BY SPACEFLIGHT NOW
August 17, 2000 -- Follow the preparations and launch of the Brasilsat B4 and Nilesat 102 communications satellite aboard an Ariane 4 rocket. Reload this page for the very latest on the mission.
2342 GMT (7:42 p.m. EDT)
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In about 2 1/2 minutes, the SPELDA adapter used to connect the two satellite payloads will be released. Deployment of Nilesat 102 is expected 26 minutes, 14 seconds.
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The Libreville tracking station in Africa has acquired the Ariane 4 rocket.
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The Ascension Island tracking station in the Atlantic Ocean has acquired the rocket's signal as it heads eastward away from South America.
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Also, the rocket is now passed out of range from the tracking station in Kourou.
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In the final seconds of the countdown, activities will include releasing the inertial platform at minus 9 seconds, and the release command to the retraction system for the two cryogenic arms will be given at minus 5 seconds.
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In the next half-minute, the launch time will be loaded aboard the Ariane rocket's guidance system. Also, the Nilesat 102 and Brasilsat B4 spacecraft will be confirmed on internal power and declared ready for launch.
2310 GMT (7:10 p.m. EDT)
During the next six minutes, the Ariane 44LP rocket, satellite payload and ground systems will be configured for launch. There are two master computers running the countdown. One is responsible for fluids and propellants and the other for final preparation of the electrical systems such as initiating the flight program, activation of the engine steering systems and power transfer from ground supplies to onboard batteries. The computers will control until minus 5 seconds when a majority logic sequencer takes over for first stage and liquid strap-on booster engine start at zero seconds. Engine performance checks are done in parallel by the two computers starting at plus 2.8 seconds. Finally, the command will be issued to open the launch table clamps for liftoff between ignition +plus 4.1 and 4.6 seconds.
2308 GMT (7:08 p.m. EDT)
The computer-run synchronized sequence to launch will start in two minutes.
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A network of tracking stations are standing ready to relay data from the Ariane 4 rocket to engineers in Kourou. The early portion of flight will be monitored through the Kourou and Cayenne stations in French Guiana. About 6 minutes, 15 seconds into flight the Natal station in Brazil will pick up the rocket's signal as the third stage burn gets underway. At plus 12 minutes, 55 seconds the site on Ascension Island in the Atlantic Ocean will begin coverage. Libreville in Gabon will provide services for spacecraft separation and the conclusion of Arianespace Flight 130.
2301 GMT (7:01 p.m. EDT)
THURSDAY, AUGUST 17, 2000
Flight 131 will place the Brasilsat B4 and Nilesat 102 communications into a highly elliptical geostationary transfer orbit. During the nearly 30-minute ride to orbit, Brasilsat B4 will sit in the upper position, while Nilesat 102 will be in the lower slot of the SPELDA dual-payload carrier inside of the Ariane payload fairing.
The Hughes-built Brasilsat B4 will serve in orbit for EMBRATEL, the leading Brazilian telecommunications company. "The Brasilsat B program is a success story, not only with the long-standing engineering cooperation but also with the growth of EMBRATEL into the largest satellite operator in Latin America," Tig H. Krekel, President and CEO of Hughes Space and Communications, said of the partnership between EMBRATEL and Hughes and of the success of previous Brasilsat satellites. Once in orbit, its 28 C-band transponders will provide mainly voice and data traffic for Brazilian users. Based on the Hughes 376W design, Brasilsat B4 will weigh 3,865 pounds at launch. During its 12-year lifetime, it will be positioned at 92 degrees West longitude in geostationary orbit, where it will join five other Brasilsat spacecraft. All were launched aboard Ariane rockets. Brasilsat B4 is specifically replacing Brasilsat A2 -- launched in March 1986.
Nilesat 102 was manufactured by Astrium, a European consortium that was formed by the recent merger of Matra Marconi Space and the space divisions of Daimler Chrysler, the European auto-maker. Its main payload, the 12 Ku-band transponders and related gear, was built under contract by Alcatel Space of France. Weighing 4,019 pounds at launch, Nilesat 102 will provide digital and direct-to-home television programming to customers in northern Africa and surrounding regions. Its operator, the Egyptian Nilesat company, already has one satellite in orbit -- Nilesat 101. Nilesat 101 was launched aboard an Ariane 4 rocket on Flight 108 in April of 1998.
