Barely a month after it arrived at the Baikonur Cosmodrome in Kazakhstan, Russia’s Ekspress AM4R communications satellite was launched tonight atop the three-stage Proton-M booster with a Briz-M upper stage. Launch occurred precisely on time at 3:42 a.m. local time Friday, 16 May (5:42 p.m. EDT Thursday, 15 May), from Site 200/39, turning night into day across the darkened Kazakh steppe. However, as noted by NASASpaceflight.com and by Spaceflight101.com, an anomaly apparently occurred during third-stage flight. Upon arrival in its 22,300-mile (35,000-km) operational orbit, about nine hours and 13 minutes after launch, Ekspress AM4R was expected to provide television broadcasting, broadband internet, multimedia, and mobile communications services across Russia and the broader Commonwealth of Independent States (CIS). Ironically, it was intended to replace the Ekspress AM4 satellite, which was delivered into a lower-than-planned and useless orbit by a Proton-M/Briz-M malfunction in August 2011. At the time of writing, there was no official confirmation of whether the Ekspress AM4R mission is lost.
Tonight’s mission was the fourth Proton-M flight of 2014, coming hard on the heels of three geostationary communications satellite payloads: Türksat 4A in February, Ekspress AT1 and AT2 in March, and Luch-5V and KazSat-3 on 28 April. Commercial flights from Baikonur are operated by International Launch Services (ILS)—a joint U.S.-Russian company, headquartered in Reston, Va.—whilst national and military flights, like tonight’s mission, are conducted under the auspices of the Russian Government. The booster arrived at Baikonur on 28 February, followed by the Briz-M upper stage on 10 March, and the Ekspress AM4R payload was delivered in mid-April. Earlier this month, the satellite was installed atop the Briz-M upper stage, which was tasked with lifting it to geostationary altitude.
The launch of Ekspress AM4R is the 397th flight of the Proton vehicle, including commercial and Russian and former Soviet-era missions, which can trace its heritage back to the mid-1960s. Built by Russia’s Khrunichev Research and State Production Centre, it has one of the most reliable track records of any rocket in the world, although its reputation was tarnished in July 2013 by a failure, seconds after liftoff, and now by tonight’s mission failure.
The majestic 190-foot-tall (58-meter) vehicle was transferred to Baikonur’s Site 200/39—the very same pad from which another Proton-M failed spectacularly last summer—on Tuesday, 13 May, ahead of its Thursday opening launch attempt, which proceeded crisply and without incident. Earlier today, fueling of the rocket’s three stages with a mixture of nitrogen tetroxide and unsymmetrical dimethyl hydrazine got underway. The first stage consisted of a central oxidizer tank, surrounded by six outboard fuel tanks, which each fed an RD-276 engine and provided the initial impulse to boost the Proton-M and its Ekspress AM4R payload toward orbit. At 2:30 a.m. local time Thursday (4:30 p.m. EDT Wednesday), the servicing tower around the vehicle was retracted, exposing the Proton-M in all its glory and magnificence. It was at about the same time that the final personnel were cleared from the pad area. Thirty minutes later, the launch abort systems were armed. It would be their task to destroy the vehicle in the event of a major, off-nominal event during ascent.
At T-5 minutes, the Briz-M upper stage, which was charged with delivering Ekspress AM4R into geosynchronous orbit, 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 six first-stage engines got underway at T-2.5 seconds, building up firstly to 40 percent of rated performance, then hitting full 100 percent power—about 2.3 million pounds (1.04 million kg) of thrust—within two seconds and achieving a blazing liftoff into the darkened Baikonur sky at precisely 3:42 a.m. local time Friday (5:42 p.m. EDT Thursday).
Shortly after clearing the tower and rising vertically for several seconds, the Proton-M executed a computer-commanded roll maneuver to establish itself onto the proper flight azimuth to place Ekspress AM4R into orbit. A little over a minute into the ascent, the vehicle encountered a period of maximum aerodynamic turbulence (known as “Max Q”) on its airframe. The first stage was exhausted of propellant and jettisoned, as planned, about two minutes into the flight, by which time the four engines of the second stage had 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 separation, at T+5 minutes and 47 seconds, the Payload Fairing (PLF) was jettisoned and the single engine of the Proton-M’s third stage was expected to add a further 138,000 pounds (62,600 kg) of thrust for the following four minutes. It was expected to finally shut down about 9.5 minutes after leaving Baikonur, by which time the vehicle should have established itself onto a suborbital trajectory. It would then coast for 90 seconds, before the first of five “burns” by the Briz-M was due to get underway at 3:53 a.m. local Kazakh time Friday (5:53 p.m. EDT Thursday), some 11 minutes and 16 seconds into the flight. The first burn was scheduled to last 4.5 minutes and was to be followed by a pre-planned phase of extended coasting.
The Briz-M has exhibited a mixture of success and failure since its maiden voyage. Two years ago, 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. However, in March 2013, a Proton-M/Briz-M successfully injected Mexico’s Satmex-8 communications satellite into orbit and several other successful missions have followed. Capable of restarting up to eight times in flight, the Briz-M has a battery-powered lifetime of 24 hours and was supposed to support five discrete burns to insert Ekspress AM4R into orbit. These were scheduled to last 4.5 minutes, 18 minutes, 12 minutes, five minutes, and seven minutes, with the final burn expected to terminate at precisely nine hours after launch from Baikonur. Thirteen minutes later, at T+9 hours and 13 minutes, Ekspress AM4R should have separated from the Briz-M into geostationary transfer orbit, inclined 20.5 degrees to the equator. This was to be followed by a “disposal” burn by the Briz-M to remove itself from the vicinity of the satellite and position itself appropriately for de-orbit.
Ekspress AM4R has been built by EADS Astrium on behalf of the Russian Satellite Communications Company and is a member of Russia’s most powerful next generation of geostationary communications satellites. It represents the latest in a long history of Ekspress missions, dating back to Ekspress 1 in 1994, which has steadily modernized Russia’s communications satellite network since 2005. Weighing 12,730 pounds (5,775 kg), it is equipped with 63 C-band, Ku-band, Ka-band, and L-band transponders and 10 antennas to cover the territory of Russia and its former satellite republics, the Commonwealth of Independent States (CIS).
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