Four broadband communications satellites for O3b Networks, a company based in Britain's Channel Islands with a mission to link developing countries via high-speed Internet, blasted off from French Guiana on top of a Russian Soyuz rocket Thursday.

The Soyuz rocket blasts off from French Guiana with four satellites for O3b Networks. Credit: ESA/CNES/Arianespace - Photo Optique Video du CSG - JM Guillon

The satellites will fly in a unique orbit 5,000 miles over the equator, reaching customers in a band between 45 degrees north and 45 degrees south latitude, home to most of the world's population.

The spacecraft host Ka-band antennas to broadcast services to customers out of reach of terrestrial broadband networks, boosting data throughput and connection speeds in homes, businesses, schools and hospitals.

O3b's name is short for the "other 3 billion," referencing the approximate number of people without reliable, high-speed Internet connections.

The company sells broadband capacity to national telecom networks, luxury cruise liners and Internet service providers, providing the backbone for widespread connectivity on ships, islands, in remote jungles and in dense urban centers.

Thursday's launch put O3b's second set of four satellites into orbit after an initial launch in June 2013.

Liftoff of the four spacecraft, built by Thales Alenia Space of France and Italy, occurred at 1855:56 GMT (2:55:56 p.m. EDT; 3:55:56 p.m. local time) from the Guiana Space Center, a European-run spaceport on the northern coast of South America.

A Russian Soyuz launcher rocketed east from the space base, arcing over the Atlantic Ocean through mostly cloudy skies.

The three-stage core of the venerable Soyuz rocket, which has flown more than 1,800 times since the 1950s, released a Fregat upper stage and the four O3b satellites into space less than 10 minutes after liftoff.

The Fregat main engine fired four times to inject the satellites into a circular orbit about 7,830 kilometers, or 4,865 miles, above the equator.

Each weighing about 700 kilograms, or 1,543 pounds, the spacecraft separated in pairs from a dispenser mounted on the Fregat upper stage. The announcement of the deployment of the last two satellites triggered a round of applause in the Jupiter control center at the Guiana Space Center.

"Tonight's launch is the second performed by Arianespace for O3b, a little more than one year after the first successful flight that marked O3b's debut," said Stephane Israel, chairman and CEO of Arianespace, the commercial operator of Soyuz missions from French Guiana.

Thursday's launch was the eighth mission of a Soyuz rocket from French Guiana since October 2011, when the workhorse launcher made its first flight from the tropical spaceport.

"O3b is one of more than 40 new satellite operators which have trusted Arianespace to start their business," Israel said in post-launch remarks. "Behind that trust, there is a true recognition of the reliability and availability of our launch systems."

The next Soyuz launch from French Guiana is set for Aug. 21 with two Galileo navigation satellites for the European Commission, which is building a counterpart to the U.S. Air Force Global Positioning System.

"Soyuz remains the reference for satellite constellation deployment -- today with O3b and soon this summer with Galileo," Israel said.

The next launch from the Guiana Space Center is scheduled for July 24, when a heavy-lifting Ariane 5 rocket will send the European Space Agency's fifth and final Automated Transfer Vehicle on a resupply run to the International Space Station.

The four O3b spacecraft mounted on a dispenser before encapsulation by the Soyuz rocket's aerodynamic nose fairing. Credit: ESA/CNES/Arianespace - Photo Optique Video du CSG - JM Guillon

The four satellites launched Thursday will enter service by Sept. 1, according to Steve Collar, CEO of O3b Networks.

Jean-Loïc Galle, president and CEO of Thales Alenia Space, said all four satellites responded to initial commands following separation from the Fregat upper stage.

"I can confirm that we have heard the first cry from your four new babies," Galle told O3b executives gathered at the French Guiana launch base.

Ground controllers plan several days of testing on each spacecraft's primary systems, then they will guide the satellites into a slightly higher orbit to enter O3b's constellation. Officials plan about three weeks of activations and checkout of the Ka-band communications transmitters and antennas.

O3b's second launch was delayed from September 2013 after engineers discovered a problem with the power systems on the satellites launched last summer. Officials shipped the satellites from French Guiana back to their factory in Rome for repairs, and the next launch opportunity in the Soyuz rocket's manifest was not until this summer.

"Those issues really have no impact whatsoever on our customers," Collar said in an interview Thursday. "One of the great benefits of being a constellation is that we will continue to launch satellites into the same orbit, and what we saw on the first four satellites has almost no impact on our business going forward."

But officials were eager to launch another four satellites, which will expand the reach of O3b's broadband service and give the company more robust footing in space.

"It's important because we're a young company, and we're delivering genuinely different services than everyone else," Collar said. "There's no one else that can provide the quality connection -- the fiber-like performance -- that we can deliver, and still retain the flexibility of satellites. For us, it's very important to get the satellites up there, but it's also very important for our customers who have been waiting patiently for the service, and have been for some time."

Collar says customers are pleased with the interim capacity offered on the first four O3b satellites.

"The performance has blown us way, to be honest," Collar said. "We're able to provide more than a gigabit [per second] per beam -- the sorts of throughputs that you only normally associate with fiber. With satellites, you're normally talking about kilobits or megabits [per second]. We're orders of magnitude higher in terms of throughputs."

O3b has launched commercial service with three customers: Telecom Cook Islands, Digicel Papua New Guinea and Timor Telecom of East Timor.

The company has launched trial service on Royal Caribbean's Oasis of the Seas cruise liner, with full commercial service expected by the end of the year, Collar said.

Artist's concept of O3b satellites in orbit. Credit: Thales Alenia Space

"With only four satellites, we have a relatively limited geography that we can actually deploy full commercial service and meet all the service level agreements that we've signed up to with our customers," Collar said. "That all changes with the launch of these next four satellites."

Two more clients in the Democratic Republic of the Congo and Samoa are next to get O3b's high-speed Internet service, according to Collar.

Four more Thales-built O3b satellites will be ready for launch by the end of 2014, Collar said, but they are not scheduled for liftoff until early 2015.

O3b officials are evaluating concepts for O3b's next-generation satellites. The spacecraft fly in a unique, unused orbit not populated with other satellites, leaving plenty of room for growth.

The O3b satellites fly four times closer to Earth than traditional telecom satellites in geosynchronous orbit, a belt 22,300 miles over the equator where a spacecraft's orbit is locked over the same location on Earth, allowing ground antennas to remain pointed at a stable point in the sky.

O3b touts its system as a low-latency, higher-speed alternative to conventional geosynchronous satellites.

"We have 12 satellites initially, but we can grow to more than 100," Collar said. "The future is very bright, and we will only be limited by the market. For the time being, we don't see any stop in the demand for broadband connectivity, so we're going to keep launching satellites and keep deploying services for as long as there is demand."

Collar said he was optimistic O3b would decide on a plan for more satellites by the end of the year.

Follow Stephen Clark on Twitter: @StephenClark1.