Proton launches Ekspress-AM5 communications satellite
A Proton rocket concluded its operations in 2013 with a successful mission to deliver the most advanced Russian communications satellite Thursday. The 3,400-kilogram Ekspress-AM5 is the first spacecraft based on ISS Reshetnev's Ekspress-2000 platform, the company's brand-new and largest standard spacecraft to date.
On Aug. 12, 2009, ISS Reshetnev reached an agreement with Russian Satellite Communications Company, GPKS, to develop a pair of new-generation communications satellites, Ekspress-AM5 and Ekspress-AM6. The 3,400-kilogram Ekspress-AM5 would be the first spacecraft based on ISS Reshetnev's Ekspress-2000 platform, the company's largest standard bus. According to ISS Reshetnev, Ekspress-2000 could accommodate 10 antennas and 84 transponders. The 1,070-kilogram communications payload onboard Ekspress-AM5 included C-band, Ku-band, L-band transponders and, for the first time in the Russian practice, Ka-band transponders. The Canadian company, MDA, won a contract to build transponders and antennas for the spacecraft.
The satellite will provide a broad range of digital communications and broadcast services, including government communications.
The onboard power supply system featuring for the first time five-section solar panels with a total area of 84 square meters and a span of more than 33 meters, was designed to provide at least 12.1 kilowatts of electricity to the payload and a total power output of 15 kilowatts.
Ekspress-AM5 and AM6 were also equipped with four electric engines, SPD-100V, using 300 kilograms of xenon gas as a propellant to insert these satellites into their final orbits three or four months after launch. The new propulsion system helped to resolve the payload limitations of the Proton rocket providing a total of 150 kilograms in mass savings.
The spacecraft was to be positioned at 140 degrees East longitude over the Equator and have a life span of 15 years. The satellite was ensured for 7.08 billion rubles.
The satellite is 7.723 millimeters tall.
The agreement for the launch of Ekspress-AM5 was reached on Oct. 27, 2009, aiming the first quarter of 2012. The mission then slipped to December 2012 and by September of that year it was expected in the second quarter of 2013. At the beginning of 2013, the mission slipped to August. In October, the mission was officially scheduled for Dec. 26-28, 2013, however there were reports that ISS Reshetnev would have to postpone the delivery until 2014. Still, on November 18, Ekspress-AM5 arrived to Baikonur. The Briz-M upper stage for the mission followed on November 26.
Proton lifts off with Ekspress-AM5 on Dec. 26, 2013. Credit: Roskosmos
The launch of the Proton-M rocket with a Briz-M upper stage from Pad 24 at Site 81 in Baikonur Cosmodrome took place as scheduled on Dec. 26, 2013, at 14:49:56 Moscow Time (5:49 a.m. EST). The vehicle is carrying the Ekspress-AM5 communications satellite for Russian Satellite Communications Company, GPKS. According to the Russian space agency, Roskosmos, a payload section successfully separated from the third stage of the launch vehicle at 14:59 Moscow Time.
According to the flight plan, the first, second and third stages of the Proton rocket fired for a total of 580 seconds, sending the payload section, including the Briz-M upper stage and the satellite, into a suborbital ballistic trajectory. Then, the first engine firing of the Briz-M upper stage inserted the stuck into an initial parking orbit with an altitude of around 180 kilometers and an inclination 51.5 degrees toward the Equator. The Briz-M then fired its engine again to reach an elliptical orbit with an apogee of 6,000 kilometers.
Upon reaching an apogee, Briz fired for the third time then jettisoned its external propellant tank and fired for the fourth time to enter the super-synchronous orbit. The separation of the satellite from the upper stage took place 9.5 hours after the liftoff at 00:12 Moscow Time on Dec. 27, 2013, (3:12 p.m. EST on Dec. 26).
On Dec. 27, 2013, ISS Reshetnev announced that Ekspress-AM5 had established communictions with ground control, all systems onboard the satellite had been working well, it had deployed solar panels and oriented itself toward the Sun.
The satellite will be activated in the next 3-5 days and its onboard electric engines will be used to adjust apogee and perigee, as well as to push the satellite toward its operational geostationary position, which will be achieved around March 20, 2014. The satellite will then undergo testing, which is scheduled to last until middle of May 2014.
In early June 2023, Ekspress-AM5 was reported experiencing technical problems, resulting in the deactivation of its Ku-band transponder, which forced some users of the satellite to seek alternative communications channels. According to a statement from the satellite's operator, the Kosmicheskaya Svayz company, GPKS, published on June 5, part of the payload aboard Ekspress-AM5 was deactivated due to a failure of the liquid thermal control loop aboard the spacecraft at 04:30 Moscow Time on June 3, 2023, and leading to the onboard temperatures exceeding operational thresholds.
In cooperation with specialists from the satellite developer, ISS Reshetnev, engineers from GPKS took actions aimed to prevent overheating of the satellite and preserving its operational capability, the company said. These steps included deactivation of some of the transponders aboard the spacecraft. According to GPKS, some users continued receiving communications services via Ekspress-AM5, while others were either in the process of transition or had already switched to available channels aboard the Ekspress-AMU7 and Ekspress-AMU3 satellites.
The situation resembled a previous incident with the Ekspress-AM6 satellite, which suffered a thermal control problem in 2020, resulting in the loss of communications capacity. Both satellites were based on ISS Reshetnev's Ekspress-2000 platform, thus raising concerns that the service modules on the AM5 and AM6 models could have a common design flaw in their thermal control system.
The latest impact on Russian satellite communications capacity came at a time when the established production model for the Ekspress satellite family, relying on Western suppliers, had been disrupted by the Kremlin's escalation of the war against Ukraine in 2022, likely resulting in severe delays if not a complete stop in the development of this type of spacecraft in Russia.
A scale model of the Ekspress-2000 satellite bus. Copyright © 2010 Anatoly Zak
An assembly of the Ekspress-AM5 satellite. Credit: ISS Reshetnev
Integration of the Ekspress-AM5 satellite with a Briz-M upper stage. Credit: GKNPTs Khrunichev
A Proton with Ekspress -AM5 satellite lifts off on Dec. 26, 2013: Click to enlarge. GKNPTs Khrunichev