to Space launchers main page
TwitterpinterestFacebook



Proton



OneWeb2


3


4


5


6


oneweb7


OneWeb9


OneWeb9


 

ADVERTISE! | DONATE! | SUBSCRIBE!

 

Soyuz launches 11th OneWeb cluster

A Soyuz-2-1b/Fregat rocket delivered a fresh batch of 36 satellites from Vostochny Cosmodrome on Oct. 14, 2021, for the UK-based OneWeb company. It was the seventh launch of the year into the OneWeb constellation, boosting it from 322 to 358 spacecraft or over the half of the planned 648 satellites.

launch

The 11th Soyuz mission with OneWeb satellites at a glance:

Mission and spacecraft designation
ST36 OneWeb (Satellites 323-358)
Launch vehicle
Soyuz 2-1b /Fregat No. 123-14
Payload fairing
81KS.1000-0 No. V15000-052
Launch site
Launch date and time
2021 Oct. 14, 12:40:10.356 Moscow Time (5:40 a.m. EDT)
Payload mass (including dispenser)
36 satellites 147.5 kilograms each*, 5,814 kilograms total
Target orbit
Altitude: ~450 kilometers, inclination 87.4 degrees**
Satellite operational life span
No less than 7 years
Satellite dimensions in transport position
1,200 x 925 x 1,272 millimeters

*According to Roskosmos each satellite has a mass of 144.5 killograms +/– 2.5 kilograms.

**Satellites will use their own propulsion system to enter a 1,200-kilometer operational orbit

SUPPORT THIS PROJECT!

Donate

Preparing the 11th OneWeb mission

The 11th OneWeb mission, originally scheduled for launch on September 14, used a time slot that had been officially reserved for the Luna-Glob mission which had never had a real chance to fly in 2021. (INSIDER CONTENT) Once the Luna-Glob launch campaign was formally postponed until 2022, the available capacity at the Vostochny spaceport was provided for the OneWeb launch campaign.

On Aug. 11, 2021, Roskosmos announced that the specialists of the joint team from the Vostochny branch of the TsENKI ground infrastructure center and NPO Lavochkin had removed the Fregat upper stage for the mission from its storage and installed it in the processing rig inside the Spacecraft Processing Building, MIK KO, of the center's processing complex. On September 1, Roskosmos said that pneumatic and electric tests of the Fregat had started on August 12 and were expected to be completed by September 6. At that time, the launch was already scheduled for October, according to Roskosmos. Fregat was transferred to the fueling station around September 7. The loading of propellant and pressurized gases aboard the upper stage was completed by September 30.

An 124-100 transport plane delivered the 36 satellites for the mission to the Ignatievo airport in Blagoveshensk on Sept. 25, 2021. On October 6, the fully assembled satellite cluster was rolled inside the rocket's protective fairing, completing the assembly of the payload section. On October 8, the payload section was integrated with the launch vehicle and was ready for the rollout to the launch pad. The meeting of the State Commission authorizing the trip to the pad was scheduled for October 9, Roskosmos said.

On October 11, at 7 a.m. local time in Vostochny (01:00 Moscow Time), the Soyuz-2-1b rocket with 36 OneWeb satellites started moving from the vehicle assembly building to the launch pad.

pad


 

Countdown milestones for a typical OneWeb mission, according to Arianespace:

PRE-LAUNCH EVENTS
Time (h:min:sec)
Beginning of the meeting for launcher fueling authorization (BTR)
-05:04:08
Beginning of launch vehicle fueling
-04:33:33
Completion of launch vehicle fueling
-01:33:33
Test bars at 1 kHz tone
-00:30:00
"Key-to-launch" command (beginning of Soyuz synchronized sequence)
-00:06:00
Fregat transfer to onboard power supply
-00:05:00
Upper Composite umbilical drop-off command
-00:02:25
Ground-board power transfer
-00:00:45
Lower stage mast retraction
-00:00:19
Ignition
-00:00:16
Preliminary thrust level
-00:00:11
Liftoff
00:00:00

 

Launch profile of the OneWeb mission originating from Vostochny

ObneWeb

Approximate ground track of the OneWeb mission.


A Soyuz-2-1b rocket carrying a cluster of 36 OneWeb satellites lifted off from 1S pad in Vostochny on Oct. 14, 2021, at 12:40:10.356 Moscow Time (5:40 a.m. EDT).

