Russian Rokot lofts another Gonets-M trio

by Chris Bergin

A Russian Rokot launch vehicle with a Briz-KM Upper Stage has launched from the Plesetsk space center in northern Russia, carrying the another trio of Gonets-M satellites with a Cosmos 2499 satellite also classed as hitching a ride. The launch took place at 13:48 UTC on Tuesday, following a delay due to issues with its first stage engine during pre-launch processing.

Launch Overview:

The Russian launch system is tailored to payloads requiring a performance of at least 1,950 kg for launches into Low Earth Orbit (LEO). The three-stage liquid fuelled rocket has dedicated launch facilities at Plesetsk Cosmodrome under the control of Eurockot.

Rokot is a fully operational, three stage, liquid propellant Russian launch vehicle which is being offered commercially by Eurockot Launch Services for launches into low earth orbit. The German-Russian joint venture company was formed specifically to offer this vehicle commercially.

The Rokot launch vehicle uses the SS-19/(RS-18) Stiletto ICBM for its first two stages.

The SS-19, which was originally developed as the Russian UR-100N ICBM series, was designed between 1964 and 1975. Over 360 SS-19 ICBMs were manufactured during the 70s and 80s. The vehicle involved in Tuesday’s launch includes hardware with a batch production date of 1989.

The Breeze-KM third stage uses a re-startable storable liquid propellant engine that has been used in many other Soviet space projects.

The booster unit – which provides the first and second stages of Rokot – is taken from existing SS-19 missiles and is accommodated within an existing transportation/launch container. The third stage – which provides the orbital capability of the launcher – is newly manufactured.

A32This upper stage contains a modern, autonomous control/guidance system which controls all three stages. The upper stage multiple engine ignition capability allows implementation of various payload injection profiles.

The Rokot second stage has an external diameter of 2.5 meters and a length of 3.9 metres. It contains a closed-cycle, turbopump-fed, fixed main engine designated RD-0235 and verniers designated RD-0236 for directional control – as listed in the 200 page vehicle overview presentation (L2).

Separation of the first and second stages is a “hot separation” – due to the fact that the vernier engines are ignited just before the separation. The exhaust gases are diverted by special hatches within the first stage.

After separation, the first stage is braked by retro rockets, then the second stage main engine is ignited. Like the first stage, it contains a common bulkhead and a hot gas pressurization system.

The Breeze-KM stage – which has now been adopted as the standard version of the third stage for the commercial version of Rokot – is a close derivative of the original Breeze-K stage flown during the first three Rokot flights.

A42It comprises three main compartments which include the propulsion compartment, the hermetically sealed equipment compartment and the interstage compartment. To allow larger satellites to be accommodated and to reduce dynamic loads, structural changes to the Breeze-K stage were introduced.

The structure of the equipment bay of the original Breeze-K stage has been widened and flattened by redistribution of the control equipment.

The Gonets-M satellites – according to the Russian Space Agency – are intended to provide digital user terminal GLONASS positioning data, as well as electronic mail services. However, this is understood to be inaccurate, with Gonets-M having no role in the GLONASS operation.

The Gonets-M satellites – of which numbers 21, 22 and 23 as part of Block 14 were launched on Tuesday – are upgraded versions of the Gonets satellites, a derivative of the military Strela-3 satellite system. They have a lifetime of five to seven years.

The satellites were delivered to the launch site in January, ahead of a launch that was set to take place in February. However, the rocket suffered an issue with its first stage engine during processing, delaying the launch until the end of March.

Post-launch reports in the Russian media also noted a fourth passenger that hitched a ride uphill, classed as a new “Cosmos 2499”.

(Images via Roscosmos).

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