ROME — Europe’s fourth ATV cargo carrier has been cleared for a June 5 launch to the international space station, a date that will complicate life for startup satellite broadband provider O3b Networks, whose first launch has been scheduled to occur in late May from the same French Guiana spaceport.

The 20,000-kilogram ATV-4 missed its original April launch date when a glitch was found in an avionics box during testingat the Guiana Space Center, located on the northeast coast of South America.

ATV’s planned Ariane 5 launch was moved to an undetermined date.

Meanwhile, O3b, based in Britain’s Channel Islands, has been hurrying final testing of the first four of its eight satellites planned for launch this year aboard two Europeanized Soyuz rockets.

Ariane 5 and the European Soyuz, as well as the Vega small-satellite launcher, use the same down-range radars and tracking gear. After the launch of one of them, the tracking radars must be repositioned to prepare for the launch of one of the other two vehicles. The repositioning can take between two and three weeks.

Brian Holz, O3b’s chief technical officer, said here March 27 that the company has asked its satellite manufacturer, Thales Alenia Space of France and Italy, to work two-shift days — and occasionally round the clock, seven days a week — to complete the first O3b satellites as soon as possible to ship to the spaceport and secure an early Soyuz flight.

Holz said the first four 700-kilogram O3b satellites are now on track to be shipped by Antonov aircraft to the launch base April 9, arriving April 10. Testing at the site could have all four ready for placement in a Soyuz rocket May 26 or May 27, he said.

But that date is now running up against the ATV timetable. Alberto Novelli, ATV mission manager at the 20-nation European Space Agency (ESA), said in a March 27 interview that the Arianespace launch consortium, which manages the French Guiana manifest, confirmed a June 5 launch date aboard an Ariane 5.

Reconfiguring the down-range radars following an Ariane 5 launch on June 5 would likely push O3b’s launch to late June.

Holz said O3b is aware of the complications brought by the ATV mission, which must not only clear a launch date with Arianespace but also reserve a station docking window with NASA and the other space station partners.

Holz said Thales Alenia Space’s O3b engineering teams have sacrificed Christmas holidays and are working through Easter as well — neither is an obvious concession in France and Italy — to position the O3b satellites for as early a launch date as possible.

Whether that same thinking prevails at the Guiana Space Center, which in addition to Easter is coming up on a month of May that is traditionally full of French holidays, is not clear.

Holz said he is holding out some hope that the ATV launch date could be pushed out a few days, leaving O3b time to launch in late May and then give the necessary 15 to 20 days to prepare for a mid-June ATV launch. He said that, as a startup company, O3b has a revenue stream that is directly dependent on the launch date.

European government and industry officials have long said it is not easy juggling the demands of commercial and government launch customers at the Guiana Space Center. Commercial customers have long suspected that not all customers are created equal, especially in the case of major government campaigns such as the ATV.

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