Launch Time

The United Launch Alliance announced this afternoon that it has identified the problem experienced by its Evolved Expendable Launch Vehicle rocket booster during an October Air Force launch, and ULA says it is confident there is no risk that a launch planned for Tuesday will go awry.

In a statement from ULA spokeswoman Jessica Rye, issued after 5 p.m. today, the company said a fuel leak in the upper-stage engine of the Delta IV rocket booster used in October was to blame for the lower-than-expected thrust experienced during launch. The Air Force and ULA plan to send the service's X-37B spaceplane, also known as OTV-3, into orbit on Tuesday using an Atlas V booster, which uses a variant of the same RL-10 upper-stage engine. All "crossover" risks, though, have been taken care of, Rye said.

"The ULA investigation has concluded that a fuel leak occurred in a specific area of the interior of the thrust chamber, and that this leak started during the first engine start sequence," according to the statement. "Although the investigation into the flight data anomaly continues, all credible crossover implications from the Delta anomaly for the OTV-3 Atlas vehicle and engine system have been thoroughly addressed and mitigated, culminating in the flight clearance decision for the OTV-3 launch."

Inside the Air Force attended the Oct. 4 launch of a Global Positioning System satellite from Cape Canaveral Air Force Station, FL. The flawed launch triggered a formal accident investigation board from Air Force Space Command, only the second space-driven AIB in the last decade, as ITAF reported in the weeks following the event.