Proton flies its last scheduled commercial mission
After nearly a quarter of a century competing on the international launch market, the Proton rocket lifted off on October 9, 2019, with the final pair of commercial satellites booked to fly on what used to be Russia's key space money-maker. The four-stage booster successfully delivered the Eutelsat-5 West B communications satellite and the first Mission Extension Vehicle, MEV-1, designed to extend operational life of aging satellites.
Proton launch with Eutelsat-5WB/MEV-1 at a glance:
Preparing the mission
The two-launch agreement between the European satellite operator Eutelsat and the International Launch Services, ILS, which markets Proton rockets to commercial customers, was announced on October 12, 2016. The deal also included the first order for the Proton-Medium rocket (which was never built) to carry an unidentified payload for Eutelsat in 2019 or 2020. The agreements for both launches were pre-arranged in a preliminary deal between ILS and Eutelsat, first announced in October 2015. The finalized agreement called for a Proton-M rocket to deliver the Eutelsat-5 West B communications satellite, or Eutelsat-5WB for short. Thanks to extra capacity aboard Proton, Eutelsat essentially sublet the available payload mass to the Northrop Grumman corporation to launch its first Mission Extension Vehicle, MEV-1. Not coincidently, the Eutelsat-5WB was also built by Northrop Grumman.
By July 2018, the mission had to be postponed from the fourth quarter of 2018 to March 2019, until after the launch of the Yamal-601 satellite, due to delays with the delivery of the Eutelsat and MEV satellites. Then, at the end of 2018, delays with the tests of the payload adapter required the postponement of the mission until the second quarter of 2019. At the beginning of June 2019, the RIA Novosti news agency quoted a GKNPTs Khrunichev's spokesman as saying that the company "was ready to provide the launch of Eutelsat-5WB and the MEV-1 spacecraft at the end of Summer 2019, in accordance with the customers' production and testing schedule." However, sources familiar with the real status of the payload told RussianSpaceWeb.com in the second half of June that the satellites had been projected for shipment to the launch site at the end of July, allowing the start of the launch campaign in Baikonur in early August 2019. Because of the dual payload on the mission, the Northrop Grumman team in Baikonur would need more time than the regular 25-day processing campaign at the launch site. As a result, the mission could not lift off before early September, industry sources said.
By the end of June, the Northrop Grumman was yet to finalize the arrangements for the shipment of the satellites to Baikonur, which would be delayed from the last week of July to the first week of August, in turn requiring shifting the launch date for the mission to a period after September 15. However, by the beginning of August, the launch slipped further, to at least September 30. The launch time was set at 13:26 Moscow Time.
The components of the launch vehicle for the mission, including the booster stages of the Proton-M rocket, the transfer adapter, the payload fairing and the Briz-M upper stage, were shipped to Baikonur during the night from July 21 to 22, 2019, Roskosmos announced. The train with the vehicle's components reached Baikonur on July 31.
The satellites arrived at Baikonur around August 28, 2019. According to Roskosmos, the assembly of the payload section for the mission was completed by September 21 and, on the same day, it was transferred to the vehicle assembly building, where specialists began the final integration of the Proton-M rocket. During the following campaign, the team had to integrate the payload section with the booster stages, to conduct integrated electric tests of the vehicle, to connect thermal and humidity control lines to the payload section and to put the thermal cover on the fairing. The vehicle would then be ready for a trip to the fueling pad of the Briz-M upper stage and the subsequent rollout to the launch pad.
However on September 24 ILS announced that the launch had to be delayed from September 30, due to a problem found during the electrical tests of the fully assembled launch vehicle. According to one industry source, the problem was in the flight control system of the Briz-M upper stage and it would require at least 10 days to fix. Fortunately, the issue was resolved sooner and on September 27, the launch was set for October 9.
