LIST CONTENT

        The TLE (two-line elements) file published once a week, usually on Saturday or Sunday (when I'm available), is intended to help make pass predictions for those who want to observe special objects. These objects are composed of satellites, rocket stages and debris of diverse nature that vary rapidly in brightness. Most of them will flash or have regular brightness variations with a period between 0 and 2 seconds. This is what makes them attractive and easy to spot among the other visible satellites that are of constant brightness or varying more slowly. Those who have a satellite tracking software installed on their computer can use this TLE list to make their own pass predictions.

        The TLE are sorted by USSC catalog number. Only one object, EGP, has a spherical body covered with a lot of square metallic mirrors, hence the nickname "disco ball" in reference to the mirror balls we see in night clubs. Because of its rotational speed and the position of its mirrors, it can produce up to 3 flashes per second ! Keep in mind that the flashes are produced by the Sun reflecting on the mirrors, so the satellite needs to be illuminated to produce them.

        The other objects on this list are inoperative satellites, rockets bodies or all kinds of space debris. Most operational satellites are of constant brightness. When a satellite attitude control system fails or has expanded all of its fuel, the satellite starts to tumble and becomes a flasher. Many rocket stages can become fast flashers when they vent their remaining onboard fuel, like it is the case with the Russian SL-16 rocket second stage.

        Only one object on the list is not a fast flasher, the International Space Station (ISS). It is included because it is the brightest artificial satellite orbiting the Earth and attracts a lot of attention. It's an easy object and it too can produce flares from time to time due to its complex shape and numerous large flat surfaces.

        You can contribute to the photometric study of these objects for the Belgian Working Group Satellites (BWGS) by reporting your visual observations. A description of the PPAS format used to make the reports is here.
 

DESCRIPTIONS

        The following object descriptions give some details about the different designations, the origin, the visual characteristics and how to best observe each satellite in the list. These objects appear in the same order they are posted in the TLE list and are designated by their common name.

TITAN 3C TRANSTAGE R/B
USSC catalog number : 1863
International designation : 1965-108A
Launch date : December 21, 1965
Country of origin : U.S.A.
Description : Third stage from the Titan IIIC rocket that left on their transfer orbit the satellites OV2-03, LES 3, LES 4 and Oscar 4 because of a malfunction. Also named Transtage 8. Diameter : 3 m,   length : 4.6 m,   empty mass : 1 950 kg.
Web page
Visual characteristics : Reported period of 0,7 second on November 6, 2004.
Observation method : Telescope

ATLAS CENTAUR R/B
USSC catalog number : 5816
International designation : 1972-003B
Launch date : January 23, 1972
Country of origin : U.S.A.
Description : Second stage (Centaur D-1 A model) from the Atlas Centaur SLV-3C that orbited the Intelsat 4-F4 communications satellite. Diameter : 3.1 m,   length : 9.6 m,   empty mass : 2 630 kg.
Web page
Visual characteristics : 1.6 second period. Max. magnitude of 7.
Observation method : Large binoculars or telescope

KH 9-17 ELINT
USSC catalog number : 13172
International designation : 1982-041C
Launch date : May 11, 1982
Country of origin : U.S.A.
Description : Signals intercept satellite orbited as a secondary payload with 1982-041A, a large Hexagon film return imaging spy satellite.
Visual characteristics : 1.5 second period. Magnitude varying from 5 to 7.
Observation method : Binoculars

USA 3
USSC catalog number : 15071
International designation : 1984-065C
Launch date : June 25, 1984
Country of origin : U.S.A.
Description : 60 kg surveillance satellite also known as Farrah 5.
Visual characteristics : Period under one second. Magnitude from 5 to invisible.
Observation method : Binoculars

EGP
USSC catalog number : 16908
International designation : 1986-061A
Launch date : August 12, 1986
Country of origin : Japan
Description : Geodetic satellite having a spherical diameter of 2.15 m and covered with 318 mirrors and 1436 laser retroreflectors. Also known as Ajisai or EGS.
Web page
Visual characteristics : The most spectacular of all flashers. Groups of 2 or 3 magnitude 5 to 7 flashes in one second.
Observation method : Binoculars

USA 32
USSC catalog number : 19460
International designation : 1988-078A
Launch date : September 5, 1988
Country of origin : U.S.A.
Description : US Navy surveillance satellite also known as NOSS 1-9.
Web page , web page
Visual characteristics : Period of about 2 seconds. Magnitude between 5.5 and 7.
Observation method : Binoculars

STTW
USSC catalog number : 21833
International designation : 1991-088A
Launch date : December 28, 1991
Country of origin : China
Description : Communications satellite left on a wrong orbit after launch. Number 5 in the STTW series, it is also known as PRC 34. Diameter : 2.0 m,   length : 2.4 m,   mass : 1 025 kg.
STTW = Shiyan Tongbu Tongxing Weixing
Web page
Visual characteristics : One second period. Few observations reported.
Observation method : Binoculars

USA 81
USSC catalog number : 21949
International designation : 1992-023A
Launch date : April 25, 1992
Country of origin : U.S.A.
Description : Presumably an electronics and signals intelligence satellite for the US Air Force.
Web page
Visual characteristics : Period of about 1.5 second. Magnitude between 5 and 7.
Observation method : Binoculars

FAST
USSC catalog number : 24285
International designation : 1996-049A
Launch date : August 21, 1996
Country of origin : U.S.A.
Description : Fast Auroral SnapshoT Explorer. Polar auroras study satellite of 1 m diameter and length and with a mass of 191 kg.
Web site
Visual characteristics : Occasional fast flashes coming from its solar panels while the satellite spins at 12 rpm.
Observation method : Binoculars

