The payload section of the Soyuz rocket with six OneWeb satellites. Credit: Arianespace
The payload section of the Soyuz rocket with six OneWeb satellites. Click to enlarge. Credit: Arianespace
Payload section inside mobile service tower after its integration with the Soyuz rocket. Click to enlarge. Credit: Arianespace
Soyuz ST-B lifts off with a sextuplet of OneWeb satellites on Feb. 27, 2019. Click to enlarge. Credit: Arianespace
Payload fairing separation during VS21 mission as seen by an onboard camera. Credit: Arianespace
An artist rendering illustrating the release of the first pair of OneWeb satellites during the VS21 mission. Credit: Arianespace
Spacecraft separation during VS21 mission as seen by onboard camera No. 2 (top) and No. 1 (middle) and camera No. 4 (bottom). Credit: Arianespace
Russian rocket launches first OneWeb cluster
A Russian-built Soyuz rocket, procured by European consortium Arianespace, successfully delivered first six OneWeb satellites on Feb. 27, 2019, for a London-based company, kicking off the deployment of a nearly 650-bird-strong global Internet constellation in low orbit. The launch took place as scheduled at 6:37 p.m. local time (4:37 p.m. EST/21:37 GMT).
Soyuz ST-A mission (VS21) with six OneWeb satellites at a glance:
Launching OneWeb satellite constellation
The first six OneWeb F6-series satellites, along with four Mass Flight Simulators, MSF, to enter orbit were assigned to the 21st Soyuz launch from the European facility near Kourou, French Guiana. According to the naming convention of the Arianespace company, which operates Soyuz-2 (ST), Ariane and Vega rockets flying from Guiana, the mission was designated VS-21, where "V" stood for "Vol" ("flight" in French) and "S" for Soyuz.
The wedge-shaped OneWeb satellites were designed to fit into their launch vehicles attached to a pipe-shaped holding structures like corn on a cob. Each OneWeb payload dispenser for the Soyuz-2 rocket is capable of accommodating up to 32 spacecraft per launch, but during the first mission, the developers decided to fill only six positions with operational satellites and four others with mass simulators.
The final assembly of the first six spacecraft within the F6 series was conducted at an Airbus facility in Toulouse, France. Switzerland-based APCO Technologies built four mass simulators and RUAG Space AB, of Linköping, Sweden, provided a dispenser attached to the Fregat upper stage and designed to hold up to 32 satellites during their ascent into space and then to release them upon reaching the operational orbit.
Known specifications of the OneWeb F6 satellite:
Difficult preparations for flight
In the middle of 2015, Arianespace said that the first OneWeb mission would be launched in late 2017, but various delays pushed the first launch to November 2018. By August of that year, the first test flight from Kourou had to be postponed until February 2019, apparently due to delays with the production of the spacecraft. At the same time, the first OneWeb launch from Baikonur was now possible no earlier than the end of summer or the beginning of fall 2019 and it was soon postponed to the last quarter of 2019. The first launch of the satellites from Vostochny slipped to 2020.
The first launch campaign for a OneWeb F6 mission in French Guiana began on Sept. 3, 2018, with the review of the integration of the first, second and third stages of the Soyuz ST-B rocket assigned for the mission. From November 20 to Dec. 15, 2018, all three booster stages underwent pneumatic and propulsion system tests inside the MIK processing building of the ELS facility.
In parallel, the processing of the Fregat-M stage took place from September 5 to Dec. 15, 2018. On December 20, the space tug was moved to the FCube building in preparation for fueling.
Still by the middle of December 2018, the launch had to be delayed again from February 7 to February 19, 2019. The postponement was the result of a schedule conflict with the upcoming launch of the Ariane-5 rocket set for February 5 and the following two-week processing cycle at ground facilities in Kourou.
The OneWeb satellites for the mission finally arrived at the launch site on Jan. 22, 2019, and from January 23 to February 7, they and four mass simulators were attached to their payload dispenser.