According to Roskosmos, the State Commission overseeing the launch campaign in Baikonur convened on October 4, at 16:00 Moscow Time, and declared the rocket ready for rollout to the launch pad No. 39 at Site 200. The vehicle was scheduled to depart the processing building at 04:30 Moscow Time the next morning. On October 5, Roskosmos confirmed that the transfer of the rocket to the launch pad had been completed as scheduled.
Eutelsat-5 West B
Developed by the American company Northrop Grumman and equipped with a communications payload from European consortium Airbus Defense and Space, Eutelsat-5 West B was designed to function for 15 years.
The satellite was based on the GeoStar-2 platform developed at Orbital ATK, which later became part of Northrop Grumman. It was equipped with a Ku-band transponder payload designed to carry TV broadcast services in three service areas. With all its payloads and propellant onboard, the satellite has a mass of 2,864 kilograms.
Eutelsat planned to use this fresh addition to its fleet as a replacement for the Eutelsat-5 West A spacecraft deployed in geostationary orbit over the Equator at 5 degrees West longitude. According to the company, this orbital position is used to broadcast 300 TV channels across France, Italy and Algeria. Eutelsat also said that satellites at this orbital position play a key role in the deployment of the infrastructure across Europe and the Mediterranean basin for the distribution of Digital Terrestrial Television, DTT, signals to head-end transmitters and also is a home to the Fransat platform, which allows audience in France access to the alternative DTH service to receive French DTT channels.
Mission Extension Vehicle, MEV-1, spacecraft
Developed by Northrop Grumman, the Mission Extension Vehicle, or MEV-1, is slated to finally test the long-discussed idea of in-orbit robotic servicing of ailing satellites.
Equipped with maneuvering and docking capabilities, the MEV was designed to latch itself onto another spacecraft. The MEV can then use its propulsion, flight control and attitude control systems to maneuver and orient the old satellite, which might have expended its propellant or lost some of its capabilities before its payloads had expired. The MEV satellite was equipped with traditional liquid propellant engines and with electric propulsion thrusters giving it a wide range of maneuvering capabilities.
The docking mechanism of the MEV spacecraft allows it to link up with a spacecraft which carries no specialized rendezvous and docking hardware. According to Northrop Grumman, MEV, can use its proximity sensors and docking hardware to reliably attach itself to 80 percent of typical satellites deployed in geostationary orbit. The developer also said that after completing the work assisting the first spacecraft, the MEV vehicle could be undocked and moved multiple times during its more than 15-year operational life span to support satellites from other customers.
Northrop Grumman also advertised the MEV's availability for hosting customer's payloads with a total volume of 25 cubic meters, a mass of up to 1,000 kilograms and power consumption of 2 kilowatts.
With a mass of 2,326 kilograms, MEV was built around the GeoStar-3 satellite bus and it also inherited systems from the Cygnus cargo ship and other vehicles developed within current Northrop Grumman programs. It will be operated by SpaceLogistics, a wholly owned subsidiary of Northrop Grumman.
The MEV-1 spacecraft was scheduled to dock with the Intelsat-901 communications satellite in a "graveyard" orbit where it was boosted after the end of its operation. The MEV-1 will then push the satellite into a regular geostationary orbit where it can be used operationally for as long as five years.
Eutelsat-5 West-B/MEV-1 flight profile
Flight profile, ground track (above) and timeline (below) of the Proton launch on Oct. 9, 2019:
According to GKNPTs Khrunichev, the first, second and third stages of the Proton-M rocket were programmed to propel the payload section, including the Briz-M stage and a pair of satellites, along a standard eastward ascent trajectory from Baikonur matching an orbital inclination of 51.55 degrees toward the Equator. The payload section separated from the third stage on a suborbital trajectory 9.7 minutes after the liftoff. Around 1.6 minutes later, Briz-M fired its main engine for the first time. The maneuver, lasting 4.3 minutes, accelerated the vehicle to an orbital velocity and inserted it into a 178 by 181-kilometer parking orbit. During the next 1.6 hours, the stack coasted passively, completing a revolution around the planet.
