Motorola's planned 66-satellite fleet of Iridium worldwide mobile communications satellites were all in orbit on 17 May after the launch of five satellites on a Boeing Delta II from Vandenberg AFB, California.

In all, 72 Lockheed Martin-built satellites in the $5 billion system have now been launched in a year on nine Delta IIs, three Russian K Protons and two Chinese Long March 2C/SDs.

Five satellites are not operational, however, and unconfirmed reports indicate that more are suffering momentum wheel attitude control system and other problems.

Six in-orbit spares are planned to be available at all times. Five more craft will therefore be required to be launched to maintain the system, which is to become operational officially in September.

Two craft are due for a Long March 2C/SD launch in July and 14 more are contracted for seven Long March launches to 2000. The Boeing Delta II will also launch in-orbit spares.

Source: Flight International