A Russian Government Proton-M booster, together with a Briz-M upper stage, stands ready at Baikonur Cosmodrome in Kazakhstan to launch the Raduga-1M-3 military communications satellite into orbit. Liftoff of the venerable Proton, whose heritage extends back to the mid-1960s and which will be making its 391st flight, is presently scheduled for 5:46 a.m. local time Tuesday, 12 November (6:46 p.m. EST Monday, 11 November). After a relatively smooth processing campaign, the three-stage vehicle was transferred to Launch Complex 81 at Baikonur on Friday, 8 November.
The payload for the upcoming launch has been built by Information Satellite Systems (ISS) Reshetnev Company, based within the closed city of Zheleznogorsk, close to Krasnoyarsk in Russia’s northern Krasnoyarsk Krai. Founded in 1959 under the auspices of Academician Mikhail Reshetnev, and originally known as the Applied Mechanics Science-Production Association (NPO-PM) in the Soviet era, its rich history has seen it design more than 1,000 individual satellites, including members of Russia’s GLONASS navigation network and the Ekspress geostationary communications constellation.
The Raduga (“Rainbow”) network of satellites has a long history, which extends back across three generations and almost four decades. After gaining approval from the Central Committee of the Communist Party and the Council of Soviet Ministers in April 1972, a “dummy” mission—under the cover name Cosmos 637—was launched into a 22,000-mile (35,500-km) geostationary orbit in March 1974. Less than two years later, in December 1975, Raduga-1 was placed into orbit to support the Orbita television network and provide uninterrupted, around-the-clock telephone and telegraph communications across the Soviet bloc and the Eastern Hemisphere. In addition to its outward civilian role, however, it carried a dedicated military transponder, and it was not until many years later that its secret name of “Gran” (“Edge”) was revealed.
In its earliest incarnation, the basic 4,400-pound (2,000-kg) Raduga platform featured a three-axis-stabilized attitude control system, provided by gyroscopes and microthrusters, and its solar panels independently tracked the Sun, which avoided the need to adjust the satellite’s orientation. Following Raduga-1, subsequent launches came regularly throughout the 1970s and 1980s, with only a handful of failures. A Proton-K failed during first-stage flight in December 1982, causing the loss of Raduga-12, whilst both Raduga-33 and 34 were lost during second-stage Proton failures in February 1996 and July 1999. The most recent of these losses also marked the first attempted voyage by the Briz-M upper stage, which was flying in place of the Blok-DM utilized on earlier Proton/Raduga missions.
The second generation of satellites, known as “Raduga-1,” or “Globus,” began operations with an inaugural launch in June 1989. They featured C-band transponders for enhanced communications with fixed and mobile platforms. Seven subsequent missions flew from December 1990 until February 2009, by which time the current third generation had entered service. Today’s more modern “Raduga-1M” network saw its maiden launch atop a Proton-M/Briz-M in December 2007, with a second satellite following in January 2010. These are improved Globus satellites, featuring multi-transponder transmitters, whose centimeter- and decimeter-wave capabilities enable communications with mobile stations and hard-to-reach locations, including mountainous regions. Monday night’s launch will carry the third member of the Raduga-1M system into geostationary orbit. Weighing an estimated 5,500 pounds (2,500 kg), Raduga-1M-3 carries a pair of deployable solar arrays and batteries and should remain operational for about five years.
This year, 2013, has been a troubled one for the Proton-M. Following a dramatic launch failure on 2 July seconds after liftoff—the Proton’s first mission to suffer a catastrophic malfunction during first-stage flight since the loss of Raduga-12 in December 1982—several months of corrective actions and scathing managerial and organizational changes were set in motion. In August, the Russian government formed the United Rocket and Space Corporation to consolidate the space sector, with Deputy Prime Minister Dmitri Rogozin announcing that it was “so troubled that it needs state supervision to overcome its problems.” A few weeks later, the Proton returned triumphantly to flight on 29 September, delivering the Astra 2E communications satellite into orbit, and secured its reliability credentials on 25/26 October by launching the Sirius FM-6 digital radio satellite.
All components of the Proton-M, including its three main stages and the restartable Briz-M upper stage, are fueled by a mixture of nitrogen tetroxide and unsymmetrical dimethyl hydrazine. Loading of these propellants aboard the Briz-M—whose single engine has the capacity to restart on multiple occasions and can support up to eight discrete firings to inject payloads into orbit—has already taken place, and the Russian State Commission formally granted approval for an early-morning rollout of the Proton to Launch Complex 81 at Baikonur on Friday, 8 November.
Based upon previous timelines, fueling of the Proton’s three stages should get underway about nine hours before liftoff, which is presently scheduled for 5:46 a.m. local time Tuesday, 12 November (6:46 p.m. EST Monday, 11 November). The rocket’s first stage consists of a central oxidizer tank, surrounded by six outboard fuel tanks, each fed by an RD-276 engine, and these will provide the initial impetus to boost the mission toward space. At T-5 minutes, the Briz-M upper stage will be transferred to internal power and will confirm the health of its systems. Ignition of the six RD-276 engines will commence at T-2 seconds, ramping up to 100 percent of rated performance to produce 2.3 million pounds (1.04 million kg) of thrust at the moment of liftoff.
A little over a minute into the ascent, the Proton will encounter a period of maximum aerodynamic stress (known as “Max Q”) on its flight surfaces, and the separation of the first stage is timed to occur at the two-minute point. The vehicle’s second stage will then pick up the baton, with its four engines generating a combined 540,000 pounds (244,950 kg) of propulsive yield for a little over 3.5 minutes. During this time, based on notes from the earlier Raduga-1M-1 and 1M-2 launch campaigns, the Russian Space Forces—who control and operate the satellites—will initiate tracking of the vehicle. Soon after second-stage separation, the Payload Fairing (PLF) will be jettisoned and the single-engine third stage will add a further 138,000 pounds (62,600 kg) of thrust for the next four minutes of flight. Shutdown of the third stage should occur about 10 minutes after launch, by which time the vehicle will have been establish onto a suborbital trajectory.
The turn will then come for the Briz-M, which has exhibited a mixture of success and failure since its maiden voyage. In August 2012, a premature shutdown of the Briz-M 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 is scheduled to execute five “burns” to insert Raduga-1M-3 into orbit. Assuming an on-time liftoff, the Raduga payload should be injected directly into its geostationary orbit about nine hours into the mission and should communicate with ground stations shortly thereafter.
Speaking at the time of the launch of Raduga-1M-1 in December 2007, Vladimir Popovkin, then-commander of the Russian Space Forces and until recently head of the Russian Federal Space Agency, described the satellite as providing “communications for armed forces and other enforcement agencies, as well as in the interests of social development of our country.”