Proton-M launches with SIRIUS 4 – ILS Return To Flight

by Chris Bergin

International Launch Services (ILS) are back in action, following the successful launch of their Proton-M, carrying the SIRIUS 4 communications satellite, from the Baikonur cosmodrome.

Following a 9 hours, 13 minute ride on the Briz-M upper stage, SIRIUS was successfully released into the satellite into geostationary transfer.

L2 Resources: Proton Launch Vehicle Manual and Payload Planner’s Guide, plus more.


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Mission background:

The failure of the Proton launch with the JCSAT-11 satellite back in September, was caused – according to the independent Failure Review Oversight Board (FROB) – by a damaged cable, which prevented activation of the pyro bolts that were to have separated the first and second stages of the rocket.

‘We acknowledge the diligent effort from the people who enabled such a timely return to flight – the Russian State Commission; our partner, Khrunichev; our customer; the satellite manufacturer; the FROB members; and the U.S. Defense Technology Security Administration,’ said ILS President Frank McKenna.

Proton flights resumed on October 26, with a Russian federal mission to orbit three Glonass satellites.

The SIRIUS 4 satellite is a Lockheed Martin A2100AX model, will weigh approximately 4600 kg at lift-off, making it the largest in the SIRIUS fleet. SIRIUS 4 is a multi-mission Ku-and Ka-band satellite offering a wide range of communications services across Europe and Northern Africa.

The A2100 geosynchronous spacecraft series is designed to meet a wide variety of telecommunications needs including Ka-band broadband and broadcast services, fixed satellite services in C-band and Ku-band payload configurations, high-power direct broadcast services using the Ku-band frequency spectrum, and mobile satellite services using UHF, L-band and S-band payloads.

The A2100’s modular design features a major reduction in moving parts – simplifying construction, increasing on-orbit reliability, and reducing weight and cost. The A2100 bus is produced entirely from composite materials, which makes it stronger and lighter than other bus designs and reduces launch costs. The composite structure also protects the payload from thermal distortions. The design lifetime of an A2100 satellite is 15 years.

The Proton launch vehicle intended for the Sirius 4 mission consists of three stages and a space head that uses a Breeze-M upper stage. The space head also incorporates a payload fairing and an adapter. The Proton first stage consists of a central assembly containing an adapter, oxidizer tank, tail section, and six lateral assemblies. All the lateral assemblies are similar in design. Each assembly includes a fore section, fuel tank and tail section where the rocket engine is fixed.

The first stage is powered by six RD- 275 single-chamber cruise liquid propellant engines developed and manufactured by NPO Energomash. The propulsion unit develops 9,600 kN thrust at lift-off.

The second, cylinder-shaped stage includes an adapter, propellant section and tail section. The thruster facility of the second stage includes four similar sustainer liquid propellant engines: three RD-0210 engines and one RD-0211 engine – all built by KBKhA. The nose bay hosts six solid-propellant retro motors.

The rocket’s third stage is a cylinder-shaped structure that includes an equipment bay, a section of fuel and oxidizer tanks, a sustainer engine fixed on the fuel tank, and an aft bay with a steering motor inside. The aft bay accommodates four solid-propellant retro motors.

The propulsion unit of the RD- 0212 third stage consists of an RD-0213 sustainer liquid propellant engine and a four-chamber RD-0214 steering engine. In terms of design and operating principle, the sustainer engine is similar to the RD-0211 engine of the second stage: in fact, the 0213 version is a modification of RD-0211.

The Proton launch vehicle will inject the satellite into geosynchronous transfer orbit, using a four-burn Breeze M mission design.

The first three stages of the Proton will use a standard ascent trajectory to place the Breeze M fourth stage, with the satellite, into a suborbital trajectory, from which the Breeze M will place itself and the spacecraft into a circular reference, or parking, orbit of 192 km (119.3 miles), inclined at 51.5 degrees. Then the satellite will be propelled to its transfer orbit by additional burns of the Breeze M.

Following separation from the Breeze M, the spacecraft will perform a series of liquid apogee engine burns to raise perigee, lower inclination and circularize the orbit at the geostationary altitude of 35,786 km (22,236 miles).

Full mission background is available on the live event page – linked above.

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