From January 23 to Feb. 7, 2019, Fregat was scheduled to undergo fueling with its hypergolic and highly toxic propellants, which was interrupted sometimes in the last days of January, after a crack had been discovered in a helium pressurization line, a part of the space tug's propulsion system. By that time, the vehicle had already received its load of hazardous oxidizer. Specialists at NPO Lavochkin initially proposed to patch the line, but officials at Arianespace rejected the idea. There were also proposals to swap the damaged Fregat for an identical vehicle assigned to launch the latest batch of o3b satellites in March 2019. The plan apparently involved draining the affected Fregat and even shipping it back to NPO Lavochkin in Russia for repairs.
In the end, it was decided to try repairing the vehicle in place without draining the propellant. A team of specialists from NPO Lavochkin departed for French Guiana around January 31 to perform the dangerous operation.
There were reports about a possible delay of the OneWeb mission until February 26 or 27, but after the crack was successfully welded on February 4, the launch date was set for February 22. However, on February 12, OneWeb announced the delay of the launch until February 26.
On February 18, Fregat arrived at S3B building, where the next day, the payload dispenser holding the satellites was installed on top of the stage. On the same day, the resulting composite was covered with a payload fairing.
On February 21, several hours after an anomaly with the third stage of the Soyuz-2-1b rocket during the otherwise successful launch of the EgyptSat-A satellite, OneWeb announced a delay of its mission from February 26 for at least 24 hours. On the same day, Arianespace said that the rollout of the rocket and its payload to the launch pad had been postponed and a new launch date would be announced shortly.
The launch vehicle was rolled out to the launch pad on February 23 with the goal of launching the mission on February 27. During the day after the rollout, the payload section was lifted and installed on top of the launch vehicle.
Planned countdown milestones for the VS-21 mission on Feb. 27, 2019:
How OneWeb satellites were launched
A Soyuz-2 (ST-B) rocket carrying the first cluster of OneWeb satellites lifted off from the ELS complex in Kourou, French Guiana, on Feb. 27, 2019, at 6:37 p.m. local time (4:37 p.m. EST). It was 00:37 Moscow Time on February 28.
After eight seconds of vertical ascent from a sea-side pad, the launch vehicle began tilting northward, heading over the Atlantic Ocean to align its ascent trajectory with a near-polar orbit inclined 87.77 degrees toward the plane of the Equator.
During a nine-minute powered ascent, the four boosters of the first stage, the payload fairing and the second stage were dropped over the Atlantic, followed by the third stage separating and eventually splashing down between Canada and Greenland.
In the meantime, the Fregat upper stage and its payloads were left on a ballistic trajectory just short of orbital velocity. The Fregat then fired its engine for around four minutes to enter an initial transfer orbit, which the stack climbed passively for 43 minutes.
During the ascent of the Soyuz rocket and the most critical maneuvers of the Fregat upper stage, the mission was crossing the communications range of various ground stations from Guiana to Bermuda Islands to the Arctic Ocean, downlinking data about its status.
Upon reaching the apogee (highest point) of the transfer trajectory, Fregat re-ignited its engine for around two minutes to make its orbit circular at an altitude of around 1,000 kilometers.
The two-step release of the satellites began 4.5 minutes after the Fregat's second maneuver and was completed one hour 22 minutes and 30 seconds after the liftoff, while within range of a ground station in Nova Norcia in Western Australia. According to NPO Lavochkin, the first two OneWeb spacecraft were separated at 01:40 Moscow Time on February 28 and four more satellites were separated at 01:59 Moscow Time.
The Fregat was then went through a series of seven maneuvers with its attitude control thrusters, DU SOZ, to test operations for the release of the entire 32-satellite batch in future OneWeb missions.
Following the deployment, the Fregat was programmed to conduct a deorbiting maneuver with its main engine, directing the stage on a reentry path over the southern section of the Indian Ocean, less than 4.5 hours after launch.
Shortly after the launch, all six satellites were reported to be healthy and they were expected to use their own propulsion systems to climb to an altitude of around 1,200 kilometers.
The VS-21 mission timeline:
NORAD registered six OneWeb satellites in the following orbits:
OneWeb also announced that it had invited different schools, which would be using its service, to give a proper name to each satellite. According to the company, the satellites launched in the first mission were named as following: