Spaceflight Insider

Ekspress AM-6 satellite launches atop Proton-M

Photo Credit: NASA

The Ekspress AM-6 communications satellite was successfully launched atop a Proton-M rocket from Baikonur Cosmodrome at 11:09 a.m. EDT (1509  GMT). The satellite was built by ISS Reshetnev and will be operated by the Russian Satellite Communications Company as part of its Ekspress network which provides communications services to Russia and surrounding territories. The launch was the second successful Proton-M launch since the launch failure of a Proton-M rocket carrying the Ekspress AM-4 replacement satellite in May.

Launch operations started about 11 hours and 30 minutes before the scheduled launch time with the activation of the Briz-M upper stage for final testing. Some six hours before the launch all three stages of the Proton rocket were filled with approximately 1,371,275 lbs (622,000 kg) of hypergolic (fuels that ignite spontaneously when brought in contact with one another) propellants, a process which took about three hours.

The launch pad was re-opened after fueling was complete and the final hands-on work began including removal of protective covers and close-out of the Proton-M rocket and its Service Structure. The Service Structure was pulled back to a safe distance on hour before liftoff, a practice easily recognizable to those who monitor similar flights around the globe.

The Ekspress AM-6 is prepared for launch. Photo Credit: Roscosmos

The Ekspress AM-6 is prepared for launch. Photo Credit: Roscosmos

The automated countdown began at T-5 minutes. The propellant tanks were pressurized during the terminal countdown and the rocket transferred to internal power.

The Proton-M’s six first stage engines roared to life 2.5 seconds before liftoff, providing more than a million kilograms of thrust. The rocket followed a standard ascent profile, starting with a short vertical ascent before completing a roll maneuver to line up with its ascent trajectory.

The Proton's outboard engines, seen in this archive photo, resemble strap-on solid rocket boosters. Photo Credit: Khrunichev

The Proton’s outboard engines, seen in this archive photo, resemble strap-on solid rocket boosters. Photo Credit: Khrunichev

The rocket passed maximum dynamic pressure (Max-Q) 62 seconds after launch. The first stage engines shut down at T+1:59 and the 4 engines of the second stage ignited at the moment of stage separation to continue the Proton-M’s ascent.

The second stage engines continued to burn until T+5:27. The Proton’s third stage separated from the second stage by igniting its vernier engine before the RD-0213 main engine began its four minute burn.

The Payload fairing was jettisoned at  T+5:47 and the third stage main engine continued to burn until T+9:31. The vernier engine cutoff at T+9:42 and the Briz-M upper stage separated from the third stage three seconds later.

The Briz-M  has began a four-burn ascent profile which will deliver the Ekspress AM-6 satellite into geosynchronous orbit 9.5 hours after liftoff. After spacecraft separation the Briz-M will boost itself into a graveyard orbit above the GEO belt. Over the next several months the Ekspress AM-6 will use its electric propulsion system to maneuver itself from its initial drifting orbit to a geosynchronous orbit.

Ground track of the Ekpress AM-6 satellite. Image Credit: International Launch Services

Ground track of the Ekpress AM-6 satellite. Image Credit: International Launch Services

The Proton-M stands some 191 feet (58.2 meters) tall and is some 24 feet (7.4 meters) in diameter. It has a launch mass of some 1,571,896 lbs (713,000 kg). The rocket is capable of delivering cargo weighing 48,502 lbs (22,000 kg) to low-Earth-orbit (LEO) and payloads weighing 6 metric tons – to a Geostationary Transfer Orbit (GTO).

The Proton’s first stage is comprised of a central tank which carries nitrogen tetroxide (the oxidizer). Six propellant tanks encircle this central tank, each of them contain unsymmetrical dimethylhydrazine (the Proton’s fuel).

The Proton-M launch vehicle can trace its lineage back to the earliest days of the Space Age. Designed as a ballistic missile, the system has been used for a wide-range of missions. Photo Credit: Khrunichev

The Proton-M launch vehicle can trace its lineage back to the earliest days of the Space Age. Designed as a ballistic missile, the system has been used for a wide-range of missions. Photo Credit: Khrunichev

Each of the outboard tanks has a RD-276 rocket engine at its base. These engines provide the initial “push” that sends the rocket and its precious cargo out of Earth’s gravity well. The first stage’s six engines give the Proton-M an initial thrust of some 9,942 kiloNewtons. Each engine is some 9 feet (2.72 meters) in length and 5 feet (1.5 meters) in diameter.

If all goes according to plan, the first stage will only be in action for approximately two minutes. At this point the booster’s second stage take over. Unlike the unconventional configuration of the first stage with its protruding engine nodules, the second stage is a cylinder with its oxidizer and fuel tanks stacked in the traditional configuration. The second stage is capable of about three and a half minutes of flight.

This element of the Proton-M uses nitrogen tetroxide and unsymmetrical dimethylhydrazine as fuel.

The second stage draws its power from three RD-0210 engines along with a lone RD-0211 rocket engine (essentially an RD-0210 fit with a gas generator heat exchanger). These engines deliver an estimated 2.4 megaNewtons of thrust. Each engine (RD-210 and RD-0211) measures 8 feet (2.33 meters) in length and 5 feet (1.47 meters) in diameter.

The rocket’s third stage is the section that delivers the payload to its intended destination. Much like the rocket’s other stages, it uses nitrogen tetroxide and unsymmetrical dimethlhydrazine as fuel. It is outfitted with a RD-0213 rocket engine which grants some 583 kiloNewtons of thrust. The RD-0213 is similar in design to the RD-0210. The third stage is also equipped with an RD-0214 rocket engine that has four gimbaled nozzles to help direct both the stage and its precious cargo to its orbital position.  

The Ekspress AM-6 spacecraft is a communications satellite, one which will provide services to Russia and the surrounding region. Photo Credit: W. Grammer, NRAOAUINSF

The Ekspress AM-6 spacecraft is a communications satellite, one which will provide services to Russia and the surrounding region. Photo Credit: W. Grammer, NRAOAUINSF

 

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Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.

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