A Russian Soyuz rocket is poised for lift off Tuesday from Kazakhstan with another 34 internet spacecraft for OneWeb, the company’s 10th launch since deployment of the satellite network began in 2019.

Ground crews at the Baikonur Cosmodrome rolled the Soyuz-2.1b rocket to the Site 31 launch complex Saturday. After lifting the rocket vertical, teams moved gantry arms into position around the launcher to complete final pre-flight inspections and other preparations for liftoff.

Launch is set for 2:07:19 p.m. EDT (18:07:19 GMT) Tuesday to carry OneWeb’s next 34 satellites into orbit. A successful launch would expand OneWeb’s fleet to 322 satellites, second in size only to SpaceX’s constellation of Starlink internet satellites.

OneWeb, backed by the British government and the Indian telecom company Bharti Global, plans to launch 648 small internet satellites, including spares, to provide broadband connectivity to customers around the world.

With 322 satellites, OneWeb will near the halfway mark of its fleet deployment.

OneWeb’s first satellites launched in February 2019 on a Soyuz rocket from the European-run spaceport in Kourou, French Guiana. Soyuz rockets have launched eight more missions with groups of 34 or 36 OneWeb satellites from Baikonur and the Vostochny Cosmodrome in Russia’s Far East.

Each OneWeb satellite is about the side of a mini-fridge. The spacecraft are built by OneWeb Satellites, a joint venture between OneWeb and Airbus, in a factory just outside the gate of NASA’s Kennedy Space Center in Florida.

The satellites, each fitted with a xenon-fueled ion thruster, beam broadband internet signals to users on the ground, at sea, or in the air, providing high-speed, low-latency connectivity for consumers, large companies, and governments. OneWeb is competing with SpaceX’s Starlink network, along with planned internet constellations from other companies.

So far, pace of launches for the Starlink network have outrun efforts by SpaceX’s competitors. SpaceX launched another cluster of 51 Starlink satellites Monday night from Vandenberg Space Force Base, kicking off the second phase of the company’s Starlink deployment.

SpaceX has authorization from the Federal Communications Commission to eventually launch and operate 12,000 Starlink satellites. The company has launched 1,791 Starlink satellites to date.

The OneWeb satellites fly at higher altitudes than the Starlink spacecraft. The difference in architecture means OneWeb can reach global internet coverage with 648 satellites, a significantly smaller constellation than Starlink.

Amazon is planning its own commercial satellite internet constellation, but hasn’t started launching. China is also developing a broadband network that could include thousands of small satellites.

A Soyuz launch in July gave OneWeb enough spacecraft to provide internet services to customers north of 50 degrees latitude, once the satellites move into their proper orbital planes and complete testing. Another 34 OneWeb satellites launched Aug. 21 from Baikonur.

OneWeb filed for bankruptcy in March 2020 after failing to secure enough funding to continue building and launching satellites. The reorganized company emerged from bankruptcy last year under the ownership of Bharti Global and the UK government.

OneWeb announced Aug. 12 a $300 million equity investment from Hanwha, a South Korean tech and manufacturing firm. The funding brings the total equity investment in OneWeb since November 2020 to $2.7 billion, the company said.

Neil Masterson, CEO of OneWeb, said last month that the company has enough funding to complete its 648-satellite constellation by next year.

Masterson sees strong demand for internet connectivity, a market that is driving billions of dollars in private investment in networks like OneWeb and Starlink.

“We don’t know yet quite how big that demand is, and we don’t know how many participants in the marketplace that will support, but I think it’s a lot bigger than people think,” Masterson said in a panel discussion at the Space Symposium.

“There are millions and billions of people that do not have access to decent internet,” said Gwynne Shotwell, SpaceX’s president and chief operating officer. “So that’s a pretty big market. I am not worried about the number of organizations that are interested in doing this. I’m interested and concerned about their sustainability when it comes to the space environment.”

The Soyuz rocket launching Tuesday will blast off with more than 900,000 pounds from 32 engine nozzles, guiding the launcher toward the north from Baikonur. Within two minutes, four liquid-fueled first stage boosters will shut down and jettison, and the Soyuz core stage will switch off and separate nearly five minutes after liftoff.

Moments after the third stage engine ignites, the Soyuz willl shed its clamshell-like aerodynamic payload shroud. The third stage will deploy a Fregat upper stage on a preliminary suborbital trajectory more nine minutes into the mission, completing the role of the Soyuz rocket for the mission.

The main engine of the Fregat upper stage will ignite two times to place the 34 OneWeb satellites into a targeted polar orbit roughly 280 miles (450 kilometers) above Earth, with an inclination of 87.4 degrees to the equator.

Then begins a series of deployments to release the 34 OneWeb satellites from a composite dispenser, or connecting interface, made by RUAG Space in Sweden.

First, two of the 325-pound (147.5-kilogram) satellites will separate from the top of the cluster. The remaining 32 spacecraft will separate in groups of four at intervals of approximately 20 minutes, with maneuvers by the Fregat’s smaller attitude control thrusters in between to ensure the satellites did not collide.

The satellite separation events will largely occur when the Fregat is flying outside the range of ground tracking stations, so confirmation of some of the spacecraft deployment milestones will be delayed.

The last group of OneWeb satellites will release from the Fregat’s dispenser around 3 hours, 45 minutes into the mission.

The OneWeb satellites will use their on-board xenon propulsion systems to raise their altitude to enter the company’s operational constellation 745 miles (1,200 kilometers) above Earth.

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