Soyuz ST-B launches from French Guiana with Europe’s Metop-C weather satellite
Liftoff occurred at 9:47 p.m. local time Nov. 6 (7:47 p.m. EST / 00:47 GMT Nov. 7), 2018. The mission, designated VS19 in Arianespace’s numbering system, rocketed skyward from the Soyuz Launch Complex (ELS) located in Sinnamary, French Guiana.
Metop-C arrived in French Guiana on June 26, 2018. This event kicked off the pre-launch campaign. The integration process of the Soyuz ST-B’s three rocket stages started on the very same day.
Preparations for the launch sped up in early October when fueling operations for Metop-C and the rocket’s Fregat upper stage began. In mid-October, engineers commenced tests of propulsion and electrical systems of the lower three stages of the rocket. On Oct. 25, the satellite was integrated with the Fregat upper stage in the lead up to flight.
The launch campaign entered its final phase on Oct. 29 when mission managers and the launch team began final preparations of the spacecraft and Soyuz ST-B’s lower stages. Two days later, the satellite, mated with Fregat, was encapsulated in the payload fairing, forming the upper composite. On Nov. 2, the launch vehicle consisting of three stages was rolled out to the launch zone and then the upper composite was installed atop of the launcher.
Final checks and tests of the upper composite payload fairing with the mission’s cargo tucked away inside were carried out between Nov. 3 and 5. The mission passed the Launch Readiness Review on Nov. 5, clearing the way for the start of countdown activities five hours ahead of the planned T-0.
The Soyuz ST-B ignited its four strap-on boosters and 16 seconds later it thundered off the launch pad to complete a short vertical ascent. The first phase of the flight ended about two minutes after the rocket had left the pad, when the strap-on boosters were jettisoned, leaving the launch vehicle powered by its second stage.
At T+3:36 minutes, the protective payload fairing was jettisoned, exposing the mission’s sole passenger. The detachment of the fairing was followed by the separation of the second stage about one minute later. Next, the third stage assumed control over the flight and accelerated the remaining vehicle “stack” for approximately four and a half minutes.
The third stage separated at nine minutes and 24 seconds after liftoff. This started the longest part of the flight lasting about 50 minutes.
The Metop-C satellite, attached to the rocket’s Fregat upper stage, continued its trek toward Sun-synchronous orbit (SSO). During this portion of the flight the upper stage conducted two engine burns. The spacecraft was released from the Fregat exactly one hour into the flight at an altitude of about 504 miles (811 kilometers).
Metop-C is a polar-orbiting weather satellite manufactured by Airbus Defence and Space. The spacecraft is based on the SPOT MK3 bus and features one power-generating deployable solar array. The satellite has a mass of around 4.08 metric tons and its dimensions are: 57.4 x 11.15 x 11.32 feet (17.5 x 3.4 x 3.45 meters).
Metop-C is designed to be operational for a period of about five years. During this time the satellite will be tasked with conducting global observations of weather, atmospheric composition as well as studying ocean and land surfaces. To carry this out, the spacecraft comes equipped with a set of state-of-the-art sounding and imaging instruments, such as the Infrared Atmospheric Sounding Interferometer (IASI), Global Navigation Satellite System Receiver for Atmospheric Sounding (GRAS) and the Advanced Scatterometer (ASCAT).
“IASI is MetOp’s key instrument for numerical weather prediction. It has been central to the significant improvement in weather forecasts up to 10 days ahead, over the past decade,” said Dieter Klaes, EUMETSAT Polar System Program Scientist.
Metop-C is the third, and last, satellite in the Metop series. The first two spacecraft in the constellation, Metop-A and Metop-B, were launched into space in 2006 and 2012 respectively. All three satellites will be equally spaced in orbit by 120 degrees and will form the space segment of the EUMETSAT Polar System (EPS). This system is Europe’s contribution to the Initial Joint Polar System (IJPS) which is part of a collaboration with the National Oceanic and Atmospheric Administration (NOAA).
The second generation of EPS, known as EPS-SG, is scheduled to be initiated in 2022 with the launch of the first EPS-SG satellite and deorbiting of the Metop-A spacecraft.
“Metop-C will ensure the continuity of the provision of this service until the next generation of Metop spacecraft enters into service and provides even more refined data,” said Stéfane Carlier, ESA’s Metop-C project manager. ESA, along with the French space agency CNES, is also engaged in the EPS project.
The Soyuz ST-B rocket that was used for the Nov. 6 mission is a four-stage launch vehicle that is composed of four boosters (the first stage) affixed to a central core (the second stage), a third stage, and a restartable Fregat upper stage. It also included a payload adapter/dispenser and fairing.
The Fregat is an autonomous and flexible upper stage that is designed to operate as an orbital vehicle. It extends the capability of the Soyuz launcher to cover the full range of orbits.
Tuesday’s mission was Arianespace’s eighth launch of 2018. The company’s next scheduled mission is currently slated for Nov. 20 when a Vega rocket is expected to orbit the Mohammed VI-B Earth-observing satellite for Morocco.
Video courtesy of Arianespace
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