Detailed analysis of the redesigned space shuttle booster fired last week shows the deliberately flawed rocket's safety features did their job, Morton Thiokol Inc. officials said Monday.

Company and NASA engineers have torn down the aft skirting and nozzle section of the 126-foot-long rocket, which was fired last Thursday at Morton Thiokol's plant 25 miles west of Brigham City. The test was the fifth and final firing needed to qualify the booster for flight."Everything continues to look very, very good," Morton Thiokol spokesman Rocky Raab said of the weekend examinations. "No problems whatever were uncovered . . . . From what they've seen so far, it looks like the best nozzle yet."

Engineers also peered inside the nozzle section, looking for any indications of unexpected failure in the rocket's features designed to contain super-hot gases, Raab said.

NASA grounded the shuttle program following the Jan. 28, 1986, explosion of the Challenger shortly after blastoff. Seven astronauts died. A presidential commission blamed the disaster on a faulty booster rocket seal that allowed gas to escape and ignite the spacecraft's external fuel tank.

"The internal inspection also is very good. The outer boot ring looks great, and everything else shows no anomalies that they can detect," Raab said.

He said detailed rocket inspection and analysis will continue through the rest of the month.