Arianespace will make its final launch of 2018 on Tuesday, using a Soyuz rocket to distribute a high definition imaging satellite for the French military. Soyuz is scheduled to lift from Center Spatial Guyanais – near Kourou, French Guiana – at 13:37:14 local time (16:37 UTC), using its CSO-1 payload just over an hour later.
Tuesday's launch will distribute CSO-1, the first of three satellites that will form Composante Spatiale Optique (CSO) or Optical Space Component. These spacecraft will serve the French military, replacing the previous Helios reconnaissance satellites. In order to develop the constellation, France's Direction Générale de Armage (DGA – Directorate-General for Armaments) has entered into a partnership with the national space organization CNES.
Airbus Defense and Space are the main contractor of the three CSO satellites, which are based around its AstroSat-1000 platform. Each satellite has a mass of 3 655 kilos (7 859 pounds) and is expected to work for at least ten years. The image systems were produced by Thales Alenia Space. From solar-synchronized orbit at an altitude of about 800 kilometers (497 miles, 432 nautical miles), CSO-1 is expected to form the earth at resolutions of approximately 35 cm.
CSO-1 is the first satellite in France's third generation of reconnaissance satellites, followed by two pairs of Helios spacecraft. The first dedicated French military reconnaissance satellite was Helios-1A, launched on top of an Ariane 4 rocket in July 1995.
The almost identical Helios-1B was used in December 1999 to replace it. A second-generation Helio spacecraft with high resolution imaging system followed: Helios-2A was deployed by an Ariane 5G + on December 18, 2004 and Helios-2B launched an Ariane 5GS five years later, to a minute. Remarkably, CSO-1 is scheduled to lift the anniversary of both of these launches, although the launch for Tuesday's mission is eleven minutes later than for the two Helios launch.
Once all three satellites have been launched, CSO will work with two satellites in the 800-kilometer lane, while CSO-2 will use a lower lane for higher resolution. CSO-2's mission has been described as one of the identification features observed by its sister satellites in the higher circulation. CSO-2 is currently slated for launch 2020 or 2021, with CSO-3 included in constellation one year or two later.
CSO-1 will be launched by Paris-based Arianespace, which has used all of France's previous reconnaissance satellites. Arianespace operates a fleet of three different types of rockets: Vega is used to launch smaller satellites, Ariane 5 carries the heaviest payloads – usually pairs of geostationary communications satellites – and the Russian Soyuz rocket fills the capacity between these two vehicles. Tuesday's mission will use Soyuz, in its Soyuz ST-A configuration with a Frigate-M upper scene.
Soyuz ST-A is based on the Soyuz 2-1a rocket, which contains modifications specific to using Arian Space launch center, Center Spatial Guyanais (CSG), located near Kourou in French Guiana. Soyuz-2-1a is one of three modernized versions of former Soyuz rockets, derivative of Sergei Korolev's R-7 missile used for Russian (and former Soviet) satellites and manned space flight refinements since the 1960s.
Soyuz-2-1a made its first suborbital test flight in 2004 and its first orbital start two years later. It introduced upgraded first and second-stage engines over the former Soyuz-U generation, as well as a digital flight control system and other enhancements. A second Soyuz-2 configuration, Soyuz-2-1b (powered by Arianespace as Soyuz ST-B) also has an upgraded third-stage engine. The smaller Soyuz 2-1v is designed to carry lighter payload, but this version of the rocket is not used by Arianespace.
Soyuz is a three-stage rocket, although the first and second stages burn together at the liftoff. In order to reach higher levels or perform more complex missions, Soyuz can be used in conjunction with an upper stage. For Tuesday's mission, a Frigate-M will be used to introduce CSO-1 into its planned solar synchronous breakthrough. Frigate is the most common type of top stage flying on Soyuz; It is based on propulsion systems in the Soviet Union's late interplanetary probes and can restart the engine several times during a long extended mission to ensure delivery of payload in the required track.
Tuesday's launch is the 20th flight of a Soyuz from French Guiana. The Soyuz launch, Ensemble de Lancement Soyouz (ELS), was first used in October 2011 for the deployment of a pair of Galileo navigation satellites. Including the vehicle performing the CSO-1 mission, six Soyuz ST-A and fourteen Soyuz ST-B rockets have resigned Kourou. Everything except one of Soyuz launched from Kourou – a Soyuz ST-B whose Frigate upper stage malfunction – has successfully completed its mission.
Soyuz launches also take place from Baikonur Cosmodrome in Kazakhstan and Plesetsk and Vostochny Cosmodromes in Russia.
Arianespace's name for Tuesday's mission is VS20. The launch begins with the ignition of first and second-stage engines about sixteen seconds before the liftoff. The first stage of the Soyuz ST-A vehicle consists of four boosters with RD-107A engines, grouped around the second stage, powered by a single RD-108A.
The rocket engines will build up power while the rocket is held down and reaches full effect at the T-1 second mark in the countdown. At zero, the starting board opens the swing arms, and Soyuz begins to climb the space.
The first and second stages of the rocket will burn for the first minute and fifty-two seconds of pitch. At this point, they close the four first step enhancers that vent a surplus of oxygen to push their noses away from the rocket as they differ. The pattern from the separation boosters is called Korolevkorset after the rocket chief designer.
After the first scene differs, Soyuz continues to fly under the power of its second stage for another two minutes and 49 seconds. About thirty-two seconds before the end of the second flight, the payload will differ from the rocket's nose.
The second and third stages are designed to separate while the second stage still shoots. The third stage ignites its RD-0110 engine while RD-108A is still burning because the propellant remains settled in the tank in the third stage. The third stage will shoot for four minutes and two seconds before Freegat is used to continue CSO-1's journey to orbit.
Sixty seconds after being separated from the third stage, Frigate will ignite its S5.98M engine for the first of three planned burns. This will last eight minutes and fifty five seconds, setting up a first parking lot. After a 35-minute, 34-second Coastal phase Frigate will reboil for another 89 seconds, circulates the orbit.
CSO-1 will separate from Frigate five minutes after completion of the second burn – approximately one hour and 44 seconds after lifting. Frigate will make its third and final burn four seconds short 51 minutes later, with this 55-second maneuvering serving to deorbit the scene to not leave unnecessary junk in circulation.
The CSO-1 launch is Eleventh and Last for Arianespace 2018, after two previous Soyuz missions, two Vega launches and six Ariane 5's. Arian Space's next launch is planned at the end of January with HS4-SGS1 and GSAT-31 on-board communication satellites and Ariane 5, while the next Soyuz launch from Kourou is expected to carry four O3b satellites in the first quarter.
A further Soyuz launch is expected from Russia before the end of the year: A Soyuz-2-1a / Frigate M vehicle is scheduled to lift off from Vostochny Cosmodrome on December 27 with its primary payload a pair of Kanopus-V remote sensing satellites.