With its West Coast pad already built, Boeing is in the midst of a multi-month test campaign of the Delta 4 rocket and Vandenberg launch complex in preparation for a maiden blastoff late this year carrying a top-secret spy satellite cargo.

The Vandenberg home of Delta 4 -- the massive Space Launch Complex 6 pad and (behind) the Horizontal Integration Facility. Credit: Boeing

The rocket's two stages were joined together inside the new Horizontal Integration Facility hangar at Space Launch Complex 6 last year. The assembled vehicle was transported on its side to the launch pad and erected upright in late-October for the start of thorough checks and simulations.

"It is on the pad and we doing that combined launch pad/launch vehicle integration testing," Dan Collins, Boeing's vice president and general manager for Delta programs, said in an interview last week. "We are very happy with the results we've had to date."

The launch crews also have conducted a pathfinder program to practice handling the National Reconnaissance Office payload to fly aboard the first West Coast Delta 4 rocket.

"That was a very successful risk mitigation effort that went on in the November time period last year to ensure we had all of the processes and procedures in place to handle the first payload when it comes out."

Electrical testing will be finished in the coming weeks, allowing engineers to turn their attention to propellant exercises in which the rocket will be fueled. The activities will culminate with a launch day dress rehearsal this spring.

"The hardware is working well, the team is motivated and, I think, enjoying the effort and the task they have in front of them," Collins said. "(We are) getting good feedback from the customer -- they are pleased with the progress being made. So in general, it looks to be a real good situation."

SLC 6 was overhauled from its shuttle days to support Delta 4. Credit: Boeing

"Things have been very nominal, I think, mainly due to the fact we have designed the system on the West Coast as a duplicate, as much as possible, to the East Coast system. We are able to apply a whole lot of the lessons learned," Collins said.

The Space Launch Complex 37B pad at Cape Canaveral Air Force Station is the Florida home for Delta 4. That site, which has successfully supported the first three Delta 4 missions, is similar in concept with Vandenberg's SLC 6 pad.

"Whenever you go into a non-recurring design and then you actually start utilizing that design, you learn a lot the first couple of times you use it. We did learn a whole lot down at the Cape. But we made sure that we took the time on the West Coast to incorporate the design changes into the West Coast before we built it.

"What we built out of the gate (at Vandenberg) was the design that already had the additional knowledge from activating the East Coast. Obviously, it is the smart thing to do, but I think it is the big reason why we are on schedule and have been very successful in the activation on SLC 6."

The SLC 6 facility -- commonly called "Slick Six" -- was first constructed in the 1960s for the Air Force's Manned Orbiting Laboratory. It was rebuilt in the 1980s for space shuttle missions. But both projects were cancelled before any launches occurred. The site was, however, used for a handful of flights by Lockheed Martin's small Athena booster in the 1990s.

Major renovations to transform the existing shuttle facilities to support the Delta 4 program have been ongoing for a couple of years, installing a large erector arm to hoist the assembled rockets upright, stripping down the umbilical tower to add swing arms, modifications to the service tower and building the Horizontal Integration Facility nearby.

Space Launch Complex 6 overlooks the Pacific Ocean. Credit: Boeing

Launch of the first Delta 4 from Vandenberg is scheduled for this December.

"We will have the launch site ready well in advance of that. So the first launch is going to be paced by the availability of the payload," Collins said.

Readiness of the classified cargo has been delayed repeatedly, pushing back the launch nearly two years from the originally envisioned schedule.

It is not yet clear if the Delta 4 will remain on the pad from now through launch. It could be returned to the Horizontal Integration Facility hangar, depending on the official liftoff date chosen.

"That is a question that we and the customer are both looking at together right now," Collins said. "We want to work hard and get to the first Wet Dress Rehearsal (this spring) because there is a major risk reduction involved in having completed one Wet Dress Rehearsal. You've really run the team through its paces, and you will know that you've got the bugs worked out and you need to tune things or if there was an issue of greater importance that you need to deal with.

"So as we accomplish that milestone, we are going to sit with the customer and look at all of the parameters and determine what the best path is between first Wet Dress Rehearsal and first launch."

Boeing has two West Coast Delta 4 missions scheduled in 2005 -- another NRO cargo and an Air Force polar-orbiting weather satellite.