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Soyuz launches third OneWeb cluster In the midst of the coronavirus pandemic and backdropped by a report about possible impending bankruptcy of the OneWeb company, Russian specialists in Baikonur, Kazakhstan, orbited the third cluster of satellites for the OneWeb Internet constellation. The launch of the Soyuz-2-1b rocket with 34 satellites took place as scheduled on March 21, 2020, at 20:06 Moscow Time (1:06 p.m. EDT) from Site 31.
The third Soyuz mission with OneWeb satellites at a glance:
Preparing the third OneWeb mission If successful, the third launch of the OneWeb project will increase the low-orbital Internet constellation from 40 to 74 satellites. The European Arianespace consortium, which was contracted to perform the delivery, designated the mission ST28 to denote the 28th commercial launch conducted by the company and its Starsem affiliate from Baikonur. At the beginning of 2020, the ST28 mission was expected to lift off on March 18, but it was later shifted to March 21, due to logistical delays associated with the delivery of OneWeb satellites from their assembly facility in the US state of Florida. The batch of 34 satellites departed for Baikonur aboard an An-124 transport aircraft on February 24, 2020. The launch vehicle was rolled out to the launch pad on the morning of March 18, 2020. The final preparations on the pad coincided with strict measures in Baikonur, in the attempt to limit the spread of the coronavirus. Moreover, on March 19, Bloomberg.com reported that OneWeb was considering a bankruptcy filing.
Soyuz-2-1b rocket with 34 OneWeb satellites is being erected on the launch pad. According to Arianespace, its OneWeb launch campaign in Baikonur includes preparation of the satellites inside the Payload Processing Facility at Site 112, followed by fueling and mounting to the dispenser inside the Hazardous Processing Facility, HPF. The combination of the satellites and the dispenser is then mated to the Fregat upper stage, and together they are encapsulated under the fairing, forming the upper composite. The subsequent launch campaign typically follows this timeline: L-7 days (or in the night from L-7 to L-6):
L-6 to L-4 days:
L-4 days:
L-3 days:
L-2 days:
L-10 hours:
L-5 hours 10 min:
L-4 hours 20 minutes:
L-4 hours:
L-30 minutes:
L-2 minutes 25 seconds:
L-40 seconds:
L-20 seconds:
L-0:
Planned countdown milestones for the ST28 mission, according to Arianespace:
Initial launch profile
A Soyuz-2-1b rocket carrying a cluster of 34 OneWeb satellites lifted off from Site 31 in Baikonur as scheduled on March 21, 2020, at 20:06:58.196 Moscow Time (1:06 p.m. EDT). The ascent profile of the mission followed the same timeline and flight parameters employed in the previous OneWeb launch from Baikonur. After a few seconds of vertical ascent, the launch vehicle began heading northward, across Kazakhstan and Russia to align its ascent trajectory with a near-polar orbit inclined 87.4 degrees toward the plane of the Equator. The four boosters of the first stage separated 1 minute and 58 seconds after liftoff, but the core booster of the second stage continued firing until 4 minutes and 48 seconds into the flight. It separated moments after the ignition of the third stage. Two seconds later, the payload fairing, which protected the payload in the dense atmosphere, split in the two fragments and fell off. The third stage fired until 9 minutes and 23 seconds into the flight, releasing the Fregat upper stage and its cargo on a ballistic trajectory with a highest point 191 kilometers above the Earth's surface, but just short of orbital velocity. It allowed the third stage to reenter and fall into a projected area of the Arctic Ocean, north of the Canadian coast. Planned upper stage maneuvers
Exactly one minute after the separation from the third stage, the Fregat fired its main engine for 4 minutes and 11 seconds to enter a transfer elliptical (egg-shaped) orbit with the lowest point (perigee) 140 kilometers above the Earth and the highest point (apogee) 425 kilometers above's the Earth's surface, which is near the target altitude for the release of OneWeb satellites. Shortly after the planned maneuver, Head of Roskosmos Dmitry Rogozin announced that the first firing of the Fregat's engine had gone as scheduled. After its first maneuver, the Fregat climbed passively for nearly an hour. Upon reaching the apogee of the transfer trajectory, Fregat re-ignited its engine for 34 seconds to make its orbit circular at an altitude of around 450 kilometers. The first pair of OneWeb satellites was released in opposite directions from their dispenser 1 hour 11 minutes and 40 seconds after launch. In the meantime, the space tug was to re-appeared within the range of Russian ground stations at 21:40 Moscow Time (or 1 hour 34 minutes after launch), according to Rogozin. In the following 15 minutes after the release of the first pair of satellites, Fregat made a 15-second burn with its small attitude control thrusters to get in position for another release around three minutes later, this time, of four satellites. The Fregat was then programmd to repeat its thruster firing and release routine seven more times, evenly distributing the quartets of satellites along their orbit. The final four of 34 passengers were off their space tug 3 hours and 45 minutes after their liftoff from Baikonur. Around 1 hour and 20 minutes after the release of the final quartet, the Fregat was programmed to initiate a braking maneuver with its main engine which was designed to push the stage on a disposal orbit, resulting in its quick destruction in the upper atmosphere nearly six hours after launch. In total, Fregat performed 11 active maneuvers: three with the main engine and eight firings of the SOZ attitude control thrusters. OneWeb confirmed signal acquisition from all 34 satellites delivered during the mission. Following their release, the satellites were expected to maneuver to their operational positions 1,200 kilometers above the Earth's surface, using onboard electric thrusters. The satellites initially climbed to altitude of around 600 kilometers in May 2020, followed by another series of maneuvers started by most members of the group in late September 2020.
The ST28 mission timeline on March 21, 2020:
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