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|Proton launches Yamal-601
The first mission of the Proton rocket in 2019 successfully delivered the Yamal-601 satellite for Gazprom Space Systems, a division of the largest Russian oil and natural gas producer. The liftoff took place as scheduled on May 30, 2019, at 20:42 Moscow Time (1:42 p.m. EST).
Yamal-601 mission at a glance:
What is Yamal-601?
With an anticipated life span of 15 years, the Yamal-601 satellite was intended to replace the Yamal-202 satellite covering Russia and adjacent regions. The new spacecraft was designed to provide fixed communications and transmission services in C-band over the European part of Russia, the Middle East, Northern Africa and South-East Asia from an orbital position at 49 degrees East longitude. Yamal-601 was also expected to spur the development of communications services in Ku- and Ka-bands in the Russian market, including access to high-speed Internet. According to statements from Roskosmos published in 2019, Yamal-601 would become the most powerful satellite in the nation's orbital fleet in terms of data throughput. The project was funded through the dedicated federal program for the development of telecommunications in the Russian Federation, Roskosmos said, though most funding was apparently expected to come from non-budgetary sources.
Yamal-601 satellite at a glance*
In November 2012, then head of GKS Nikolai Sevastyanov told the Interfax-AVN news agency that Gazprom planned to announce a tender for the development of the Yamal-601 satellite at the beginning of 2013, so that the newly procured spacecraft could replace the previous-generation Yamal-202 sometimes after 2015. According to Sevastyanov, the new satellite was expected to carry communications payload operating in Ka-band, replacing satellites with C-band payloads and allowing customers on the ground to switch from receiving antennas with a diameter of around five meters to dishes as small as 1.2 meters, when using Ku-band, and 0.6-meter antenna with the Ka-band capability. At the same time, the throughput of ground stations would increase from 2 megabits per second for C-band to 5 and 20 megabits per second for Ku- and Ka-band, respectively.
The coverage provided by Yamal-601.
The tender for the development of Ymal-601 was conducted in 2013 and by December of that year, Thales Alenia Space in France was declared the winner. On Jan. 22, 2014, the International Launch Services, ILS, a US-based company that markets Proton rockets to commercial customers, announced the contract for the launch of Yamal-601 into orbit. At the time, the launch was planned in February 2016.
According to the original deal, the Yamal-601 satellite, weighing over 5,700 kilograms, would be based on Thales Alenia's flight-proven Spacebus-4000-C4 platform. The mission marked the second Russian company switching from domestic communications satellite developers to foreign suppliers. Previously, Russian Satellite Communications Company, RSCC, also gave contracts to non-Russian satellite producers.
However after the annexation of Crimea in 2014, the project was affected by US sanctions against Russia, which banned imports of electronics and other sensitive technologies into the country.
In March 2015, the Russian press reported about plans to re-write the contract for the development of the satellite in order to base the project on the Ekspress-2000 platform developed at ISS Reshetnev in Russia, while leaving the communications payload to be supplied by Thales Alenia. A similar arrangement was used during the development of the Yamal-401 satellite. However, by April 2016, Gazprom was apparently able to settle the situation with imports and returned to Thales Alenia Space as the prime contractor in the development of Yamal-601. However, by that time, its launch had slipped to 2018.
In May 2016, Gazprom announced a tender for the creditor of the project and in July of the same year, Moscow-based Sberbank was declared the winner, providing Gazprom with five lines of credit totaling 22 billion rubles ($341 million) for the development of the Yamal-601 satellite and its ground infrastructure, as well as for covering the cost of the launch and insurance.
By April 2017, the launch of Yamal-601 was reported to be delayed until the end of 2018. That launch date was confirmed in September 2017. However, only on April 3, 2019, did officials sign a preliminary acceptance certificate for the flight-ready spacecraft at Thales Alenia Space in Cannes, France.
On April 6, 2018, RIA Novosti quoted head of Gazprom KS Nikolai Sevastyanov as promising the launch in January 2019. However, by July 2018, the launch was re-scheduled for February 2019, and before the end of the year, the mission had to be postponed again, this time, until April or May 2019. In the first months of 2019, the launch was reported slipping to the beginning of June of that year but was finally settled for May 30.
Launch campaign begins
The rocket for the Yamal-601 mission was shipped by train from the manufacturing plant in Moscow to Baikonur on the evening of April 11, 2019. It reached the launch site in Kazakhstan on April 24, and the spacecraft landed in Baikonur aboard the An-124 transport aircraft on the morning of April 27.
During the second week of May, an international team of specialists conducted fit tests of the payload adapter for the Yamal-601 interfacing with its the Briz-M upper stage. According to Roskosmos, the tests confirmed mechanical and electric compatibility of the adapter and the spacecraft. Also, the high pressure tanks of the Briz-M were filled with pressurized gases.
On May 15 Roskosmos said that the Proton-M rocket for the mission had been assembled, had gone through pneumatic tests and was being prepared for electric tests. According to the State Corporation, the fueling of the Yamal-601 spacecraft was completed on May 14 and, after final electric tests, the spacecraft was delivered to the payload section assembly area, where the assembly of the upper composite started on May 17. During the operation, the satellite was connected to the payload adapter and the resulting assembly was then integrated with the upper stage, followed by electric checks. Next, the stack was covered with the two sections of the payload fairing to form the upper composite of the launch vehicle. Its final checks were completed on May 21 and the upper composite was moved to the final assembly hall at Facility 92A-50 for the integration with the booster stages of its Proton rocket.
A Proton rocket with the Yamal-601 communications satellite is loaded on its transporter inside the vehicle assembly building.
In the following few days, specialists conducted mechanical and electric integrated tests of the payload section and the launch vehicle, attached hoses for thermal control of the spacecraft under payload fairing, which would be required during the final countdown operations, and installed thermal control blankets on the payload fairing. The rocket was then loaded on its erector/transporter for a transfer to the Technical Fueling Pad, TZP, where propellant was pumped aboard the Briz upper stage. The Briz fueling operations were followed by a rollout of the rocket to the launch pad on the morning of May 27, 2019, Roskosmos said.
How Yamal-601 was launched
The launch of the Proton-M/Briz-M rocket carrying the Yamal-601 communications satellite took place as scheduled on May 30, 2019, at 20:41:59.970 Moscow Time (1:42 p.m. EDT), from Pad 39 at Site 200 in Baikonur Cosmodrome, Kazakhstan.
To deliver Yamal-601, Proton followed a launch profile typical for most commercial missions. The first, second and third stages of the launch vehicle flew an ascent trajectory matching the orbital inclination of 51.6 degrees toward the Equator. The third stage then released the payload section, including the Briz-M upper stage and the spacecraft, into a sub-orbital trajectory just short of orbital velocity. It was to ensure that the third stage falls into the ocean at a pre-determined location, rather than reaching low orbit which would decay unpredictably. Several days before launch, Russian authorities issued a warning to air traffic to avoid a remote area in the Pacific Ocean, east of Japan, where surviving debris of the third stage were expected to splash down after launch.
Upper stage operations
In a period of about nine hours following the liftoff, Briz-M was programmed to perform a total of five engine firings to boost its payload first to a circular parking orbit, then to an intermediate orbit, followed by a transfer orbit, and, finally, to a geostationary transfer orbit.
Separation of the satellite from the upper stage into a highly elliptical orbit took place 9 hours 13 minutes after liftoff at 05:55 Moscow Time on May 31, 2019 (10:55 p.m. EST on May 30).
Several minutes after the planned separation, Roskosmos confirmed the successful completion of the flight.
Yamal-601 was designed to use its own propulsion system to enter the geostationary orbit 36,000 kilometers above the Equator and take its operational position at 49 degrees East longitude.
Approximate launch timeline of the Proton rocket with the Yamal-601 satellite:
A typical ground track of the Proton launch (top) and a flight scenario featuring five engine firings of the Briz-M upper stage.
According to industry sources, Yamal-601 was released from the Briz-M upper stage into orbit well within specifications following its launch aboard the Proton rocket on May 30, 2019. However, on June 4, Gazprom space systems announced that specialists at Thales Alenia Space had found it necessary to conduct additional checks related to the operation of the apogee engine aboard the satellite, which could require to change the timeline of its transfer to the operational orbit. The company said that the issue had not involved an engine failure.
