Türksat 4A Reaches Geostationary Orbit After Flawless Proton-M Launch

Last night's Proton-M launch with Türksat 4A was the 85th mission conducted by ILS and its first major passenger for Turkey. Photo Credit: ILS, with thanks to Mike Barrett

Last night’s Proton-M launch with Türksat 4A was the 85th mission conducted by ILS and its first major passenger for Turkey. Photo Credit: ILS, with thanks to Mike Barrett

International Launch Services (ILS)—the joint U.S.-Russian company, headquartered in Reston, Va., which operates all commercial Proton-M rockets out of Baikonur Cosmodrome, Kazakhstan—has successfully delivered its first major Turkish passenger into orbit, by inserting the Türksat 4A communications satellite into a 22,300-mile (35,000-km) geostationary transfer orbit. Following a flawless launch from Baikonur’s Site 81/24 at 3:09:00 a.m. local time Saturday (4:09:00 p.m. EST Friday), the three-stage Proton-M and its restartable Briz-M upper stage supported the satellite’s climb to orbit, and Türksat 4A was released into space, precisely on time, at T+9 hours and 12 minutes.

Last night’s flight was the first Proton-M mission by ILS in 2014 and the 85th in total to have been conducted under the company’s auspices. However, the Proton rocket family is an old one, with a heritage dating back to the mid-1960s, and this represented its 394th launch overall, including commercial and Russian and former Soviet Union missions. The 190-foot-tall (58-meter) rocket was transferred to Site 81/24 on Tuesday, ahead of its Friday night opening launch attempt, which proceeded crisply and without incident. Partly cloudy and freezing conditions at the launch site—which dropped to about -12 degrees Celsius (10.4 degrees Fahrenheit) in the vicinity of the pad—proved no obstacle for the formidable Proton, as it chugged smoothly through its propellant loading process.

Earlier in the day, the fueling of the rocket’s three stages with a mixture of nitrogen tetroxide and unsymmetrical dimethyl hydrazine commenced. The first stage, consisting of a central oxidizer tank, surrounded by six outboard fuel tanks, fed an RD-276 engine, which provided the initial impetus to boost the Proton-M and its Türksat 4A payload toward orbit. At 2:18 a.m. local time Saturday (3:18 p.m. EST Friday), with a little less than an hour to go, the service structure was retracted from the vehicle and the final personnel were cleared from the pad. Although it was slightly breezy at Baikonur, the upper-level winds were deemed acceptable and posed no constraints to launch.

The Proton-M and its Türksat 4A primary payload are pictured at the Mobile Service Tower, backdropped by the early glimmers of dawn at Baikonur Cosmodrome. Photo Credit: ILS

The Proton-M and its Türksat 4A primary payload are pictured at the Mobile Service Tower, backdropped by the early glimmers of dawn at Baikonur Cosmodrome. Photo Credit: ILS

At T-5 minutes, the Briz-M was transferred to internal battery power and confirmed that its myriad systems were healthy. In the final phase of the countdown, the Proton-M pressurized its propellant tanks and the “Launch Vehicle Ready” signal was issued at T-1 minute and 53 seconds. Ignition of the vehicle’s six first-stage engines got underway at T-2.5 seconds, building up firstly to 40 percent of rated performance, then hitting full power—about 2.3 million pounds (1.04 million kg) of thrust—within two seconds and achieving a blazing liftoff into the darkened sky at precisely 3:09:00 a.m. local time Saturday (4:09:00 p.m. EST Friday).

Shortly after clearing the tower and rising vertically for several seconds, the Proton-M executed a computer-commanded roll maneuver to inject itself onto the proper 61.3-degree flight azimith necessary to place Türksat 4A into geostationary transfer orbit. A little over a minute into the ascent, the vehicle encountered a period of maximum aerodynamic stress (known as “Max Q”) on its airframe. The first stage was exhausted of propellant and jettisoned, as planned, about two minutes into flight, after which the four engines of the second stage picked up the baton, generating a combined 540,000 pounds (244,950 kg) of propulsive yield for the next 3.5 minutes of ascent.

