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SAT-MidEast 98.08.14
WELCOME TO SAT-MIDEAST !
A news release from Cairo, Egypt, located at 31.15 East - 30.3 North,
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WHAT YOU'LL FIND HERE:
- Events and News interesting to the Middle Eastern SAT-viewer
- Satellite and Transponder Observations in C- and Ku-Band,
- Everything commented from the Middle Eastern perspective
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HUGHES SCP INVESTIGATION
------------------------
Hughes Electronics Corporation last Tuesday announced that launches of
its HS 601 communications satellites are ready to resume after an
extensive investigation revealed that electrical shorts involving
tin-plated relay switches are the most likely cause of three spacecraft
control processor (SCP) failures on in-orbit satellites.
Hughes began incorporating improved relay switches and related processes
on its satellites several years ago. The company has notified PanAmSat
Corp. and Societe Europeenne des Satellites that they can proceed with
their launches of Galaxy X and Astra 2A, respectively. The satellites
are manufactured by Hughes Space and Communications Co. (HSC).
"Our investigation team was very diligent in its pursuit of the probable
cause, and we are confident that this scenario will not be repeated in
the satellites that are being built and launched today," said Michael T.
Smith, chairman and chief executive officer of Hughes Electronics.
"While our investigation cannot rule out the possibility that another
currently operating SCP could fail, the probability of both SCPs failing
on one in-orbit HS 601 satellite is very low."
"With this in mind, on Monday the Hughes Electronics board of directors
endorsed plans to strengthen the robustness of the PanAmSat and DIRECTV
satellite fleets," said Smith. "These plans will provide our satellite
services customers a very high level of assurance of continuity of
service, while preserving Hughes' long-term growth opportunities."
The Hughes board endorsed PanAmSat's announced strategy to modify two
satellites already under construction for the U.S. market and procure
four communications satellites, two of which will serve as spares on the
ground. The Hughes board also approved the acquisition of a fourth
direct broadcast satellite by DIRECTV Inc. The satellites, pending
approval by the Federal Communications Commission, are expected to be
launched in the latter half of 1999.
Of the satellites that experienced a failure of an SCP, two - Galaxy VII
and DBS-1 - are operating normally with backup SCPs. The third, Galaxy
IV, suffered the loss of both SCPs and has been removed from service.
The second SCP failure on Galaxy IV is distinctly different from the
other three and is viewed as a random event. Galaxy IV was the first
operational HS 601 model satellite to suffer a complete failure. Since
1963, Hughes satellites have provided more than 1,000 years of
cumulative on-orbit service to customers worldwide with a channel
availability of more than 99 percent.
A team of Hughes engineers and outside experts confirmed that all three
satellites experienced an electrical short within the SCP, resulting in
blown fuses. The SCP is the on-board computer that controls the
satellite. It executes a number of critical functions, such as
propulsion for attitude control, solar wing positioning and antenna
pointing. Hughes installs two SCPs, as well as other redundant systems,
on each satellite to assure long life and reliability.
The investigators have narrowed down the most probable cause to a
tin-plated latching relay that serves as an on/off switch within the
SCP. Under certain conditions, a tiny, crystalline structure, less than
the width of a human hair, can grow and bridge a relay terminal to its
case, causing an electrical short.
For this to occur, however, a number of factors must be concurrently
present. Those factors include the presence of pure tin, incomplete
protective coating leaving part of the tin relay exposed, and a grounded
relay case. Additionally, other factors with a finite probability of
happening must also be present for a short to occur. There must be
localized stress in the tin plating to precipitate the growth of the
crystalline structure, and the structure must grow a sufficient length
and in a certain direction.
"Manufacturing records and photos are being scrutinized to narrow the
number of in-orbit satellites that are possibly susceptible to the
phenomenon, and we are investigating possible actions that might reduce
the probability of recurrence in orbit," said HSC President Donald L.
Cromer.
When Galaxy IV became inoperable May 19, it had been in orbit nearly
five years. On June 14, Galaxy VII switched over to its redundant SCP
and is operating normally. It has been in orbit since October 1993. Both
Galaxy satellites are owned by PanAmSat. On July 4, DIRECTV's DBS-1
spacecraft also switched over to the redundant SCP without any loss of
service and is operating normally. It was launched in December 1993.
