Fuel Bubbles May Have Tripped Sensors in Delta 4-Heavy Launch

Published: Jan 19, 2005
Source: www.space.com



CAPE CANAVERAL, Fla. - Investigators are theorizing that the flow of super-cold liquid oxygen in the three core boosters of Boeing's first Delta 4-Heavy rocket could have been disturbed, creating "bubbles" that tricked internal sensors into thinking the motors were out of fuel and causing them to command a premature engine shutdown, the Air Force said Friday.

The heavy-lift rocket, topped with a instrumented satellite mockup, was launched from Cape Canaveral December 21 on a test flight for the U.S. military. The mission's goal was demonstrating the vehicle's capabilities and identifying any problems before actual national security payloads are entrusted to the rocket.

The Delta 4-Heavy features three Common Booster Cores (CBCs) strapped together to provide 1.9-million pounds of thrust at liftoff. The Rocketdyne RS-68 main engine on each booster consumes liquid hydrogen and liquid oxygen.continue..