According to Arianespace mission manager Jean-Marc Artaud, all is well with the launcher and its payloads. The Flight 131 mission manager also stated that the launch readiness review was successfully completed on Monday, but not until two last minute technical problems could be resolved. One problem included the replacement of plastic ties and bundles that keep electrical wires and cables running together and the other problem involved an anomalous reading during a test on the launch vehicle last week.
Yesterday, workers loaded the and first and second stages, as well as the two liquid-fueled boosters, with their storable unsymmetrical dimethyl hydrazine and nitrogen tetroxide fuel combination. The third stage and its Snecma-built HM-7B engine is fueled by liquid oxygen and liquid hydrogen. The solid-fueled strap-on boosters were loaded with their flexadine powder propellant during their manufacturing.
Both satellite payloads are undergoing battery charges at the launch pad as they await their thunderous climb into space.
Later today, the final countdown is set to begin at 0846 GMT (4:46 a.m. EDT). The large 321-foot service gantry that has covered the launcher during its stay at the launch pad will be retracted at 1721 GMT (1:21 p.m. EDT). Filling operations for the cryogenic third stage and its liquid oxygen oxidizer and liquid hydrogen fuel will commence at 1941 GMT (3:41 p.m. EDT). Launch controllers in the Jupiter launch control room will bring to life the rocket's telemetry, radar transponders, telecommand systems, and associated hardware at 2211 GMT (6:11 p.m. EDT). With no problems standing in the way of a successful launch, controllers will allow the Synchronized Launch Sequence to begin at Launch Minus-6 minutes at exactly 2310 GMT (7:10 p.m. EDT). Following the beginning of the final launch sequence is a series of fast-paced events, culminating in the ignition of the first stage and liquid-fueled strap-on boosters, then the ignition of the solid-fueled strap-on boosters just over four seconds later -- signaling liftoff.
After launch, the vehicle will take a normal Ariane 44LP ascent profile with one- and two-minute burns of the solid- and liquid-fueled strap-on boosters, respectively. Following the jettison of all four boosters, the first stage, second stage, and third stage will complete their burns to place the Brasilsat B4 and Nilesat 102 payloads into their proper orbit. First to separate from the third stage will be Brasilsat B4, followed around five minutes later by Nilesat 102.
Be sure to stay with Spaceflight Now for launch this evening. Our live updates will begin around 30 minutes prior to launch.
TUESDAY, AUGUST 15, 2000
The mating of the Brasilsat B4 and Nilesat 102 payloads to the top of the Ariane 4 launcher took place on Friday, August 11. The mating took place atop the ELA-2 service gantry.
The two spacecraft were encapsulated in their payload fairing during the middle of last week. Inside of the fairing, Brasilsat B4 is positioned in the upper slot of the SPELDA dual-payload carrier and will be separated first. Nilesat 102 sits in the lower position and will be separated last.
Over the past week, Arianespace had to change their launch campaign to accommodate a last-minute problem with the Brasilsat B4 spacecraft. Technicians responsible for the Brasilsat payload discovered a problem with a strut on the craft. A replacement was flown to Kourou two weeks ago and the change-out occurred during the weekend following August 4. Validations were made early last week, and the launch campaign was allowed to restart. In the midst of this flurry of activity, the launch countdown rehearsal took place on August 4, signaling the start of combined operations at the launch site -- the busiest part of the entire campaign.
Workers spent yesterday making final checks on systems at the launch pad, the satellites, and the launch vehicle. Today will be spent doing similar activities.
On Wednesday, the first and second stages and the two liquid-fueled strap-on boosters of the Ariane 44LP will be loaded with their nitrogen tetroxide oxidizer and unsymmetrical dimethyl hydrazine propellant. The third stage will be loaded with its liquid oxygen oxidizer and liquid hydrogen fuel combination on Thursday -- launch day. The two solid-fueled strap-on boosters were fueled during construction with their bonded solid fuel combination.