Soon after second-stage exhaustion and separation, the Payload Fairing (PLF) was jettisoned and the single engine of the third stage added a further 138,000 pounds (62,600 kg) of thrust for the next four minutes of flight. Shutdown of the third stage occurred about 10 minutes after launch, by which time the vehicle had established itself onto a suborbital trajectory. It then coasted for 90 seconds, before the first of five “burns” by the Briz-M got underway at 3:20 a.m. local Baikonur time Saturday (4:20 p.m. EST Friday). The burn lasted 4.5 minutes and was followed by a pre-planned phase of extended coasting.

The Briz-M has exhibited a mixture of success and failure since its maiden voyage. In August 2012, a premature shutdown of the upper stage left Indonesia’s Telkom-3 and Russia’s Ekspress-MD2 satellites in useless orbits, and in December 2012 another launch glitch impacted the Yamal-402 satellite. Last March, a Proton-M/Briz-M successfully injected Mexico’s Satmex-8 communications satellite into orbit, and on 29 September another vehicle lofted Astra 2E. Capable of restarting up to eight times in flight, the Briz-M has a battery-powered lifetime of 24 hours and supported five discrete “burns” to insert Türksat 4A into orbit. Spacecraft separation was announced as having occurred, on time, at 12:21 p.m. local Baikonur time (1:21 a.m. EST) Saturday, at T+9 hours and 12 minutes.

At the moment of liftoff, the six RD-276 engines produced a combined 2.3 million pounds (1.04 million kg) of thrust to power the Proton-M uphill for its first two minutes of flight. Photo Credit: ILS, with thanks to Mike Barrett

At the moment of liftoff, the six RD-276 engines produced a combined 2.3 million pounds (1.04 million kg) of thrust to power the Proton-M uphill for its first two minutes of flight. Photo Credit: ILS, with thanks to Mike Barrett

This latest launch has now established the satellite into orbit on behalf of Türksat Satellite Communications and Cable TV Operations Company, based in Gölbaşı, within Turkey’s Ankara Province. It was the first time that Türksat has contracted with ILS for launch services. A second payload, Türksat 4B, is scheduled to ride another ILS Proton-M later in 2014. Built by Mitsubishi Electric (MELCO) at its Kamakura plant in Tokyo, Türksat 4A and 4B are being situated at 42 degrees East and 50 degrees East longitude respectively. They will offer communications services and direct television broadcasts across a broad region, from Central Asia, across the Middle East and Africa and Europe, and as far as eastern England. The satellites have a high flexibility of switchability and connectivity among different service areas to its customers.

Contracts with ILS to launch the two 8,380-pound (3,800-kg) satellites were signed in April 2011. Speaking at the time, Hiroyuki Inahata, head of MELCO’s space systems division, remarked that the choice of ILS was made “based on their track record of reliability, precision, launch tempo and experience.” Early last month, during an official visit to Japan by Turkish Prime Minister Recep Tayyip Erdoğan, the Türksat 4A payload was formally handed over by Mitsubishi Electric to Turkish officials.

Built by Russia’s Khrunichev Research and State Production Centre, this was the 393rd mission by a member of the Proton rocket family, which traces its heritage back to the mid-1960s, and has one of the most reliable track records of any rocket in the world. However, last year proved troubled when it suffered a dramatic and highly embarrassing launch failure on 2 July, seconds after liftoff. It was the Proton’s first catastrophic malfunction during first-stage flight in over 30 years and prompted several months of corrective actions and cutting managerial and organizational changes. A few weeks later, the Proton returned triumphantly to flight on 29 September, delivering the Astra 2E communications satellite into orbit, and restored its reliability credentials on 25/26 October by launching Sirius FM-6 and on 12 November by launching Raduga-1M-3. Most recently, on 8 December, it flawlessly delivered Inmarsat 5-F1 into orbit.

 

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