The HS 601 is the world's most popular large satellite model. There are
35 HS 601 spacecraft in orbit and 30 under construction or awaiting
launch. Hughes has inspected the SCPs on those satellites pending launch
and has confirmed their flight worthiness.
(SME, source: Hughes Electronics Corp. PR)
LEONID METEOR SHOWER
--------------------
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 earth's 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 last for a span of two to six hours,
and can be fairly accurately estimated. This years peak is expected on
November 17th, approximately 20:00 CET.
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.
The announcement indicates that all users of satellite assets should
monitor their systems very carefully during a period of November 17th,
12:00 CET to November 18th, 0200 CET. This period is six hours prior to
and six hours after the expected height of the meteor storm.
(SME, source LS)
SOHO: BACK to LIFE, BACK to REALITY
-----------------------------------
Six days after receiving the first signal from the dormant SOHO
Spacecraft, several blocks of telemetry data giving the spacecraft's
on-board status were acquired late Saturday night, 8 August, at 23:15
hrs GMT. Further data acquisitions took place on Sunday 9 August and
will continued in the following days.
"This is the best news I've heard since we lost contact with SOHO on 25
June" said Roger Bonnet, ESA's Director of Science. "I never gave up
hope of some recovery of this fantastic mission. We should just hope
that the damage sustained by SOHO's enforced period of deep freeze does
not affect the scientific payload too much."
Following analysis of the expected on-board conditions by engineers from
the European Space Agency and Matra Marconi Space (builders of the SOHO
spacecraft) a series of command sequences was up-linked through the NASA
Deep Space Network (DSN) station at Goldstone, CA. These sequences were
designed to divert the available solar array power into a partial
charging of one of the on-board batteries.
After 10 hours of battery charging, the telemetry was commanded on and
seven full sets of data of the on-board status were received. After one
minute telemetry was switched off from ground controllers in order to
preserve on-board resources. Further details on the on-board conditions
were obtained the following day (Sunday 9 August) in two subsequent
telemetry acquisitions lasting four and five minutes respectively. Data
gathered included information on temperature and voltages for payload
instruments, which are currently being analysed.
With the battery charging technique proven successful, the team has
requested a full 24-hour coverage of SOHO to attempt a more complete
charging. The NASA DSN has accepted this request as a "Spacecraft
Emergency" giving it priority over other DSN scheduled activities. The
procedure is on-going.
ESA's Francis Vanderbussche, in charge of the SOHO Recovery Team at
GSFC, said: "I am truly satisfied with the information the data we
acquired gives us. Conditions on-board are as good as we expected them
to be." At the moment the team is working on the next series of
procedures which will be aimed at thawing the on-board hydrazine fuel to
enable attitude control of the spacecraft to be re-established. This
will be attempted once full charge can be established in both on-board
batteries later this week.
Radio contact with SOHO, a joint mission of ESA and NASA, was
interrupted on 25 June 1998. The delicate recovery activities are being
directed by the ESA SOHO project team from the NASA Operation Centre at
GFSC.
SOHO had completed its nominal two-year mission in April 1998. The
spacecraft has already achieved spectacular results concerning the
dynamics of the solar interior and has given a comprehensive view of the
solar corona. Its mission had recently been extended to 2003 to cover
the upcoming period of maximum solar activity expected to peak in 2001.
(SME, source: ESA PR)
APSTAR 2R, 76.5 East, http://www.satcodx.com/apstar2r.shtml
---------
* Chinese entertainment channel TVB 8 started on 3,760 H, PAL/clear,
6,60:7,20 MHz. It is moderated fully in Mandarin and seems to be based
on western styled music arrangements with Chinese texts. TVB 8 studios
and uplink are in Hong Kong.
The received quality is as expected excellent in Cairo with 240 solid
dish. Reports show that the channel can be received spark-free up to
northern Europe.
(SME)
PANAMSAT 4, 68.5 East, http://www.satcodx.com/pas4.shtml
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* RTP International on 4,113 V as part of the Multichoice Africa package
is now encrypted in IRDETO.
