File photo of a Delta 2 rocket sitting atop pad 17B before launching for Globalstar. Photo: Boeing

Preparations are reaching the pinnacle for the first Boeing Delta rocket launch of 2000, a $110 million mission dedicated to completing Globalstar's space-based cellular telephone system.

Scheduled for liftoff Tuesday afternoon, the Delta 2 rocket will carry a cluster of four Globalstar satellites into low-Earth orbit.

The Boeing launch team will have a 30-minute window to get the Delta airborne beginning at 3:54 p.m. EST (2054 GMT).

The launch was delayed two days so the rocket's guidance computer, called RIFCA for the Redundant Inertial Flight Control Assembly, could be repaired. A similar box failed a pre-flight test recently and prompted workers to tighten screws inside the flight unit.

This 276th Delta mission will feature a 7420-configuration vehicle with two stages and four strap-on solid rocket motors.

One of new satellites will serve as the 48th and final spacecraft in Globalstar's constellation. The other three birds and one launched earlier will act as orbiting spares.

Globalstar began its commercial service late last year. The system is designed to reach most of the world's population to provide voice, data and paging services.

Workers transported the four satellites from a processing facility to Cape Canaveral Air Force Station's launch pad 17B on January 28. The satellites, mounted to a special dispensing structure, were then attached to the rocket's second stage.

File photo of four Globalstar satellites attached to their dispenser at the launch pad. Photo: Boeing

Testing between the craft and booster followed over the next few days. The rocket's 10-foot diameter nose cone was installed on Saturday to protect the payload during launch.

The mission will mark the seventh time a Delta rocket has been used in Globalstar's satellite deployment campaign since February 1998.

The previous six launches each carried four satellites, amounting to half the Globalstar constellation. Four of those launches occurred last summer during an intense and record-setting 68-day period.

Six other Globalstar launches were aboard Russian-built Soyuz rockets, which also deployed four satellites each.

Although the upcoming Delta launch will bring Globalstar's satellite deployment effort to a close, additional spacecraft will be sent aloft periodically over the next few years to maintain the constellation's health.

For Boeing, Tuesday's launch will be the first of 16 planned in 2000 from Cape Canaveral and Vandenberg Air Force Base in California. Those launches will include 11 Delta 2 rockets and five of the new Delta 3 booster.