Intelsat is switching satellite launch vehicles.

The 112-nation communications cooperative decided to book the European Ariane rocket to launch three satellites because future commercial payload launches from the U.S. space shuttle are in doubt. Intelsat had originally planned to launch a series of five satellites from the shuttle. The organization’s board of directors approved buying an Ariane launch for the third Intelsat 6 satellite. The first two Intelsats had been scheduled for shuttle delivery to orbit in 1987 and 1988, and arrangements for switching to Ariane had been made previously.