PARIS — The first four O3b Ka-band mobile broadband satellites have arrived at Europe’s Guiana Space Center spaceport to prepare for a launch that, as expected, has been postponed by about a month, to June 24, O3b and the Arianespace launch consortium said April 25.

The delay was caused by an 11th-hour hardware replacement needed for the European Space Agency’s ATV-4 cargo carrier, whose April launch to the international space station was thus rescheduled for the first week of June.

The launch teams at the spaceport, on the northeast coast of South America near Kourou, French Guiana, need about three weeks following an ATV launch to rearrange the ground tracking stations that follow the vehicles used at the spaceport — the heavy-lift Ariane 5, which carries the 20,000-kilogram ATV; the medium-lift Soyuz, which will launch the four 700-kilogram O3b satellites; and the Vega small-satellite launcher, whose second flight is now scheduled for May 3.

A second batch of four O3b satellites is scheduled for launch aboard a European Soyuz in September, with a third set for 2014. O3b Networks, which is based in Britain’s Channel Islands, and its lead sponsor, satellite fleet operator SES of Luxembourg, have said that an early success of the project would be followed by an order for more satellites to be launched into the unusual medium Earth equatorial orbit some 8,070 kilometers over the equator.

Peter B. de Selding was the Paris Bureau Chief for SpaceNews.