DMSP 5D-2 F14 DEB
USSC catalog number : 24777
International designation : 1997-012D
Launch date :
Country of origin : U.S.A.
Description : Debris of unknown nature coming from the DMSP 5D-2 F14 defense meteorological satellite.
Web page
Visual characteristics : Period of about 1.5 second. Magnitude from 5 to invisible.
Observation method : Binoculars

IRIDIUM 920
USSC catalog number : 24871
International designation : 1997-034C
Launch date : July 9, 1997
Country of origin : U.S.A.
Description : Mobile phone communications satellite with a triangular body of 1 m wide by 4 m high and covered with many flat reflecting surfaces, including its three main mission antennas. Out of control and tumbling since its launch.
VSOHP page , web site
Visual characteristics : Period of about 1 second but irregular. Magnitude up to 0.
Observation method : Naked eye

SCD 2
USSC catalog number : 25504
International designation : 1998-060A
Launch date : October 22, 1998
Country of origin : Brazil
Description : Environmental data relay satellite having a diameter and length of 1 m and a mass of 117 kg.
Visual characteristics : Occasional fast flashes (up to mag 4 and P=0.3 s) due to the 34 rpm satellite rotation.
Observation method : Binoculars

ISS
USSC catalog number : 25544
International designation : 1998-067A
Launch date : November 20, 1998
Country of origin : U.S.A. and Russia
Description : International Space Station. Construction not yet completed.
NASA web site
Visual characteristics : In this list because of its brightness and the interest of observing it. Occasional flares of up to mag 5 from one of its many flat surfaces.
Observation method : Naked eye

MSTAR 3 CENT RK
USSC catalog number : 25725
International designation : 1999-023B
Launch date : April 30, 1999
Country of origin : U.S.A.
Description : Third stage (Centaur G) from the Titan 4B rocket that placed in a wrong orbit the Milstar 3 military communications satellite following premature firings of the stage engines. Diameter : 4.3 m,   length : 9.0 m,   empty mass : 2 775 kg.
Web page , Titan IV rocket page
Visual characteristics : 1.4 second period. Magnitude from 7 to invisible.
Observation method : Large binoculars

TERRIERS
USSC catalog number : 25735
International designation : 1999-026A
Launch date : May 18, 1999
Country of origin : U.S.A.
Description : Boston University ionosphere and thermosphere study satellite with a mass of 125 kg. An attitude control system malfunction caused the batteries to drain all their power and the loss of the satellite on its second orbit. TERRIERS is the acronym for Tomographic Experiment using Radiative Recombinative Ionospheric Extreme ultraviolet and Radio Sources.
Web site
Visual characteristics : Observed either stable or having a period of 1.3 second. Magnitude 7.
Observation method : Large binoculars

BSAT-2B
USSC catalog number : 26864
International designation : 2001-029B
Launch date : July 12, 2001
Country of origin : Japan
Description : TV satellite put in a wrong orbit by the EPS stage of its Ariane 510 launcher. Body size : 3.7 x 2 x 2 m, solar wing total span : 16 m. Mass : 1 300 kg.
Web page (in French with pictures)
Visual characteristics : Observed in 2004 with a period of about one second.
Observation method : Binoculars

RUBIN 3 / SL-8
USSC catalog number : 27561
International designation : 2002-054C
Launch date : November 28, 2002
Country of origin : Germany / Russia
Description : 45 kg German space research microsatellite left attached to its Russian Kosmos-3M rocket second stage.
Web page
Visual characteristics : 2.2 seconds period. Magnitude from 4 or 5 to invisible.
Observation method : Binoculars

MILSTAR 6 CR
USSC catalog number : 27712
International designation : 2003-012B
Launch date : April 8, 2003
Country of origin : U.S.A.
Description : Third stage (Centaur G) from the Titan 4B rocket used to put in orbit the Milstar 6 military communications satellite. Diameter : 4.3 m,   length : 9.0 m,   empty mass : 2 775 kg.
Web page , Titan IV rocket page
Visual characteristics : Near-geosynchronous, moves eastward about one degree per day. 1.6 second period. Max. magnitude of 9.
Observation method : Telescope

COSMOS 2400 R
USSC catalog number : 27870
International designation : 2003-037C
Launch date :  August 19, 2003
Country of origin : Russia
Description : Second stage from the Kosmos-3M (SL-8 or 11K65M) rocket used to orbit two Strela-2-type military communications satellites, Cosmos 2400 and 2401. Diameter : 2.4 m,  length : 6.0 m,  empty mass : 1 435 kg.
Web page
Visual characteristics : Observed on January 7, 2005 with a period of 1.8 s and a magnitude varying from 5 to invisible. Its flash period is still getting shorter.
Observation method : Binoculars

SL-16 R/B
USSC catalog number : 28353
International designation : 2004-021B
Launch date :  June 10, 2004
Country of origin : Russia
Description : Second stage from the Zenit-2 (SL-16 or 11K77) rocket used to orbit the Cosmos 2406 Tselina-2-type ELINT satellite. Diameter : 3.9 m,  length : 11.5 m,  empty mass : 9 000 kg.
Zenit-2 Web page
Visual characteristics : Observed on June 19, 2004 with a period of 0.6 s and a magnitude of 2. Its period will be ever increasing until it becomes visually steady. Period was nearing 2 sec on January 6, 2005.
Observation method : Naked eye
 
 

Last update of this page : January 9, 2005 , 17:30 UTC

Author : Daniel Deak
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Visit the French language satellite web site : Obsat.com