An evolution of the currently operational Soyuz, the new version
of the launch vehicle meets the market's needs for a versatile,
flexible vehicle capable of performing a wide range of commercial
missions. With its successful inaugural flight on December 27,
2006 from the Baikonur Cosmodrome, the evolved Soyuz marks the
latest step in a cooperative European/Russian evolution program
and will become the centerpiece of the European launcher fleet
flying from French Guiana starting in 2011.
The evolution began
with Starsem in 1999 and the addition of the restartable Ikar
upper stage to the three-stage Soyuz, which then launched 24
satellites of the Globalstar constellation in six flights. Following
this success, Starsem introduced the flexible, restartable Fregat
upper stage from NPO Lavochkin with significantly more propellant
capacity than the Ikar. To date, the Soyuz has flown six consecutive
successful commercial missions with the Fregat upper stage.
The modernized version
of Soyuz features the following major upgrades:
a) A Digital
control system with a digital computer and inertial measurement
unit (IMU) based on proven technology, giving the Soyuz improved
navigation accuracy and control capability. The digital control
system is located primarily in the equipment bay of the third
stage and was flight-qualified during the inaugural flight of
a Soyuz 2-1a launch vehicle performed on November 8, 2004 from
the Plessetsk Cosmodrome.
The introduction
of the digital control system leads to the following advantages:
- A more flexible
and more efficient attitude control system (ACS) capable of
handling the increased aerodynamic instability generated by
the larger ST fairing.
- Increased accuracy in the flight of the first three stages
of the Soyuz.
- The ability to perform in-flight roll maneuvers as well as
in-plane yaw steering (dog-leg) maneuvers.
b) The ST-type
fairing with an external diameter of 4.110 m and a length
of 11.400 m. The ST fairing enables the Soyuz to accommodate
standard medium-class GTO telecommunications spacecraft in a
dedicated configuration and to carry smaller payloads in a multiple-manifest
configuration for LEO, MEO, SSO and escape missions. The ST
fairing was flight-qualified on October 19, 2006.
c) The RD-0124
engine is a staged combustion engine powered by a multi-stage
turbopump spun by gas from combustion of the main propellants
in a gas generator. These oxygen-rich combustion gases are recovered
to feed the four main combustion chambers where kerosene, coming
from the regenerative cooling circuit, is injected. Attitude
control is provided by main engine activation along one axis
in two planes. LOX and kerosene tanks are pressurized by the
heating and evaporation of helium coming from storage vessels
located in the LOX tank.
The RD-0124 engine adds an additional 34 seconds of Isp, significantly
increasing the overall launch vehicle performance, as demonstrated
during its inaugural flight on December 27, 2006.
The decision
of the ESA member states to introduce the new modernized Soyuz
to the European Space Port in French Guiana (CSG) is a major
step in widening the range of accessible missions for the Soyuz.
Following the construction of a new Soyuz launch pad coordinated
between the European, French and Russian S pace Agencies, the
launch vehicle's inaugural flight from the European Space Port
is scheduled for 2011.
With the introduction
of the Soyuz to CSG, this famed Russian launch vehicle becomes
an integral part of the European launcher fleet, together with
the heavy-lift Ariane 5 and the lightweight Vega. To be offered
exclusively by Arianespace to the commercial market, the Soyuz
from CSG is Europe's reference medium-class launch vehicle for
governmental and commercial missions.