The ascent profile of the mission had a timeline and flight parameters similar to those employed in the previous OneWeb launches from Vostochny. After a few seconds of vertical ascent, the launch vehicle headed northward to align its ascent trajectory with a near-polar orbit inclined 87.4 degrees toward the plane of the Equator. The particular ground track employed during the ascent to orbit from Vostochny had so far been unique to OneWeb missions.

The four boosters of the first stage separated 1 minute and 58 seconds after liftoff (L+117.8 sec.), but the core booster of the second stage continued firing until 4 minutes and 48 seconds into the flight (L+287.5 sec.). In the midst of its operation, the payload fairing protecting the payload in the dense atmosphere split into two halves and dropped off at L+3 minutes 35 seconds (L+215.2 sec.). Immediately after the separation of the second stage, the aft section of the third stage split into three fragments and separated at L+292.1 seconds.

The fragments of the rocket were expected to fall at Drop Zones No. 873 and 875 in the Aldan and Kobyask Districts of the Sakha (Yakut) Republic in the Russian Far East.

The third stage continued firing until 9 minutes and 22 seconds into the flight (T+559.2 seconds), releasing the Fregat upper stage and its cargo on a ballistic trajectory with an apogee of 249 kilometers, just short of orbital velocity at L+562.5 seconds. This allowed the third stage to reenter and fall back to Earth at a predicted remote area of the ocean instead of reaching orbit.

Upper stage maneuvers

scenario

One minute after separation from the third stage, Fregat fired its main engine for 307 seconds to enter an elliptical (egg-shaped) 150 by 427-kilometer transfer orbit with the highest point (apogee) near the target altitude for the release of OneWeb satellites.

After its first maneuver, Fregat climbed passively for nearly an hour. Soon after an orbital insertion, the space tug and its passengers left the communications range of ground stations for 1 hours 18 minutes and 42 seconds, therefore Fregat's second maneuver and the separation of the first batch of satellites took place out of contact with mission control. The restart of the Fregat's engine for a 31-second firing then happened near the apogee of the transfer orbit making it circular at an altitude of around 450 kilometers.

The first quartet of OneWeb satellites was released in opposite directions from their dispenser 1 hour 18 minutes and 20 seconds after launch. It was followed by nearly 16 minutes later by a 15-second firing of the small attitude control thrusters, SOZ, aboard Fregat to get the vehicle in position for the second quartet drop around three minutes later.

Roskosmos confirmed that the second quartet of satellites had been successfully deployed at 14:17 Moscow Time (7:17 a.m. EDT).

Fregat was programmed to repeat its thruster firing and the four-satellite release routine seven more times, evenly distributing quartets of satellites along their orbit.

Next time, the Fregat reentered the communications range, mission control confirmed that the 3rd, 4th, 5th and 6th batch of OneWeb satellites had indeed separated from their carrier. Then, still in direct view of ground stations, the 7th quartet also disembarked from the space tug. However, the vehicle then again went out of communications range for another 1 hour 18 minutes and 55 seconds.

The final four of the 36 OneWeb passengers separated from their space tug 3 hours 51 minutes and 40 seconds after their liftoff from Vostochny. But the successful separation of the two final quartets of satellites would not be confirmed until sometimes later, when the empty Fregat stage reappeared in the view of ground stations.

Around an hour after the release of its final passengers, Fregat was programmed to initiate a braking maneuver with its main engine designed to push the stage on a disposal orbit, resulting in its quick destruction in the upper atmosphere nearly six hours after launch over a remote area of the Pacific Ocean. In total, Fregat performed 11 active maneuvers: three with its main engine and eight firings of the SOZ attitude control thrusters.

As in all previous missions, OneWeb satellites had to use their own electric propulsion systems to climb to an operational orbit of around 1,200 kilometers.