(SATCO DX)
EUTELSAT II-f1, 13 East, http://www.satcodx.com/e2f1.shtml
--------------
* Fashion TV in PAL has moved from 11,638 H to Hot Bird 2.
(SATCO DX)
* Bloomberg TV has started on 11,642 H, MPEG-2/clear, SR 27500, FEC 3/4,
additonal to transmissions on Eutelsat II-f2 at 11,575 V.
1160/1120: Bloomberg TV France
1260/1220: Bloomberg TV Italy
1360/1320: Bloomberg TV Spain
1460/1420: Bloomberg TV Germany
1560/1520: Colour bars
(SATCO DX)
HOT BIRD 2, 13 East, http://www.satcodx.com/hb2.shtml
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* Fashion TV has replaced the digital RAI tests on 11,766 V, PAL/clear,
6,60 MHz.
The audio is from CMR - Country Music Radio though, so it must be
assumed that this is a backhaul from Hot Bird 3, transponder 74, 12,188
V.
(SATCO DX)
* SME Comment: I suspect this occupation to be of a very temporary
nature, and that actually Fashion TV is just carried in order to submit
CMR to a broader forum, due to a Worldwide Radio Festival with the
cooperation of Merlin Network One
(see also http://www.merlincommunications.com/)
HOT BIRD 3, 13 East, http://www.satcodx.com/hb3.shtml
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* TGRT has replaced Canal 24 Horas in the Telespazio DP on 12,111 V,
MPEG-2/clear, PIDs 210/211, SID 702.
(SATCO DX)
HOT BIRD 4, 13 East, http://www.satcodx.com/hb4.shtml
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* Saudi Channel 1 has started on 12,654 H, MPEG-2/clear, PIDs 1760/1720,
SID 7, poorer picture than on SID 3.
(SATCO DX)
* San Marino RTV tests and Krisma have left the Skyplex test transponder
110.
Sardegna Uno from Italy, has therefore started testing on 10,719 V,
MPEG-2/clear, PIDs 4865/4866.
(SATCO DX)
* Quantum 24 on 10,914 H, (still superbeam) has following languages
lined-up:
1220 left: English
1220 right: German
1222 left: Dutch
1222 right: French
(SATCO DX)
INTELSAT 707, 1 West, http://www.satcodx.com/i707.shtml
------------
* The Israeli package on 11,015 V has changed its SR to 10000.
(SATCO DX)
* SME Comment: This (test) package has changed it's Symbol Rate more
often temporarely, so it could easily change back in a few days.
NILESAT 101, 7 West, http://www.satcodx.com/nile101.shtml
-----------
* Iraq Satellite Channel returned to 11,862 V in PAL as well as on
11,823 V in MPEG-2.
(SATCO DX)
* ERTU 5 has started on 11,843 H, MPEG-2/clear, PIDs 1008/1208, SID 608.
A further test card has started on PIDs 1009/1209, SID 609.
(SATCO DX)
For all the loved ones overseas here the following two messages (these
channels are NOT receivable in the Middle East).
PANAMSAT 5, 58 West, http://www.satcodx.com/pas5.shtml
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* LBC America and LBC Australia have started on 4,120 V, MPEG-2/clear.
Here is the complete line-up, with SIDs and PIDs:
100/512/650: ART America
110/513/660: ART 4 - Movies
120/514/670: LBC America
130/515/680: RAI Int. (America)
140/516/690: LBC Australia
150/517/700: ART Australia
160/518/710: RAI Int. (Australia)
170/519/720: MCM
(SATCO DX)
* SME Comment: How the Australian version from PAS-1 are transferred to
the Pacific Region is not known by me, I guess via the US Panamsat
uplink center to PAS-2 at 169 East.
GALAXY 3R, 95 West, http://www.satcodx.com/g3r.shtml
---------
* EABC has started with a multi-national digital package on 11,720 H,
DSS/News Datacom, part of the line-up are ESC 1 & Nile Drama Channel
both from Egypt.
For the complete line-up and reception details, please see the SATCO DX
chart.
(SATCO DX)
Best regards,
Henk C. Room / Cairo - Egypt
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