On June 6, Gazprom said that at 12:27 Moscow Time, four low-thrust engines aboard Yamal-601 initiated the first maneuver using a backup flight profile to reach the satellite's operational position in the geostationary orbit. According to the company, after multiple maneuvers of the low-thrust propulsion system, the satellite would reach its planned position at 49 degrees East longitude at the beginning of July 2019. (In its June 7 press-release, Thales Alenia said that the estimated time of arrival in the required position was expected at the end of June 2019.) According to Thales Alenia, the first orbit-raising maneuver using the backup strategy had lasted about two hours and had been successful.
Gazprom and Thales Alenia stressed that the requirement for the 15-year life span of the Yamal-601 satellite would still be achieved, even after the competition of the backup orbital insertion mode.
Gazprom also disclosed that the originally planned maneuver using the main engine aboard Yamal-601 on June 1 to boost the spacecraft from the geostationary transfer orbit, GTO, to the geostationary orbit, GSO, was interrupted due to the deviation of the satellite from the correct attitude, presumably due to shifting of the apogee engine's thrust vector. Following the aborted maneuver, the spacecraft entered a safe mode with solar orientation and all its systems continued functioned well, Gazprom said. According to the company, in order to reduce risks, specialists at Thales Alenia Space proposed the use of the backup orbital insertion mode using the low-thrust propulsion system.
Western radar data did confirm that the spacecraft had been climbing toward the geostationary altitude and reducing the tilt of its orbital plane relative to that of the Equator. By June 10, the Yamal-601 satellite was tracked in a 12,231.0 by 35,790.9-kilometer orbit with an inclination 10.2 degrees, comparing to the previous 6,740 by 35,716-kilometer orbit with an inclination 17 degrees. According to a message on the online forum of the Novosti Kosmonavtiki magazine, the satellite was expected to reach the geostationary orbit on July 9, 2019.
By June 11, the spacecraft boosted its perigee to 13,400 kilometers and reduced inclination to 9.1 degrees. On June 17, the spacecraft was in a 27,878 by 35,704-kilometer orbit with an inclination 1.779 degrees toward the Equator.
On June 24, Thales Alenia Space announced that the Launch Early Operation Phase, LEOP, had been completed and Yamal-601 had reached its nominal geostationary orbit. The payload aboard the spacecraft was then ready for In-Orbit Testing, IOT, which would conclude with the transfer of the spacecraft into service, the company said. According to Thales, Yamal-601 would operate beyond its 15-year life span defined by the contract.
A likely image of the Yamal-601 satellite during assembly. Credit: Roskosmos / Thales Alenia Space
Yamal-601 during readio tests in echoless chamber. Click to enlarge. Credit: Thales Alenia Space
Testing of the antenna deployment aboard Yamal-601 satellite. Click to enlarge. Credit: Thales Alenia Space
A photo of the Yamal-601 satellite published by Roskosmos on April 5, 2019, with the announcement about the preliminary certification of the spacecraft at Thales Alenia Space in France. Click to enlarge.
An upper composite containing Yamal-601 satellite is being prepared for integration with lower three stages of its Proton rocket. Credit: Roskosmos
Proton rocket departs for the launch pad on the morning of May 27, 2019. Click to enlarge. Credit: Roskosmos
Proton rocket with the Yamal-601 communications satellite is erected in vertical position shortly after rollout to Pad 39 at Site 200 on the morning of May 27, 2019. Click to enlarge. Credit: Roskosmos
A mobile serives tower moves into position around the Proton rocket with the Yamal-601 satellite shortly after its rollout to the launch pad on May 27, 2019. Click to enlarge. Credit: Roskosmos
Proton-M with Yamal-601 shortly before liftoff on May 30, 2019. Click to enlarge. Credit: Roskosmos
Proton-M with Yamal-601 shortly before liftoff on May 30, 2019. Click to enlarge. Credit: Roskosmos
Proton-M with Yamal-601 lifts off on May 30, 2019. Click to enlarge. Credit: Roskosmos