CAPE CANAVERAL, Fla. -- Technical concerns within NASA's shuttle and Boeing's Delta 4 programs, along with Eastern Range scheduling issues, have conspired to delay a pair of upcoming launches from Florida's Space Coast.
The plan now is for Boeing's inaugural Delta 4 rocket to fly on Tuesday, followed by launch of shuttle Endeavour's assembly and crew rotation mission to the International Space Station next Friday, Nov. 22.
Boeing had hoped to launch on Saturday, even though an approaching cold front had promised severe weather and a 90 percent chance of stopping the shot.
But last-minute concerns about the Delta 4's RL-10 upper stage rocket engine forced the aerospace giant to delay the high-profile launch until Tuesday.
An ongoing study of cracks found in an RL-10 engine recently tested at Pratt & Whitney in south Florida revealed some new information that required another review of the hardware now installed on the Delta 4 rocket sitting at complex 37, said Dan Collins, Boeing's vice president and Delta program manager.
"The reason for waiting was to make sure that my engineers had completed what they needed to do and felt comfortable in order to go towards launch," Collins said. "I'm very confident that over the weekend we'll be able to reach full understanding."
A launch readiness review is set for Monday and if that goes well, the Delta 4 will lift off between 5:39 and 6:49 p.m. EST (2239 and 2349 GMT) Tuesday.Air Force meteorologists predict a 90 percent chance of acceptable weather conditions on Tuesday and Wednesday -- the two days Boeing now has the Air Force-managed Eastern Range booked for.
Across the Banana River at the Kennedy Space Center, shuttle program managers are setting up for a Friday launch attempt to give the Air Force-managed Eastern Range the 48 hours of required time to reconfigure their systems to handle the different types of vehicles.
But there are some problems.
"We continue to have two open issues and we're in different stages of converging to a solution on both issues," shuttle program manager Ron Dittemore said late Friday.
The first issue is fall out from the reason why Endeavour's initial launch attempt was scrubbed last weekend.
A leaking gaseous oxygen line was found inside Endeavour's midbody, under the cargo bay, and had to be replaced. That work is just about finished, but managers still are trying to determine exactly why the flexible hose failed and want to make sure the problem does not exist on similar hardware within the rest of the orbiter fleet.
The second issue has to do with the shuttle's robot arm, which was damaged during the inspection and repair work on the oxygen line when a work platform rubbed hard against it near the arm's shoulder joint. Human error is to blame for the accident, Dittemore said.
A spotter charged with the responsibility of calling a stop to the platform's movement if it came too close to any flight hardware was momentarily distracted, possibly because the person was looking to move to a different vantage point, Dittemore said.
As a result, a section of the arm's thermal protection blanket and part of a honeycomb-shaped outer layer was damaged and later cut away.
Ultrasound inspections of the carbon composite material that makes up the "bone" of the arm revealed some "bruising" or delamination of the material, and engineers now are trying to understand if that damage is severe enough to have compromised the structural integrity of the arm.
"We do not have data that says the arm has been impacted to the point of where we cannot use it or cannot fly it, so we shouldn't draw that conclusion yet," Dittemore said.
As a precaution, officials are beginning to assemble plans just in case the Canadian-built arm is ruined.
Dittemore said the early rough draft of a plan would call for the removal of the robot arm while Endeavour is at the pad and flying the station assembly mission without the arm.
Setting up, training and executing that plan could delay Endeavour's launch another two to three weeks or so -- or roughly half of the five to six weeks it would take to roll Endeavour back off the launch pad, remove it from the external tank, tow it to its hangar, remove and replace the robot arm, then repeat the process of getting back out to the pad and get ready for launch.
Dittemore said engineers will work through the weekend studying both concerns and then present him with results of their work on Monday, and following that he should have a better handle on whether or not Endeavour will be ready to fly by Friday.
"Monday's going to be a big day for us," Dittemore said.
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