jet was cause
of the boom.
RAAF Wing Commander Rob Lawson said the F-111, flying at 160m, finished its
manoeuvre 100km off the coast at Beenleigh.
He said he could not rule out the possibility that the jet had caused the
"tremor". But "we go supersonic there all the time and people in Brisbane
don't ever notice it," he said.
Air traffic control agency Airservices Australia said last night there was
an area of air space off the coast where military aircraft were permitted to
fly faster than sound.
Spokesman Richard Dudley said while that area did not extend as far north as
Bribie Island, it was possible given certain weather and wind conditions
that the sound of a sonic boom might travel some distance.
"However, that would not explain vibrations people reported experiencing,"
Mr Dudley said.
Relieving Moreton Island ranger Scott Rogers said he was in his office when
the whole building began to shake.
Stradbroke Island resident Mark Davis said his TV shook and his dogs bolted
when the plane flew over his home yesterday at Point Lookout yesterday.
"The dogs were sitting on the loungeroom floor and they freaked, jumped up
and took off out the door," Mr Davis said.
Bongaree resident Darren Jellick said he felt an "enormous shudder and heard
a loud bang" while working at Bribie Island. "It was the sort of sound you
hear when a military bomb blows up," he said.
Bribie Island's Rod Bennett was shaken from sleep.
"I was sure someone was trying to break into the house. It was a really
violent shaking of the windows, I thought they were going to break," Mr
Bennett said.
Copyright 2001, The Courier Mail
============================================================
(4) MICRO-METEOROID IMPACTS DAMAGE LEONARDO'S INAUGURAL MISSION
>From Space.Ref, 23 April 2001
http://www.spaceref.com/news/viewnews.html?id=327
Photos of Two Minor Debris Impacts Leonardo MPLM Suffered on its Inaugural
Mission
By Keith Cowing
These pictures were taken of the Leonardo MPLM (Multi-Purpose Logistics
Module) at NASA KSC after it returned to Earth from its first mission.
Leonardo is one of three MPLM's provided by Italy and was flown to the
International Space Station last month on mission STS-102/ISS-5A.1.
These photos show micrometeoroid damage to a micrometeoroid/orbital debris
(MMOD) shield panel from MPLM FM1 (Leonardo). The panel was penetrated in
two spots (the small pinholes in the photos), but did not damage the
multi-layer insulating blanket beneath. This module was in space for about a
week.
The strike damage to Leonardo's MDPS (micrometeorite protection system) is
characteristic of other impacts that have been seen on spacecraft. However,
the size of particle that penetrated the shield was a bit larger than
average and was estimated to be traveling rather fast - at least 10
kilometers/second - when it struck Leonardo.
To put this impact into perspective, had this piece of space debris hit a
Space Shuttle window it would have left a crater approximately 1 inch (2.5
cm) in diameter. If it had hit a someone wearing an EVA spacesuit it would
have gone partially through the suit and left a bruise on the person wearing
the suit.
Impacts such as these two are routine for any spacecraft in Earth orbit. The
Long Duration Exposure Facility (LDEF) which spent 5.7 years in Earth orbit
had been struck more than 20,000 times by the time its was brought back to
Earth. The Hubble Space Telescope had nearly 800 impacts by the time it was
repaired in 1997.
How much debris a spacecraft can expect to collide with - the orbital debris
flux - is a function of mission duration, the size and orientation of the
spacecraft (how big of a target it is), the orbital inclination, altitude,
and the level of solar activity.
Components of the International Space Station are provided with shielding so
as to reduce the annual risk that impact with a space debris could cause a
critical failure to less than 0.5% This shielding is also sized to last
through the expected 15 year operational lifetime of the ISS.
Last year, it was discovered that the Service Module did not have sufficient
shielding to meet requirements levied upon it by the ISS program. As such,
additional shielding panels will be delivered and installed on the exterior
of the Service Module.
Copyright ) 2001 SpaceRef Interactive Inc. All rights reserved.
============================================================
(5) THE LYRIDS METEOR SHOWER OF 2001
>From Rainer Arlt <rarlt@aipdot de>
-------------------------------------
I M O S h o w e r C i r c u l a r
-------------------------------------
LYRIDS 2001
Very favourable lunar conditions made this shower a highlight target of
2001. Occasionally heightened activity is observed from the Lyrids, most
notably in 1982. The 2001 maximum exhibited a slightly enhanced level of
activity. Observations from 49 observers were collected by April 24, 0h UT.
Such a large number of observations monitoring a shower of moderate activity
is a fairly nice success of amateur meteor observing. The table of the
activity graph is given below.