The second Briz-M's firing, lasting 19.8 minutes, stretched the initial orbit into a highly elliptical (egg-shaped) path with a high point (apogee) of 6,007 kilometers and a low point (perigee) of 301 kilometers. The inclination was just slightly tilted to 50.4 degrees.
The space tug and its cargo then circled this intermediate orbit for the next 2.2 hours, before the Briz-M initiated its third maneuver, lasting 11.7 minutes and concluding with a 2.3-minute break to jettison the space tug's by-then-empty torus-shaped propellant tank. The main engine then re-ignited for the fourth time and fired for 6.5 minutes. The resulting dual maneuver stretched the orbit even further, boosting the apogee to the altitude of the target orbit. However, it woukd take the vehicle around 10.5 hours to reach the apogee, where Briz-M was programmed to re-ignite its engine. The fifth maneuver lasted 6.1 minutes, allowing the spacecraft to enter a so-called Super-Synchronous Transfer Orbit, or SSPO, with a perigee of 12,407 kilometers and an apogee of 65,007 kilometers. The fifth maneuver also reduced the orbital inclination of the mission to just 13.36 degrees toward the Equator.
Around 15.6 minutes after the fifth firing, Briz-M will be ready to release its dual payload. The Eutelsat-5WB satellite, located at the top of the stack, was separated first, 15 hours 34 minutes after liftoff, followed by the MEV-1 spacecraft 18.3 minutes later, completing one of the longest orbital ascent scenarios, 15 hours 54 minutes after the liftoff.
Shortly after the planned separation of the MEV-1 satellite, Northrop Grumman announced that both spacecraft launched during the mission had been operating nominally.
Slightly less than three hours after the satellites release, Briz-M will be ready for two additional maneuvers to increase its distance from its former passengers and to enable the safe opening of its onboard valves to empty its pressurized compartments. The procedure is designed to prevent a possible explosion and the resulting proliferation of space junk. The first maneuver will last 15 seconds and after a slightly longer-than-38-minute passive flight, the propulsion system will be activated again for 40 seconds. The maneuver should leave the stage in a 10,670 by 64,468-kilometer orbit.
Briz-M upper stage (bottom left) with the MEV-1 spacecraft (center) and the Eutelsat-5 WB communications satellite (top right) are being lowered into position for installation of the payload fairing in Baikonur in September 2019.
Artist rendition of the MEV spacecraft in orbit. Click to enlarge. Credit: GKNPTs Khrunichev
Artist rendition of the MEV spacecraft approaching a customer satellite. Click to enlarge. Credit: GKNPTs Khrunichev
Docking interface of the MEV-1 spacecraft. Click to enlarge. Credit: Northrop Grumman
Click to enlarge. Credit: GKNPTs Khrunichev
Eutelsat-5WB during pre-launch processing in Baikonur around Sept. 6, 2019. Click to enlarge. Credit: GKNPTs Khrunichev
MEV-1 during pre-launch processing in Baikonur around Sept. 6, 2019. Click to enlarge. Credit: GKNPTs Khrunichev
MEV-1 is being prepared for integration with the Briz-M upper stage around Sept. 18, 2019. Click to enlarge. Credit: GKNPTs Khrunichev
Briz-M, MEV-1 and Eutelsat-5WB are being covered with a payload fairing around Sept. 24, 2019. Click to enlarge. Credit: GKNPTs Khrunichev
Proton with Eutelsat-5WB and MEV-1 satellites shortly after its installation on the launch pad on Oct. 5, 2019. Click to enlarge. Credit: GKNPTs Khrunichev
Proton rocket with Eutelsat-5 West B and MEV-1 spacecraft shortly after arrival at the launch pad on October 5, 2019. Click to enlarge. Credit: Roskosmos
Click to enlarge. Credit: Roskosmos
Proton with Eutelsat-5WB and MEV-1 lifts off on October 9, 2019. Click to enlarge. Credit: Roskosmos