Soyuz-ST-B Arianespaces Flight VS19 Successfully Launches MetOp-C Satellite
Arianespace launched a new European weather satellite Tuesday, using a Soyuz rocket to deploy the Metop-C spacecraft into orbit around the Earth. Liftoff from the Centre Spatial Guyanais in Kourou, French Guiana, occurred at 21:47:27 local time (00:47 UTC on Wednesday).
The Meteorological Operational (Metop) satellites are operated by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), making up the EUMETSAT Polar System (EPS). Operating in near-polar sun-synchronous orbits, Metop satellites carry a suite of instruments to study and monitor the Earth’s weather.
The EUMETSAT Polar System contributes to the Initial Joint Polar System (IJPS), an international partnership between EUMETSAT and the United States National Oceanic and Atmospheric Administration (NOAA). IJPS, which also incorporates the NOAA’s Polar Operational Environmental Satellites (POES), sees the two agencies share data and use each other’s ground stations to control their satellites and downlink data. The NOAA has also provided several of the instruments that fly aboard Metop satellites.
Metop is one of two series of weather satellites operated by EUMETSAT: the organization also operates a fleet of spacecraft in higher geostationary orbits, Meteosat. EUMETSAT also partners with the European Space Agency (ESA) and European Commission on the Sentinel Earth science missions, and with ESA, NOAA and NASA on the Jason ocean research satellites.
Constructed by Airbus Defence and Space – formerly EADS Astrium – the 4,084-kilogram (9,004 lb) Metop-C is based on the SPOT Mk.3 satellite bus, a platform originally developed for France’s SPOT imaging spacecraft. The satellite is three-axis stabilized and uses a deployable solar array to generate power for its onboard systems.
The sun-synchronous orbit in which Metop satellites operate allows each spacecraft to pass over the Earth’s surface at approximately the same mean solar time in each location. Metop-C will orbit the Earth at an altitude of approximately 811 kilometers (504 miles, 438 nautical miles), inclined at 98.74 degrees. The orbit Metop satellites use is designed so they can observe points on the surface in the mid-morning – about 09:30 – in their local time. NOAA’s satellites use orbits suited to afternoon observations, complementing Metop’s data.
Metop-C will be the third member of the Metop constellation, joining the Metop-A and Metop-B satellites which were launched in 2006 and 2012 respectively. While each Metop satellite is designed to operate for five years, both Metop-A and Metop-B have exceeded their design lives and remain in service. The three spacecraft are of the same design, carrying the same suite of instruments.
Three of these instruments were provided by the NOAA. The Advanced Very High Resolution Radiometer 3 (AVHRR/3), Advanced Microwave Sounding Unit A (AMSU-A) and Space Environment Monitor 2 (SEM-2) are identical to instruments that were flown aboard the NOAA’s fifth-generation POES satellites, that were being launched at the time the Metop spacecraft were developed. All three instruments have previously flown aboard five US weather satellites, beginning with NOAA-15 in 1998, and the two previous Metop spacecraft.
Metop-C is the final first-generation Metop satellite to be launched. The Metop Second Generation (Metop-SG or MSG) satellites are scheduled to begin launching in the early 2020s. Metop-SG will use two satellites equipped with different instruments to collect complimentary data, with three satellites of each type launching sequentially to continue data collection for almost another thirty years.
Arianespace used a Soyuz ST-B rocket with a Fregat-M upper stage to place Metop-C into orbit. The Soyuz ST-B is a version of the Soyuz-2-1b vehicle, optimized for launch from Arianespace’s Centre Spatial Guyanais launch site in French Guiana.
Both previous Metop satellites also launched aboard Soyuz-2 rockets. Metop-A was the first payload to be launched aboard a Soyuz-2, flying on the second Soyuz-2-1a in October 2006, after the rocket’s maiden flight had carried an inert, obsolete, spacecraft. This was also the first Soyuz-2 launch with a Fregat upper stage.
Metop-B was launched atop a Soyuz-2-1a/Fregat-M in September 2012. Both launches were conducted by Arianespace’s subsidiary Starsem, with the rockets flying from the Baikonur Cosmodrome in Kazakhstan.
Soyuz-2 is a modernized version of Russia’s Soyuz family of rockets. First flown in 1966, Soyuz was an upgraded version of the earlier Voskhod rocket, itself developed from Sergei Korolev’s R-7 missile. Soyuz-2 introduced upgraded first and second stage engines and a new digital flight control system.
Three different versions of the Soyuz-2 have been flown: The Soyuz-2-1a is the basic version, modernizing the previous-generation Soyuz-U, while the Soyuz-2-1b also upgrades the upper stage with an RD-0124 engine. The Soyuz-STA and STB configurations incorporate additional modifications, including flight termination packages, necessary for operation from French Guiana.
The third configuration, Soyuz-2-1v, is a smaller vehicle without the first stage boosters used on the Soyuz-2-1b. However, it is only launched from Russia.
The Soyuz-STB/Fregat-M is a four-stage rocket, consisting of the three-stage Soyuz and the Fregat upper stage. All three stages of the Soyuz burn RG-1 fuel – a refined petroleum product – oxidized by liquid oxygen, while Fregat uses storable propellant. Designated VS19 under Arianespace’s numbering scheme for its missions, Soyuz will take just over an hour to place Metop-C into orbit.
The Metop-C mission was Arianespace’s eighth launch of 2018. It is also the twelfth flight of Soyuz this year, although only one of the year’s previous launches was conducted by Arianespace. Tuesday’s launch took place less than a month after the failure of a Soyuz-FG launch, in a mission out of the Baikonur Cosmodrome that was to carry a crew of two to the International Space Station aboard the Soyuz MS-10 spacecraft. Soyuz has since returned to flight with two successful launches for the Russian military in the last fortnight. This was the third success.
Up to five more Soyuz launches could take place before the end of the year. The next of these is scheduled for 18 November, with a Soyuz-FG launching the Progress MS-10 resupply mission to the International Space Station. If this goes to plan, another Soyuz-FG will launch at the start of December with Soyuz MS-11 and a crew of three bound for the station.
Arianespace has one more Soyuz launch on their books for 2018, planned for mid-December with France’s CSO-1 reconnaissance satellite aboard. Two more launches at the end of the year – from the Vostochny and Baikonur Cosmodromes respectively – will deploy a pair of Kanopus-V spacecraft and the EgyptSat-A remote sensing mission.
Before next month’s Soyuz launch, Arianespace will fly missions with both of the other rockets in their fleet. Around 20 November a Vega rocket will launch Mohammed VI-B for Morocco, while an Ariane 5ECA is expected to lift off in early December with India’s GSAT-11 communications satellite and South Korea’s geostationary Cheollian-2A weather satellite. An additional Ariane 5 launch could also take place later in December.
