Arianespace Soyuz ST-A launches Sentinel-1A mission
Arianespace launched a Soyuz ST-A rocket on a mission to loft the Sentinel-1A mission into orbit from the European Spaceport “Centre Spatial Guyanais (CSG)” in Kourou, French Guiana. Launch of the Earth observation satellite – that will deliver essential data for Europe’s Copernicus program from a Sun-synchronous orbit – was on schedule at 6:02 pm local time (8:02 pm UTC).
Soyuz ST-A Launch:
The veteran Soyuz launch vehicle is a descendent of the R-7 Semyorka, the world’s first intercontinental ballistic missile. The R-7 was designed by Sergei Korolev, and first flew in 1957. A modified version was used to launch the first satellite, Sputnik 1, on 4 October of that year.
The R-7 formed the basis for the Luna, Vostok, Voskhod, Molniya and Soyuz families of rockets, and to date all Soviet and Russian manned spaceflights have been launched using rockets derived from the R-7.
The Soyuz, which first flew in 1966, was a modification of the Voskhod rocket featuring an upgraded and lighter telemetry system, and more fuel efficient engines. It was initially used to launch only Soyuz spacecraft; however with the introduction of the Soyuz-U in 1973 it began to launch other satellites as well.
The Soyuz-U, which remains in service, is the most-flown orbital launch system ever developed, having made around 750 flights to date, plus around 90 more in the Soyuz-U2 configuration optimised to use synthetic propellant.
The Soyuz-2 was developed from the older Soyuz models, and features digital flight control systems and modernised engines. It first flew in 2004. Two variants are currently in service; the Soyuz-2-1a, and the Soyuz-2-1b which features an RD-0124 third stage engine which provides additional thrust. The RD-0124 was declared operational on 3 May 2011.
A third configuration, the Soyuz-2-1v has since been added to the family. It features an NK-33 engine in place of the RD-108A used on the core stages of the other configurations, and does not include the strapon boosters used by other configurations.
The Soyuz-2 forms the basis for the Soyuz-ST rocket, which has been optimised to fly from Kourou, and also incorporates a flight termination system and a modified telemetry system.
The vehicle consists of four boosters (first stage), a central core (second stage), a third stage, and the restartable Fregat-M upper stage (fourth stage). Each vehicle also includes a payload adapter/dispenser and fairing.
The inaugural flight of the upgraded Soyuz 2-1b launch vehicle was successfully performed on December 27, 2006, launching the Corot scientific spacecraft for the French Centre National d’Etudes Spatiales.
As part of the Soyuz’ upgrades for its operations from the Spaceport, the launcher’s flight control system is modernized with a digital control system. This system incorporates a digital computer and inertial measurement unit that are based on proven technology – giving the Soyuz improved navigation accuracy and control capability.
The new digital control system provides a more flexible and efficient attitude control system, and it gives the additional flight control authority required when the new, enlarged Soyuz ST payload fairing is installed on the vehicle. In addition, it improves flight accuracy for the Soyuz’ first three stages, and provides the ability to perform in-flight roll maneuvers as well as in-plane yaw steering (dog-leg) maneuvers.
This Arianespace flight is designated VS07 in the company’s mission numbering system, denoting the seventh Soyuz liftoff from French Guiana since the medium-lift vehicle’s October 2011 service entry.
Payload performance for the flight was more than 2,270 kg., including an estimated 2,157 kg. for Sentinel-1A – which was developed by an industrial consortium led by prime contractor Thales Alenia Space.
Sentinel-1 is the first satellite dedicated to Europe’s Copernicus environmental monitoring program.
Copernicus is a program of the European Commission in partnership with the European Space Agency (ESA), and is designed to give Europe complete independence in the acquisition and management of data for Earth environmental, civil safety and humanitarian purposes.
The new satellite carries an advanced synthetic aperture radar that works in several specialized modes to provide detailed imagery for monitoring the oceans, including shipping lanes, sea ice and oil spills. It also provides data to map changing land cover, ground deformation, ice shelves and glaciers, and can be used to help emergency response when disasters such as floods strike and to support humanitarian relief efforts at times of crisis.
The Sentinel-1 mission, as with Sentinel-2 and Sentinel-3, is a constellation of two identical satellites to provide optimal global coverage. Its sister satellite, Sentinel-1B, will follow in 2015.
The spacecraft – which is expected to serve for at least seven years from its Polar, Sun-synchronous at an altitude of 693 km - is 2.8 m long, 2.5 m wide, 4 m high with 2×10 m-long solar arrays and a 12 m-long radar antenna. It sports C-band synthetic aperture radar (SAR) at 5.405 GHz.
“The design of Sentinel-1 with its focus on reliability, operational stability, global coverage and quick data delivery is expected to enable the development of new applications and meet the evolving needs of Copernicus,” note ESA – who class the spacecraft as an outstanding example of Europe’s technological excellence.
(Images via ESA and Arianespace).