The Delta IV L-22 on the pad at Vandenberg Air Force Base. The planned Oct. 3, 2005, launch of the rocket was scrubbed and is expected to take place sometime in 2006. Photo courtesy of Martin Scott, BD Systems.

Launch Facility Profile

Vandenberg Air Force Base

VANDENBERG AIR FORCE BASE, Calif. (2/17/06) -- It was a double-header for the mission assurance teams at Vandenberg AFB.

In the summer of 2005, the Vandenberg Air Force Base launch schedules for upcoming Titan IV and Delta IV rockets were both slipped to October. Suddenly The Aerospace Corporation's Western Range Directorate (WRD) faced the task of having the same team handle mission assurance for both rocket types concurrently.

Joe Wambolt, principal director of the corporation's Western Range Directorate, and Bill Sutton, the Delta IV/Titan operations system director, didn’t have the luxury of time. “Doubling up meant potential conflicts regarding vehicle testing, mission assurance tests, customer briefings and support personnel availability,” Sutton said.

Wambolt met the challenge with an organizational structure that made the most of limited resources. “We decided to fold our Titan program people into the Delta team and come up with a matrixed structure that would give us plenty of skills redundancy,” Wambolt said. The team pulled in additional expertise from the WRD’s Systems Engineering and Flight Systems Integration groups.

Wambolt and Sutton knew the challenges. The two rockets were designed in different eras, using different propellant systems and different hardware for vehicle guidance.

However, Wambolt had confidence in his team. “The two vehicles have similar subsystems and require similar engineering skills," he said. "And we’ve put together a team with knowledge of the Titan and Delta IV inside out.”

The Work

Launch vehicle processing of Titans and Deltas can take six to eight months. Each rocket is complex, “one-up” engineering. The challenge of providing mission assurance can be summed up by the industry definition: What’s 30 stories high, a billion dollars of technology, tons of explosives? A rocket.

“You’re dealing with a controlled explosion so there’s no second chances, no trying it out first,” explained Wambolt. “It’s either go or no go – and that’s why everyone is so cautious. We and the contractor look at every piece of data for that one missed clue.”

When the Delta IV rocket comes in from the factory, it’s delivered to the Horizontal Integration Facility (HIF) at Vandenberg. The cavernous HIF is like a test bench where the 196 feet of booster can be laid out horizontally. Here the rocket system can be put through a battery of tests. The satellite goes to a similar facility, the Integrated Processing Facility (IPF), for testing.

A corporate database of more than 200 tests and procedures (predefined by the manufacturer) are designed to ensure that every subsystem and component performs as expected. “Each technical discipline – such as guidance, electrical, flight programming, propulsion, avionics, tracking, flight safety, etc. – is analyzed by the appropriate responsible engineer for out-of-spec data, out-of-family trends or anomalies,” Sutton said.

The booster and payload are then transported to Vandenberg's Space Launch Complex (SLC)-6, brought vertical, then mated on the launch pad where weeks or months of integrated testing take place. “Both teams come together to make sure all parts work seamlessly,” Wambolt said. “Then we run rehearsals to make sure the people who manage the countdown know what to do, who to talk to, and how they’re supposed to conduct themselves.”

In the final days the WRD team prepares briefings for The Aerospace Corporation's president and CEO, Dr. Bill Ballhaus, and the appropriate management team. Then the Aerospace team and their contractor counterparts brief the Air Force. After this readiness review process, if all of the concerned parties are in agreement, the decision to launch is made.

On the day of launch, each parameter is checked and re-checked. Even in the final seconds the mission can still be scrubbed. “Once final countdown has begun, it’s not feasible to ‘manually’ monitor the massive amount of data and spot an out-of-spec vehicle response during terminal count,” said The Aerospace Corporation's Jess Leyva, senior project engineer. “But specialized test, display, and alarm subsystems (Delta Launch Processing System) can tell us if something is outside of pre-specified limits.”

“The Terminal Count Sequence Logic (TCSR) controls the vehicle from T minus 8.5 seconds through lift-off (T minus 0) by issuing commands and monitoring parameters of various RS-68 engine, booster and launch site elements. At about T minus 5.3 seconds, the booster engine ignites,” Leyva said. “The heavy propellant turbines quickly spin-up using a sudden burst of ground-stored helium. Then the explosive mixture of liquid H2 and O2 get pumped into the engine’s combustion chamber at very high temperature and pressure. The RS-68 engine then builds up to generate 650,000 pounds of thrust, roughly equivalent to the power of three Diablo Canyon nuclear reactors, or 3300 mega-watts,” he said.

By now, Leyva said, the engine thrust exceeds the vehicle weight, so it begins to pull the rocket against its moorings. Yet the computer launch system continues to analyze thrust, pressure and temperature parameters. The launch still can be aborted if a problem is detected.

After T minus 30 milliseconds the Delta Launch Processing System computers inhibit all abort criteria. At this point, there is no turning back. At T minus 0, the rocket lifts off, accelerating the payload to more than 25,000 mph – roughly the escape velocity for a low-Earth orbit. Within 10 minutes the rocket will escape Earth’s grip.

Final Results

During the Delta and Titan launch effort, Aerospace engineers spent months working with their contractor counterparts to ensure every system and subsystem performed as expected. In spite of the challenge of dealing with two concurrent jobs, the organization worked flawlessly.

On Oct. 3, 2005, two days before the planned launch, the decision was made to scrub the launch of the Delta IV L-22. Work by WRD and contractor personnel stopped. Analysis by members of the launch verification team had uncovered a potential problem with fuel slosh in the second stage hydrogen tank. The L-22 spacecraft was de-stacked and stored.

Aerospace continued work on the Titan. On Oct. 19, 2005, the Titan IV B-26 went up without a hitch at 11:05 a.m., blasting a National Reconnaissance Office satellite into polar orbit.

“From our perspective both missions were a success,” Wambolt said. “The Titan – the last Titan ever to fly – went up flawlessly. The Delta didn’t go. But it taught us about a potential mission assurance issue that we’ve been able to proactively fix. And we fully expect to send it up in a matter of months. The system worked perfectly.”

The Aerospace Corporation, with headquarters in El Segundo, Calif., is an independent, nonprofit company that provides objective technical analyses and assessments for national security space programs and selected civil and commercial space programs in the national interest.