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Proton successfully delivers Turksat-4B
Proton lifts off with Turksat-4B on Oct. 16, 2015.
Turksat-4B launch profile
During the delivery of the Turksat-4B satellite, Proton-M followed a typical launch profile for most commercial missions with only seconds in variation from the ascent timeline during the launch of the Turksat-4A satellite on Feb. 16, 2014.
The first, second and third stages of the launch vehicle used a standard ascent trajectory matching the orbital inclination of 51.5 degrees toward the Equator, to place the payload section including a Briz-M upper stage and the Turksat-4A satellite into a sub-orbital trajectory. According to the Russian space agency, Roskosmos, the ascent to the initial parking orbit went as planned.
According to the flight telemetry received from the Briz-M stage, it entered a suborbital trajectory, which was practically on target:
Briz-M was scheduled to perform five engine firings to advance the orbital unit first to a circular parking orbit, then to an intermediate orbit, followed by a transfer orbit, and, finally, to a geostationary transfer orbit.
Following the first firing of the Briz-M stage, telemetry from the mission confirmed that the payload section had been in good parking orbit:
The second Briz-M firing was also successful, raising an apogee and delivering the stack into the following transfer orbit:
Three hours eight minutes into the mission, Briz-M began a dual engine firing separated by the jettisoning of the external tank, which raised the apogee of the orbit to an almost geostationary altitude:
Separation of the Turksat-4A satellite took place approximately 9 hours, 13 minutes after liftoff into a highly elliptical orbit:
The satellite is expected to use its own propulsion system to enter a geostationary orbit 36,000 kilometers above the Equator.
Around two hours after the release of the satellite, the Briz-M stage was scheduled to conduct first of two additional maneuvers with its auxiliary thrusters to enter a disposal orbit. Only the first firing was confirmed with the available telemetry.
The Turksat-4B satellite was developed by Mitsubishi Electric Corporation, MELCO, of Tokyo, Japan, based on the company's standard DS2000 communications platform, which originally developed for DRTS and ETS-8 satellites under a contract with Japan's Aerospace Agency, JAXA. The typical satellite based on the DS2000 platform has a mass of around five tons, carry up to 70 transponders and produce up to 15 kilowatts of electric power with a pair of its solar panels. The electricity can be stored in nickel-hydrogen, NiH2, and lithium-ion, Li-Ion, batteries.
Besides Proton, the satellites based on DS2000 platform can be adapted for launch on Japanese H-2, European Ariane-5, American Atlas-5 and Russian-Ukrainian Zenit-3SL rockets.
Like many of its counterparts, DS2000 architecture split between the payload module carrying the communications transponders and the service module with all the support systems. A cylinder made of carbon-based plastic serves as a structural backbone of the satellite. A series of honeycomb panels carrying various systems clustered around the central tube.
The service module carries the propulsion system consisting of the main apogee engine and small attitude-control thrusters both burning hypergolic propellants. An additional ion propulsion system is also available. The three-axis attitude control system also includes reaction wheels.
The mass of the Turksat-5B satellite was originally estimated at 3,800 kilograms, however by 2015, GKNPTs Khrunichev quoted 4,924 kilograms for the spacecraft.
During its projected 15-year design life, the satellite will provide telecommunication and direct TV broadcasting services throughout Turkey, as well as in Europe, Central Asia, the Middle East and Africa. Turksat-4B will be operated at 50 degrees east position.
The satellite consists of several band transponders with expected on-orbit maneuver life of 30 years. It is designed to expand the space capacity of Turkey and provide enhanced performance to its coverage areas. The satellite will provide high flexibility of switchability and connectivity among different service areas to its customers, according to the manufacturer.
*4,928 kilograms, according to GKNPTs Khrunichev
The agreement for the launch of Turksat-4B was announced on April 5, 2011. In February 2014, the launch was planned in November of the same year. By December 2014, the mission was postponed until June 2015, but that launch date could not be maintained due to the Proton rocket failure with MexSat-1 satellite on May 16, 2015. By the time the Proton successfully returned to flight in August 2015, the launch of Turksat-4B was expected in October. As of mid-September, the mission was scheduled for October 13. The satellite was delivered to Baikonur on September 2, followed by the Briz-M upper stage on September 16. The assembly of the first, second and third stages of the rocket was completed in Baikonur on September 18 followed by integrated tests of the launch vehicle. In parallel, a Japanese team of the satellite manufacturer was conducting the fueling of Turksat-4B, GKNPTs Khrunichev announced. According to the company, the final assembly of the payload section started on September 30.
However, at the beginning of October, an overhead crane, which was needed to place the fully assembled payload section onto its transporter, failed, requiring from one to few days for its repair and re-certification for further operations. As a result, the launch of Turksat-4B was postponed from October 13, 2015, at 23:45 Moscow Time to October 16, 2015, at 23:40 Moscow Time (4:40 p.m. EDT). According to sources in Baikonur, a controller on the crane failed and had to be replaced. Peculiarly, during the Inmarsat-5 F3 launch campaign earlier this year, a processing team working at the Proton facility experienced problems with one of two cranes, which would not come to a smooth stop when running along the length of Building 92A-50. Fortunately at the time, the problem was not serious enough to stop operations.
The fully assembled launch vehicle arrived at a fueling station, where on October 11 and October 12, the Briz-M upper stage was loaded with propellants, followed by the arrival to Pad 39 at Site 200 on October 13, 2015.
A Proton rocket with the Turksat-4B satellite shortly after its rollout to the launch pad in Baikonur on Oct. 13, 2015.
Read (and see) much more on the history of the Russian space program in a richly illustrated, large-format glossy edition:
Artist renderings of the Turksat-4B satellite. In reality, the satellite would be deployed in much higher orbit and would not perform formation flying. Credit: ILS, MELCO
The DS2000 platform. Credit: MELCO
On the night from October 7 to October 8, 2015, when the preparations for the launch of Turksat-5B were entering the final stage, a fire broke out in the East end section of the residential area of Baikonur. The blaze reportedly originated at a night club next to the Asian market on Gagarin Blvd., local sources said. The Russian Ministry of Emergency Situations, MChS, was quoted as saying that it took until morning on October 8 to extinguish the fire, which had damaged a popular shopping center.
Proton with Turksat-4B arrives at the launch pad on Oct. 13, 2015. Click to enlarge. Credit: Roskosmos
Turksat-4B shortly before liftoff on Oct. 16, 2015. Click to enlarge. Credit: Roskosmos
Turksat-4B lifts off on Oct. 16, 2015. Click to enlarge. Credit: Roskosmos