The weapon and its dummy warhead successfully blasted out of an underground silo on north Vandenberg Air Force Base at 1:01 a.m. Thursday, right at the opening of the launch window.

The military tracked the weapon as it traveled roughly 4,200 miles southwest of the base to a target in the central Pacific Ocean.

Thursday's test, like its counterpart on July 21, collected data about how a newer warhead - typically found on the soon-to-be deactivated Peacekeeper missile - performed while riding on the tip of the Minuteman 3.

It was the second of four planned tests for the "safety enhanced re-entry vehicle" program, or SERV, which is one aspect of an Air Force effort to extend the life of the Minuteman weapon fleet.

"Each missile launch is the culmination of a tremendous amount of work preparing and executing a safe and reliable test flight," said Lt. Col. Stephen Davis, 576th Flight Test Squadron commander. "The data we receive from these tests is vital in ensuring a safe, secure and reliable ICBM force."

The 576th is the unit responsible for unarmed intercontinental ballistic missile tests conducted from Vandenberg.

During this year's earlier launch attempts, the 576th was plagued by a string of unrelated troubles that kept missiles in the ground. They included a freak incident in which a plastic environmental cover allowed rain to leak into the silo, and a last-second abort when a computer spotted a problem. One of those routine tests was canceled.

"Our mission isn't necessarily to launch," Davis said. "Our mission is the test the weapon system."

Even without blastoff, the technical glitches allowed the Air Force to collect valuable test data, he added.

While this year has proven extra busy with the two SERV missions, the unit typically handled several launches a year to collect reliability and accuracy data to gauge the health of the fleet of 500 weapons on alert in Wyoming, Montana and North Dakota.

The squadron also has two more test launches that are tentatively set for Sept. 7 and 14.

Members of the 576th performed maintenance activities, including installing the missile and its Vandenberg-unique tracking, telemetry and command-destruct equipment, that are required to collect test data.

Combat missile crews pulling "alert duty" in underground capsules several stories deep underground in Wyoming, Montana and North Dakota only get the chance to turn the key to launch a missile in a time of crisis.

Capt. David Washer was among missileers from Malmstrom AFB, Mont., who were sent to participate in Thursday's test.

"It's quite an honor, obviously," he said. Despite hours of training to do their jobs, missileers don't want to launch an ICBM in anger, hence the name "Glory Trip" for the chance to take part in a test launch and join the elite club of people who have launched a missile.

"They are few and far between," added Capt. Bob Colpitts, who took part in a Glory Trip in 2002 and is now with the 576th at Vandenberg.

Janene Scully can be reached at 739-2214 or janscully@santamariatimes.com.