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SL-22 Soyuz-Ikar Launch Vehicle

Soyuz-U The most recent versions of the Soyuz family are the SL-22, Soyuz/Ikar and the SL-26, Soyuz/Fregat. These boosters were modified from the original Soyuz by the addition of a new upper stage, either the Ikar or the Fregat. Both boosters are a commercial venture between France and Russia to perform commercial launches with versions of the SL-4 Soyuz. Depending on the satellite payload requirements, different upper stages may be used or special purpose built.

The Ikar Upper Stage is part of the Soyuz launch system upgrade program. Built by TsSKB in Samara, this upper stage is derived from an existing flight-proven module that has been used successfully more than 30 times. Equipment and subsystems from the module are used to the maximum extent in the Ikar stage to limit new development. Modifications are limited primarily to command/control equipment and certain mechanical/electrical interfaces with the payload.

Ikar has a mass of 820 kg and is located under the Soyuz launcher's payload fairing. With an in-flight restart capability of up to 30 times, it can handle deployment of multi-satellite payloads to different orbits. A KBKhM 17D61 engine with a vacuum thrust of 2,943 kN powers the stage. It operates on UDMH/N2O4 propellant and has 16 vernier engines for flight control.

The simplest upper stage version, Ikar, is derived from the Kometa platforms used on more than twenty flights for Russian satellite programs. The GlobalStar consortium, a vast satellite constellation, has called on Starsem's services to launch 24 satellites using 6 Soyuz-Ikar. Ikar is derived from an existing, flight-proven module that had been flown successfully more than 30 times. The re-ignitable upper stage was developed from the Kometa satellite bus that performs orbit altitude changes for Earth imaging satellites.

"Ikar" Injection Module is intended for payload transfer from injection orbit to the final orbit and satellite deployment in a specific sequence and directions with determined orientation accuracy and attitude control. "Ikar" injection module can be used for enhancement of Soyuz-U, Soyuz-FG. After separation from launch vehicle "Ikar" Injection Module allows to deliver payload mass from 750 to 3920 kg to the circular and elliptical final orbits at 250-1400 km altitude with inclinations of i=51.8º (Baikonur cosmodrome) and i=62.8º; i=67.1º; i=81.4º; i=90º (Plesetsk cosmodrome).

Ikar "Ikar" Injection Module particular feature is its long autonomous operation during the orbital flight. During the orbital flight final orbit parameters for the payload are formed and satellite separation in a specific sequence and in a specific direction is achieved. "Ikar" Injection Module can be deployed by the preset yaw for satellite separation in a specific direction. At the time of satellite separation "Ikar" Injection Module provides specified orientation accuracy and attitude control accuracy.

"Ikar" Injection Module provides satellites with a fixed number of control commands, pyrotechnic commands, telemetry channels and through circuits, gives an opportunity of providing complementary satellite power supply from launch to separation from the Injection Module. High reliability of Injection Module on-board systems is achieved owing to functional redundancy and control algorithms, diagnostics and reserves management during the process of accomplishing functional tasks.

"Ikar" Injection Module integrated propulsion system is intended for multiple (up to 50 times) actuations. The concept of maximum borrowing of structural and hardware base of instrument and accessories bay of base product, which has justified itself during the process of long-term operation is taken as a basis for "Ikar" Injection Module development. "Ikar" Injection Module represents a single module, consisting of unpressurized accessories bay and pressurized instrument bay, fixed on it, with adapter for payload mounting. "Ikar" Injection Module integrated propulsion system represents multistart (up to 50 actuations) liquid fuel propulsion system with pressure fuel feeding.

In 1999 there were launched 6 "Soyuz-U" launch vehicles with "Ikar" Injection Module, each of them simultaneously injected 4 American "Globalstar" communication satellites into orbit. Ikar's three uses on the Starsem missions were total successes, with all systems performing as planned.

The new Starsem multiple satellite dispenser also functioned flawlessly on the first three launches. This system carries four satellites: three installed vertically around the dispenser unit's central cylinder, while the fourth is mated horizontally atop the dispenser. Built by Aerospatiale Matra for Starsem, the dispenser is a lightweight, capable system that meets the needs of multiple spacecraft delivery in orbit for operators of satellite constellations.

Transfer injection orbit parameters:



minimum altitude

240 km

maximum altitude

920 km

latitude of minimum altitude

50,9º northern latitude

period of revolution

96 min

Final orbit parameters (phasing orbit):



medium radius

7298,4 km


< 0,01 km


dry "Ikar" Injection Module

2310 kg

full-loaded "Ikar" Injection Module

3210 kg

"Ikar" Injection Module overall dimensions:


2720 mm


2590 mm

Injection Module lifetime

1080000 Nf

Injection Module lifetime

no less than 30 hours

Attitude control error before satellites separation:

angular error

± 1,7°

"Ikar" Injection Module angular rotation rate don’t increase


Vernier and retro engine thrust of "Ikar" Injection Module integrated propulsion system

2943 N

Specific pulse of Ikar’s engine package thrust

3020 Nf/kg

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Page last modified: 05-06-2018 18:57:49 ZULU