Proton-M launches with KA-SAT for speedy return to flight

by Chris Bergin

International Launch Services (ILS) have launched their Proton-M rocket on Sunday, on a mission which is marking the quick return to flight for the Russian workhorse which suffered from a failure during a recent government launch. Launched at 21:51 GMT from the Baikonur Cosmodrome in Kazakhstan, the Proton deployed the KA-SAT communications satellite for Eutelsat, after what was nine hours of flight.

Proton Launch:

The Proton booster is 4.1 m (13.5 ft) in diameter along its second and third stages, with a first stage diameter of 7.4 m (24.3 ft). Overall height of the three stages of the Proton booster is 42.3 m (138.8 ft).

The first stage consists of a central tank containing the oxidizer surrounded by six outboard fuel tanks. Each fuel tank also carries one of the six RD-276 engines that provide first stage power. Total first stage vacuum-rated level thrust is 11.0 MN (2,500,000 lbf).

Of conventional cylindrical design, the second stage is powered by three RD-0210 engines plus one RD-0211 engine and develops a vacuum thrust of 2.4 MN (540,000 lbf).

Powered by one RD-0213 engine, the third stage develops thrust of 583 kN (131,000 lbf), and a four-nozzle vernier engine that produces thrust of 31 kN (7,000 lbf). Guidance, navigation, and control of the Proton M during operation of the first three stages is carried out by a triple redundant closed-loop digital avionics system mounted in the Proton’s third stage.

The Breeze-M upper stage is the Phase III variant, a recent upgrade which utilizes two new high-pressure tanks (80 liters) to replace six smaller tanks, along with the relocation of command instruments towards the centre – in order to mitigate shock loads when the additional propellant tank is being jettisoned.

The Proton M launch vehicle, utilizing a 5-burn Breeze M mission design, lifted off from Pad 39 at Baikonur Cosmodrome, Kazakhstan, with the KA-SAT satellite on board. The first three stages of the Proton used a standard ascent profile to place the orbital unit (Breeze M upper stage and the KA-SAT satellite) into a sub-orbital trajectory.

From this point in the mission, the Breeze M performed planned mission maneuvers to advance the orbital unit first to a circular parking orbit, then to an intermediate orbit, followed by a transfer orbit, and finally to a geosynchronous transfer orbit. Separation of the KA-SAT satellite came approximately 9 hours, 12 minutes after liftoff.

Eutelsat’s KA-SAT is a new genera­tion of High Throughput Satellites optimized for consumer broadband services and targeting users located beyond range of high-speed terrestrial networks. Fully-operating in Ka-band frequencies and with total throughout of 70 Gigabits per second.

Through a configuration of 82 spotbeams and a ground infrastructure of ten gateways connected to the Internet, service will be provided across Europe and the Mediterranean Basin. In addition to supporting expansion of Eutelsat’s Tooway consumer broadband service, KA-SAT will open new resources for telecom operators, broadcasters and ISPs, for data and video services.

Based on the EuroStar E3000 platform, the 6,150 lb KA-SAT will have an anticipated service life of over 15 years from its orbital location at 9 degrees East.

The launch was the 12th Proton launch in 2010, the 363rt overall. It was also be the 64th ILS Proton launch, the 8th ILS Proton launch in 2010. The mission was also the sixth Eutelsat launched on a Proton.

Failure Investigation:

Sunday’s launch follows an investigation into the December 5 failure of the Russian Federal mission which was utilizing a Proton M Block DM-03 vehicle, resulting in the loss of three GLONASS-M navigation satellites.

A Russian State Commission was established to determine the cause of the failure and to establish corrective actions, which resulted in ILS having to hold their K-SAT mission until an interim report was made available.

While the Proton M is a flight-proven configuration, the government launch was the maiden flight of the Block DM-03 upper stage, which is a derivative of Energia’s Block DM-3 used on the ILS Protons.

According to the preliminary State Commission report, dated 10 December, the three lower Proton M stages performed nominally, with the DM-03 handed the blame for the failure. The report also stated that there were “no issues with the functioning of LV systems and assemblies that have been detected. The trajectory parameters calculated by the LV motion control system conform to the trajectory measurements obtained from external sources.

“Command generation times of the flight timeline correspond to estimated values. The LV motion control system was found to have been functioning nominally, in line with the preset algorithms.”

With the root cause related to an error in the DM-03 documentation, resulting in up to two tonnes of additional LOX being loaded into the Upper Stage, making it too heavy, all elements of ILS’ vehicle were cleared for flight, with the launch date only delayed by a week.

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