The maximum is broad; highest rates are found near a solar longitude of
lambda = 32.0 deg with ZHR = 33+-3. The first peak at lambda = 31.7
comprises a number of novice observers
who may have underestimated their limiting magnitudes. Nevertheless, the
up-and-down or -- more roughly speaking -- the general plateau shape of the
activity profile appears to be a typical feature of the 2001 Lyrids. This
was already found in recent Lyrid activity profile. This year, the plateau
may extend over as much as 24 hours. ZHRs in 2000 were lower, 20 at best, in
1999 near 30 as this year, but again significantly lower in 1998 with values
below 20.
- -------------------------------------------------------
2001 Time Sollong nObs nIND nLYR ZHR
Apr (UT) (J2000)
- -------------------------------------------------------
17 0620 27.295 2 1 0 3 +-3
19 0600 29.237 1 1 0 7 +-7
20 0130 30.030 1 1 3 3 +-2
20 2200 30.864 6 2 13 5 +-1
21 0140 31.013 8 5 30 8 +-1
21 1800 31.678 8 7 85 37 +-4
21 2130 31.820 18 13 155 28 +-2
21 2320 31.894 13 13 67 18 +-2
22 0000 31.922 10 10 128 28 +-2
22 0100 31.962 14 12 117 19 +-2
22 0230 32.023 10 10 90 33 +-3
22 0900 32.287 8 5 54 27 +-4
22 2130 32.795 3 2 19 24 +-5
23 2200 33.791 2 2 7 8 +-3
- -------------------------------------------------------
We are very grateful to the following observers for their efforts and quick
reporting of data:
ANTDU Dusan Antic (Serbia) MENHU Huan Meng (China)
ARLRA Rainer Arlt (Germany) MILAA Ana Milovanovic (Serbia)
BASLU Luc Bastiens (Belgium) MISKO Koen Miskotte (Netherlands)
BETFE Felix Bettonvil (Netherlands) MODAM Amruta Modani (India)
BHANE Neha Bhandari (India) NISMA Markku Nissinen (Finland)
BHASU Sushrut Bhanushali (India) PATSO Sonali Patil (India)
DECGO Goedele Deconink (Belgium) PEEBJ Bjorn Peeters (Belgium)
DEOPA Parag Deotare (India) PRAMA Mayuresh Prabhune (India)
DUBAU Audrius Dubietis (Lithuania) PUNNI Nilesh Puntambekar (India)
FANYU Yuwei Fan (China) RENJU Juergen Rendtel (Germany)
GADSH Shirish Gadkar (India) SAVBR Branislav Savic (Serbia)
GEOPE Petros Georgopoulos (Greece) SONWA Wanfang Son (China)
GEYBE Benny Geys (Belgium) SUNHU Huiming Sun (China)
GLIGE George Gliba (USA) TRIJO Josep Trigo-Rodriguez (Spain)
GOLDA Darja Golikowa (Germany) TUKAR Arnold Tukkers (Netherlands)
HASTA Takema Hashimoto (Japan) UCHSH Shigeo Uchiyama (Japan)
JOHCA Carl Johannink (Netherlands) VELKR Kristina Veljkovic (Serbia)
KULMA Manali Kulkarni (India) VERJN Jan Verbert (Belgium)
KULRH Rhikesh Kulkarni (India) VUJKA Katarina Vujic (Serbia)
KULVI Vineet Kulkarni (India) VUJRO Romana Vujasinovic (Serbia)
LANMA Marco Langbroek (Netherlands) WANSH Shuo Wang (China)
LINMI Mike Linnolt (USA) WISJE Jean-Marc Wislez (Belgium)
LUNRO Robert Lunsford (USA) ZERZO Zorana Zeravcic (Serbia)
MARAN Antonio Martinez (Venezuela) ZHUJI Jin Zhu (China)
MCBAL Alastair McBeath (UK) ZUPLJ Ljubica Zupunski (Serbia)
Solar longitudes refer to equinox J2000.0. nObs is the number of individual
observing periods, nIND is the number of individual observers providing
them, nLYR is the number of Lyrids seen. The radiant position was assumed at
alpha=271, delta=+34, the population index used was r=2.9. The expectation
value of the ZHR,
ZHR = (1 + sum nLYR) / sum(Teff/C),
was used for the averages here, where Teff is the effective observing time
and C is the total
correction composed of limiting magnitude, clouds, and zenith correction.
Times are rounded to
the nearest 10 minutes.
Rainer Arlt & Vladimir Krumov,
2001 April 24
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