Arianespace, Starsem launches new batch of OneWeb satellites

by Tyler Gray

On Saturday, Arianespace – in conjunction with its Starsem affiliate – launched a Soyuz 2.1b/Fregat-M rocket with 34 OneWeb Internet satellites to low Earth orbit. Liftoff from Site No. 31/6 at the Baikonur Cosmodrome in Kazakhstan occurred at 1:06 pm EDT (17:06 UTC).

The launch of this mission saw the continued use of the Baikonur Cosmodrome for Arianespace, which normally conducts launches from the Guiana Space Centre in Kourou, French Guiana.

The flight was conducted under a commercial launch agreement held by Arianespace through shareholding in an affiliate named Starsem – a joint European-Russian company that is responsible for the commercial launch procurement of Soyuz vehicles for the Russian Space Agency, Roscosmos.

This mission was the 51st flight of a Soyuz rocket under commercial services for Arianespace and Starsem, as well as the 28th commercial Soyuz launch from the Baikonur Cosmodrome.

This was also the third OneWeb flight, and the third to be launched by Arianespace.

Two OneWeb flights have been conducted ahead of this launch, with six satellites being launched from the Guiana Space Centre in February 2019 and 34 additional satellites having launched from Baikonur on February 6, 2020. These two launches began construction of the planned initial 650 satellite constellation (though licensing permits allow that number to increase to 1,972 satellites if customer usage demands as such).

This latest launch of an additional 34 satellites increases the total number of OneWeb satellites in orbit to 74.

OneWeb’s mission is to deliver global communications capabilities through a “next-generation satellite constellation that will bring seamless connectivity to everyone, everywhere.”

To accomplish this, OneWeb is building a network composed of satellites in low Earth orbit that will provide high-speed, low latency services to a wide range of customers in business sectors such as aeronautics, maritime, backhaul services, community Wi-Fi, emergency response services and more.

Photo of 34 OneWeb satellites attached to the payload dispenser – credit: OneWeb

Once deployed, the OneWeb constellation will enable user terminals that are capable of offering 3G, LTE, 5G, and Wi-Fi coverage, thereby providing high-speed Internet access to users around the world via sea, air, and land.

The operational constellation will permit a download speed of 50 megabytes per second, which is equivalent to about twice the speed of public Wi-Fi and hotspot locations in both the United States and Canada.

The launch mass for Saturday’s mission was 5,015 kilograms (11,056 pounds), with each of the 34 OneWeb satellites weighing in at 147.5 kilograms (325 pounds). The satellites will be lofted into near-polar orbits of 87.4 degrees of inclination, with an orbital altitude of 1,200 kilometers.

All 34 satellites were manufactured at OneWeb’s facility in Florida, just outside the secured perimeter of the Kennedy Space Center and Cape Canaveral Air Force Station. Each satellite features a plasmic propulsion system, along with a series of lithium-ion batteries and two solar arrays to provide power and recharge capabilities.

Artistic render of a OneWeb satellite in orbit – Credit: OneWeb

The satellites also contain two TTC omnidirectional antennas, two Ku-band antennas, and two Ka-band antennas.

The 34 OneWeb satellites were launched on a Soyuz 2.1b rocket with a Fregat-M upper stage. The Soyuz 2.1b first flew in December 2006 and has enjoyed a successful career to date with 50 launches and only 2 failures.

At liftoff, the Soyuz 2.1b utilized the power of its four side-mounted liquid fueled boosters in tandem with the first stage engine.

The four boosters are powered by the RD-107A engine, which produces a total of 3,357.92 kilonewtons (754,890.4 lbf) of thrust at liftoff. The RD-108A engine on the first stage produces 792.41 kilonewtons (178,140.8 lbf) of thrust, increasing the total amount of thrust at liftoff to 4,150.33 kilonewtons (933,031.3 lbf).

As the Soyuz 2.1b lifted off and continued its ascent to space, the booster engines and the Blok-A engine began to ramp up so as to provide a total thrust of 5,001.58 kilonewtons (1,124,399.9 lbf).

At a minute and 58 seconds into the flight, the four boosters separated from the Blok-A first stage in a cross pattern commonly referred to as the “Korolev cross”.

At the T+4 minute 48 second mark, hot staging of the Blok-A and Blok I (second) stages occurred. Hot staging is a staging technique in which the engines on the upper stage ignite shortly before the booster engines shut down, with stage separation occurring at engine cutoff. This is done to simplify the staging process.

The payload fairing was jettisoned shortly after hot staging has occurred. This exposed the 34 OneWeb satellites to the vacuum of space.

The Blok I second stage engine shut down at the T+8 minute and 45 second mark, with Fregat-M upper stage separation occurring 38 seconds afterward.

The engine on the Fregat-M ignited at 10 minutes and 23 seconds into the flight to perform a 4 minute and 11 second burn to place the vehicle and payload into a parking orbit.

At 1 hour 6 minutes and 45 seconds after liftoff, the Fregat-M engine ignited once again for a 34-second burn to place the vehicle into the proper orbit for separation of the first two OneWeb satellites.

Deployment of these first two satellites occurred at the T+1 hour 11 minute 40 second mark, with a 15-second burn of the Fregat-M engine following shortly after. Four more OneWeb satellites separated from the upper stage at 1 hour 30 minutes 50 seconds after liftoff.

This process of a short Fregat-M burn followed by the separation of four satellites continued until about 3 hours and 45 minutes after launch, at which point the final four OneWeb satellites were deployed.

After this, Fregat-M will continued coast in orbit until the T+5 hour 5 minute 55 second mark, at which point it ignited its engine for a final deorbit burn.

The Fregat-M upper stage and payload canister reentered the Earth’s atmosphere shortly afterward and be destroyed, thus completing the mission.

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