The Delta 4 rocket during nighttime fueling demonstration at launch pad 37B. Photo: Boeing

The debut launch of Boeing's Delta 4 rocket has been delayed almost a month while ground software designed to automate the final minutes of the countdown is debugged.

Originally scheduled for October 9, the company has picked November 3 as the new launch date. The 64-minute window will extend from 5:34 to 6:38 p.m. EST (2234-2338 GMT) for liftoff from Cape Canaveral's Complex 37B carrying a communications spacecraft for Paris-based Eutelsat.

With four fueling tests successfully completed in the last month, the Boeing launch team turned its attention to the first of two full-up countdown dress rehearsals to simulate the activities to occur in the hours prior to liftoff.

After some initial trouble, the first rehearsal was finished on August 30, verifying procedures, fully fueling the two-stage rocket, performing the pre-launch conditioning of the RS-68 main engine, validating ground support equipment and certifying the launch crew.

"We did T-5 (minutes) and counting and we walked through that all the way down to T-0, pulling alarms out and validating what we expected to see there. It was actually very clean. We counted down four times with planned holds as part of crew certification and then you recycle back," Delta 4 Launch Director Joy Bryant said in an interview Friday.

But one goal not completed was proving out the software that automates some of the chores during the final five minutes of the countdown, which is aimed at easing the launch team's workload. Bugs in the software are to blame.

"This is a subset piece of software that allows us to do automation," Bryant explained. "It is a predetermined list of instructions that would be sent to the vehicle in the same sequence that the console operators would send to the vehicle, it is just automated. So you would push a single button which would then execute three sets of instructions vs. the operator making each of those commands individually."

"The controlling software has already been validated and this just an enhancement," Bryant added.

Launch team members on console during an earlier fueling test. Photo: Boeing

One such job the automation software would handle is topping off and securing the rocket's fuel tanks.

"We would like for that to go on in the background and have the console operator be performing other functions. So we can do it (manually), but I don't want to do those things if we can go automate it."

Bryant says fixing the software shouldn't be too complex. Troubleshooting to find the glitch is underway, to be followed by a fueling demonstration test Friday to run the software through its paces.

"We have been doing some dry runs on the software that runs the automation. We are going to do a tanking test...We will do that Friday after a Wednesday readiness review to say 'OK, yes, here is what we found in our debugging of the automation software and here is how we integrated it with the rest of the ground systems.'

"Now that we have done the dry runs, we just have to do the tanking test to say 'yep, that's got all the issues resolved.' Can something jump up and surprise us? Certainly, but I don't think it is overly complicated."

Assuming Friday's test is successful, thorough data reviews are planned in preparation for the second full countdown dress rehearsal that will culminate with ignition of the rocket's liquid-fueled main engine. The test is called a Flight Readiness Firing, or FRF.

The firing is designed to ensure all the computer software, rocket and ground systems will work together as the countdown goes through the final seconds.

"I would expect FRF to be towards the end of the month. We are looking at the 24th, 25th or 26th, depending on range availability. We will have a crisp sequence of reviews and walkthroughs leading up to FRF."

The FRF will mark the conclusion of the "pathfinder" events prior to the inaugural Delta 4 flight. The rocket has been at launch pad 37B since April 30 for the long series of tests, exercises and rehearsals to pave the way for the inaugural flight.

Once the FRF is performed, focus then shifts to the work to ready for launch, including attachment of the satellite cargo to the rocket. The payload is a European commercial communications satellite for operator Eutelsat. It arrived in Florida last Thursday to undergo final pre-launch checks and fueling.

Bryant says the Delta 4 team is upbeat despite this most recent delay.

"The mood is actually very good. When you are able to come out of a major milestone test with one open item and you have a plan forward, the team is actually very excited.

"We have adjusted the schedule, added the additional tanking test to make sure we have all the automation, and we have put additional time between that and FRF for that readiness review (to) get the community to sit down and look at everything associated with FRF. So the mood is very good."

The Delta 4 was developed by Boeing as part of the U.S. Air Force's Evolved Expendable Launch Vehicle program to create next-generation American rockets for affordable and reliable access to space.

The other EELV launcher -- Lockheed Martin's Atlas 5 -- successfully flew its maiden voyage on August 21.