 

Timeline of a typical OneWeb mission from Vostochny:

Event
Scheduled elapsed time
Liftoff
0
Stage I separation
1 minutes 58 seconds (117.8 sec.)
Payload fairing separation
3 minutes 35 seconds (214.6 sec.)
Stage II separation
4 minutes 48 seconds (287.5 sec.)
Stage III separation
9 minutes 20 seconds
Fregat main engine firing 1 begins
10 minutes 22 seconds
Fregat main engine firing 1 ends
15 minutes 29 seconds
Fregat main engine firing 2 begins
1 hour 13 minutes 40 seconds
Fregat main engine firing 2 ends
1 hour 14 minutes 12 seconds
Separation 1 of first four OneWeb satellites
1 hour 18 minutes 20 seconds
Fregat attitude control system firing 1 begins
1 hour 34 minutes 10 seconds
Fregat attitude control system firing 2 ends
1 hour 34 minutes 25 seconds
Separation 2 of four OneWeb satellites
1 hour 37 minutes 30 seconds
Fregat attitude control system firing 2 begins
1 hour 53 minutes 20 seconds
Fregat attitude control system firing 2 ends
1 hour 53 minutes 34 seconds
Separation 3 of four OneWeb satellites
1 hour 56 minutes 40 seconds
Fregat attitude control system firing 3 begins
2 hours 12 minutes 30 seconds
Fregat attitude control system firing 3 ends
2 hours 12 minutes 42 seconds
Separation 4 of four OneWeb satellites
2 hours 15 minutes 50 seconds
Fregat attitude control system firing 4 begins
2 hours 31 minutes 40 seconds
Fregat attitude control system firing 4 ends
2 hours 31 minutes 51 seconds
Separation 5 of four OneWeb satellites
2 hours 35 minutes 00 seconds
Fregat attitude control system firing 5 begins
2 hours 50 minutes 50 seconds
Fregat attitude control system firing 5 ends
2 hours 51 minutes 00 seconds
Separation 6 of four OneWeb satellites
2 hours 54 minutes 10 seconds
Fregat attitude control system firing 6 begins
3 hours 10 minutes 00 seconds
Fregat attitude control system firing 6 ends
3 hours 10 minutes 08 seconds
Separation 7 of four OneWeb satellites
3 hours 13 minutes 20 seconds
Fregat attitude control system firing 7 begins
3 hours 29 minutes 10 seconds
Fregat attitude control system firing 7 ends
3 hours 29 minutes 17 seconds
Separation 8 of four OneWeb satellites
3 hours 32 minutes 30 seconds
Fregat attitude control system firing 8 begins
3 hours 48 minutes 20 seconds
Fregat attitude control system firing 8 ends
3 hours 48 minutes 26 seconds
Separation 9 of four OneWeb satellites
3 hours 51 minutes 40 seconds
Fregat main engine firing 3 begins for deorbiting
4 hours 50 minutes 05 seconds
Fregat main engine firing 3 ends for deorbiting
4 hours 50 minutes 35 seconds
Mission end
4 hours 52 minutes 58 seconds

 

To be continued

Bookmark and Share

 

Page author: Anatoly Zak; Last update: October 14, 2021

Page editor: Alain Chabot; Last edit: October 13, 2021

All rights reserved

 

insider content

 

logo

The official logo of the 11th OneWeb mission, ST36. Credit: OneWeb


orto

Payload arrangement for the OneWeb launch on the Soyuz rocket with 36 satellites. The satellites are attached to a 5.5-meter-tall, 1.7-meter-in-diameter adapter built by RUAG Space. Credit: Arianespace


vacuum

The active launch campaign for the 11th OneWeb mission began in Vostochny on August 11, 2021, with the installation of the Fregat upper stage in its processing rig. Click to enlarge. Credit: Roskosmos


vacuum

The 11th cluster of OneWeb satellites is being prepared for integration with the Fregat upper stage on Oct. 5, 2021. Click to enlarge. Credit: Roskosmos


vacuum

A Soyuz rocket with the 11th cluster of OneWeb satellites is leaving the assembly building on its way to the launch pad in Vostochny on Oct. 11, 2021. Click to enlarge. Credit: Roskosmos


vacuum

A Soyuz rocket with the 11th cluster of OneWeb satellites arrives at the launch pad in Vostochny. Click to enlarge. Credit: Roskosmos


stage1

Separation of first-stage boosters as seen by an onboard camera during the 11th OneWeb launch. Credit: Roskosmos


fairing

fairing

The separation of payload fairing at an altitude of around 115 kilometers as seen by onboard cameras during the 11th OneWeb launch. Credit: Roskosmos


stage2

stage

The separation of the tail section of the third stage at an altitude of around 151 kilometers as seen by onboard cameras during the 11th OneWeb launch. Credit: Roskosmos