A Delta 4 rocket was launched from Vandenberg Air Force Base in California, on a mission to deliver a spy satellite to orbit, officials said.

The 20-story tall United Launch Alliance Delta 4-Medium rocket blasted off Tuesday afternoon, marking the first flight for the fifth configuration in the Delta 4 rocket family, the Santa Maria Times reported Wednesday.

The rocket's maiden voyage originally was planned last week, but crews needed time to review data about a possible problem with the upper-stage engine. Officials cleared the rocket for launch Monday.

Since it carried a payload for the National Reconnaissance Office, base representatives did not provide details about benchmarks of the flight, only that the rocket's nose cone separated. They also did not discuss the status of the satellite, its mission, cost or other details.

Because the Delta 4-Medium is the only Delta 4 configuration that hadn't flown, the flight represented "a significant milestone in Delta 4 operations for the nation," said Lt. Col. Brady Hauboldt, 4th Space Launch Squadron commander and Air Force launch director.

The blastoff was the 19th Delta 4 launch since the Air Force's Evolved Expendable Launch Vehicle program began in 2002, the Times said. Delta 4 rockets were developed under a program to simplify space boosters used to carry satellites into orbit for weather, navigation, imagery and other purposes.