Washington – May 10, 1999 – The Air Force team investigating last month’s Titan IVB/DSP launch failure announced Thursday the two stages of the solid fueled Inertial Upper Stage rocket hung up during separation, dragging the second stage behind the rocket and payload during its second stage firing. “In effect, the data shows the vehicle and satellite tumbling in their transfer orbit,” the Air Force said Thursday.
Normally, the two stage solid rocket motors burn in sequence, and the first stage drops away as the second stage prepares to ignite. A compressible nozzle on stage 2 drops down as the first unit is discarded.
But while two of the first stage separation break wires indicated staging, one other connector continued to carry elecrtical signals, indicating that the stages were still partially attached.
As a result, the drop nozzle only partially extended during the second stage firing. “The two extenders did not indicate full extension until after SRM no.2 had fired,” the Air Force report said.
The control system failed to properly orient the tumbling unit, which wound up in a highly elliptical Earth orbit. The Air Force said its investigation was continuing into the launch failure. The IUS is built for the Lockheed Martin Titan IVB by the Boeing Company, builder of the Delta III launch vehicle.
Titan Report From Spacer.Com
