The medium Earth orbit constellation designed to bring broadband satellite service to the “other 3 billion” (O3b) customers in the developing world is taking shape above the equator with the June 25 launch of the first four spacecraft on an Arianespace Soyuz flying from the Guiana Space Center on the north coast of South America.

Another set of four satellites is scheduled for launch later this year, and the third and final group of four is set to go up in the first half of next year.

Built by Thales Alenia Space, the O3b satellites weigh 700 kg each, and will orbit above the equator in a repeating orbit 8,062 km up that will present the same satellite to a given ground station every 6 hr. Each satellite generates 1.5 kw of power, driving 12 mobile antennas and 10 Ka-band transponders.

O3b Networks plans to install eight teleports worldwide, with a network operations center in Virginia and a satellite operations center in Luxembourg. Designed with a coverage area that falls between 45 deg. north and south of the equator, the mobile antennas will allow the spacecraft to communicate with special ground receivers that will include tracking antennas capable of following the orbiting satellites, handing off from one to another as they pass overhead.

Ground terminals will use 1.8-meter and 2.4-meter General Dynamics antennas and 4.5-meter and 7.3-meter systems supplied by ViaSat, the company says. Comtech is providing modems tailored to support mobile backhaul while Gilat will supply networking hubs and O3b customer modems.

The Soyuz mission required 2 hr., 22 min., and included four burns of the three-stage rocket’s Fregat upper stage. Liftoff came at 3:27 p.m. EDT (4:27 p.m. local time).