The OSPSLV rocket during pathfinder exercises in 1999 at Vandenberg Air Force Base in California. Photo: Spaceport Systems International

A converted U.S. Air Force Minuteman 2 missile stands poised on a California launch pad for liftoff this week after workers solved problems that kept the booster grounded for a month.

The rocket was reassembled last Thursday, clearing the way for liftoff from the Commercial Launch Facility at Vandenberg Air Force Base on Saturday at 0254 GMT (9:54 p.m. EST Friday).

The so-called Orbital Suborbital Program Space Launch Vehicle had been scheduled for its maiden flight in early December, but a pair of technical troubles surfaced during a routine mission dress rehearsal.

During the test, the onboard C-band transponder and the Modular Avionics Control Hardware, or MACH, failed to work properly. The transponder is used to track the rocket during launch and the MACH controls telemetry, power and ordnance commands on the vehicle.

To fix the problems, the rocket's top half -- the third and fourth stages along with its attached satellite payloads enclosed within the protective nose cone -- were removed and hauled to a processing building.

Both units are located in the rocket's avionics section between the fourth stage and satellites, an area that cannot be accessed at the launch pad.

Once in the hangar, workers were able to replace the C-band beacon and fix the MACH computer with a software change, said U.S. Air Force spokeswoman Lt. Colleen Lehne.

The OSPSLV rocket, also known as Minotaur, features the first and second stages of a Minuteman 2 Intercontinental Ballistic Missile. The third and fourth stages are from Orbital Sciences' air-launched Pegasus rocket.

This upcoming launch will attempt to prove the combination rocket's capability to place satellites into space by using leftover Minuteman 2 missile stages. There are currently 350 Minuteman 2 missiles in storage, the U.S. Air Force says.

The JAWSAT payload seen attached to the OSPSLV rocket before the fairing was installed. Photo: Spaceport Systems International

The inaugural passenger is the Joint Air Force Academy-Weber State University multi-payload adapter called JAWSAT.

JAWSAT will haul four separate microsatellites into orbit and then release them.

The first to separate will be Arizona State University's ASUSAT, followed by the U.S. Air Force Research Laboratory's Optical Calibration Sphere Experiment, Stanford University's OPAL satellite and finally the U.S. Air Force Academy's FalconSat.

Later in the launch, JAWSAT will be jettisoned from the rocket's fourth stage.

JAWSAT will circle the Earth with two permanently attached experiments. They are the Plasma Experiment Satellite sponsored by NASA's Marshall Space Flight Center and Weber State University's Attitude Controlled Platform.