Brasilsat B4 was built by Hughes Space and Communications of El Segundo, California, and will be operated by EMBRATEL, the leading Brazilian telecommunications company. The satellite is based on the Hughes 376W design, and is shaped like a cylinder. The craft will use its 28 C-band transponders to handle voice and data transmissions both to and from Brazil. During its 12-year lifetime, it will be positioned above the Galapagos Islands in the Pacific Ocean. Once operational, it will replace the aging Brasilsat A2 satellite -- launched in March 1986 aboard an Ariane vehicle. It will be the sixth spacecraft in the entire Brasilsat fleet.
Nilesat 102 was built by Astrium, a European company formed by the mergers of the space divisions of Daimler Chrysler and Matra Marconi Space. Taking the now-familiar look of communications satellites with two large solar arrays, Nilesat 102 will join Nilesat 101 in orbit above northern Africa for the Nilesat company of Egypt. Its 12 Ku-band transponders will broadcast digital direct-to-home television programming to viewers across the northern regions of the African continent, the Mediterranean Sea, and the Arabian peninsula. The Ku-band repeaters were built by Alcatel Space of France. Nilesat 102 will positioned at 7 degrees West longitude. It is being put into orbit as part of a turnkey contract won by Astrium.
Launch of Flight 131 is set for Thursday evening during a launch window that opens at 2316 GMT and closes at 2358 GMT (7:16 to 7:58 p.m. EDT).
Stay with Spaceflight Now throughout the next few days for continued updates. Also, be sure and stop by on launch day for play-by-play updates throughout the countdown and launch.
SUNDAY, AUGUST 6, 2000
The launch campaign entered its final phase on Tuesday as the launch vehicle was transferred from the ELA-2 assembly hall to the ELA-2 launch zone, where it will stay until launch in just under two weeks. The rocket's mobile launch table carried the launcher on its journey.
After the launch table was locked down and into place at the pad, the service gantry was put into place around the rocket. The gantry provides workers access to most parts of the rocket and protects the vehicle during pre-launch processing. Barring any problems, the service tower will not be rolled back to reveal the rocket until just a few hours before launch.
The first of the two solid-fueled strap-on boosters was attached to the vehicle on Wednesday, followed by the second the next day.
The processing campaign was kicked off back on July 12 with the traditional review of the readiness to begin the fast-paced processing schedule. Also on July 12, the first stage was erected, followed by the second stage, liquid-fueled strap-on boosters, third stage, and vehicle equipment bay throughout the following week.
With the propulsion system fully assembled, all that remains are the two payloads and their protective fairing. The two spacecraft, Brasilsat B4 and Nilesat 102, were fueled with their propellant over the past weekend.
Looking ahead, the two payloads will be integrated into the dual payload support system, then encapsulated into the payload fairing. The entire process takes two days to complete.
The entire payload section of the rocket--including the two spacecraft, associated hardware, and the payload fairing--will be transferred from the satellite processing facility to the launch pad on Wednesday. For August 10, the payload section will be mated atop the rocket. Also slated for next Thursday is a launch rehearsal.
A launch readiness review is set for August 11, followed shortly thereafter by launcher arming -- a sign that the mission has been cleared for launch.
After a quiet weekend, the rocket's first stage, second stage, and two liquid strap-on boosters will be fueled with their storable propellant and oxidizer on August 16.
On August 17, countdown activities will commence early in the day. Also, the third stage will be fueled with its liquid oxygen and liquid hydrogen fuel combination shortly before launch.
Built by the newly formed Astrium, Nilesat 102 will aim its 12 Ku-band transponders on northern Africa during its 12-year lifetime. The spacecraft will operate in geostationary orbit at 7 degrees West longitude for the Egyptian Nilesat SA company on a mission to deliver television programming direct-to-home. With its solar wings fully deployed, Nilesat 102 will feature a wing-span of around 60 feet. At launch, Nilesat 102 will weigh 4,019 pounds.
Brasilsat B4 is the fourth in a series in a add-on series of spacecraft for the Brazilian EMBRATEL satellite operator, all of which were built by Hughes Space and Communications. Based on the 376W design, the craft will weigh 3,865 pounds at lift-off, but will weigh much less once it consumes a large amount of fuel to arrive at its correct orbit after separating from the Ariane third stage in geostationary transfer orbit. Brasilsat B4 will use its 28 C-band transponders to relay information throughout Brazil.
During the nearly half-hour ride into orbit, Brasilsat B4 will be positioned on top of the dual payload carrier and thus will be separated first. Nilesat 102 will be on the bottom and will be detached last.
Stay with Spaceflight Now during the coming days for continuing coverage of the processing flow and of the countdown and launch on August 17.
THURSDAY, JULY 27, 2000
It actually will be the 130th Ariane mission after the scheduled late-July launch of an Ariane 5 was delayed until September due to concerns with the vehicle's upper stage. Since the Ariane 5 had progressed into its launch campaign, it will keep the Flight 130 designation.
After the Ariane 4's Flight 131 launch campaign began on July 12, the core stage first and second stages were erected, as well as the first of two liquid-fueled strap-on boosters. The second of the two was mated to the bottom of the first stage on July 19. On July 20, the third stages was placed atop the second stage, followed by the launcher's vehicle equipment bay. Commonly called the "brains" of the rocket, the equipment bay contains all of the command and control systems.
One of the Ariane 4's payloads -- Brasilsat B4 -- arrived in Kourou on July 19. After arriving, Brasilsat underwent a check to insure that the spacecraft properly fit into the Ariane 4's payload adapter. Checks of the craft's electrical systems were performed over the weekend following July 21. Functional tests of the satellite were carried out on Monday -- the 24th -- followed by check-outs of the craft's pressurization systems on Tuesday.
Loading of the spacecraft's propellant is slated to begin on July 28.
Brasilsat B4 will operate on behalf of the Brazilian EMBRATEL telecommunications company. It is based on the Hughes Space and Communications 376W model of spacecraft and was ordered in June of 1998. It is the fourth, and possibly last, in the Brasilsat B series. All of the three previous Brasilsat B series of spacecraft have been launched on Ariane rockets. The first two EMBRATEL Brasilsat satellites began service in 1985.
Like all previous Brasilsat spacecraft, Brasilsat B4 will provide telephone, television, facsimile, data transmission, and business networking services throughout Brazil. It is designed for a lifetime of around 12.6 years.
Brasilsat B4 will be spin-stabilized, just as all 376W model spacecraft are. At the beginning of its life, it will weigh around 2,320 pounds (1052 kg).
Brasilsat B4 will feature 28 C-band transponders and will be positioned at 92 degrees West longitude in its geostationary orbit.
The other payload for this mission -- the Egyptian Nilesat 102 -- arrived at the spaceport on July 11. After being transferred to one of the satellite processing facilities, Nilesat 102 started its pre-launch check-out, similar to what its fairing-mate is undergoing. After balance checks are completed, propellant loading will commence.
Nilesat 102 and its 12 Ku-band repeaters will be positioned high above northern Africa. It will be able to transmit data to as far in the west as Morocco and as far in the east as the Arabian peninsula and the Persian Gulf. It is designed for a lifetime of around 14 years. The craft, along with Nilesat 101 already in orbit, will be able to transmit over 100 channels via the "direct-to-home" system, with antennas only 60 cm in diameter. Nilesat 102 will weigh over 3,000 pounds at the beginning of its life.
Next week, the Ariane 4 launcher will be rolled out from the main assembly bay to the launch zone at ELA-2, where it will stay until the launch. After arriving at the launch zone, the vehicle's two solid-fueled strap-on boosters will be mated onto the launcher.
Flight 131 will fly in the Ariane 44LP version of the reliable Ariane 4 rocket. The Ariane 44LP features two solid-fueled and two liquid-fueled strap-on boosters and three core stages.
Flight data file
Vehicle: Ariane 44LP
Payload: Brasilsat B4 & Nilesat 102
Launch date: Aug. 17, 2000
Launch window: 2316-2358 GMT (7:16-7:58 p.m. EDT)
Launch site: ELA-2, Kourou, French Guiana