By Bernie Woodall

DETROIT (Reuters) - A federal judge is set to decide on Thursday if the Nigerian man who pleaded guilty to trying to blow up a U.S. airliner bound for Detroit in 2009 will spend the rest of his life in prison.

A bomb hidden in the underwear of Umar Farouk Abdulmutallab, now 25, caused a fire but failed to explode on a Delta Airlines flight carrying 289 people on December 25, 2009.

U.S. District Judge Nancy Edmunds will decide whether Abdulmutallab should be sentenced to life in prison as called for under existing sentencing guidelines.

Abdulmutallab's lawyer, Anthony Chambers, earlier this week asked for a lighter sentence, saying the mandatory life sentence was too harsh for an attempted bombing that killed no one.

"Given the circumstances and what did NOT occur in the instant matter it is fair to say that the mandatory minimum sentence of life imprisonment is excessive and grossly disproportionate to the conduct," Chambers said in a court filing, emphasizing the word "not."

While not making a specific request, he asked on Abdulmutallab's behalf that the judge impose a sentence below the advisory guideline range because a life sentence would be a "misinterpretation of justice."

Prosecutors have urged the judge to give Abdulmutallab the maximum sentence - consecutive terms of life in prison.

In October, Abdulmutallab pleaded guilty days after his trial began, saying he had wanted to avenge the killing of innocent Muslims by the United States.

Court officials said that Abdulmutallab's parents and one of his sisters will be in the Detroit courtroom on Thursday. Six victims are scheduled to speak before Edmunds declares sentencing.

Abdulmutallab, who has been held at a federal prison in Milan, Michigan since 2009, will also be given a chance to address the court before sentencing.

Prosecutors also last week offered new details about how Abdulmutallab's plot was directed by U.S.-born Muslim cleric Anwar al-Awlaki, who had become an al Qaeda leader in Yemen.

Awlaki was killed in a drone attack in Yemen last September. In court papers, the FBI identified Awlaki as "chief of external operations" for al Qaeda's Yemen branch as well as an Internet-savvy propagandist and recruiter.

When the bomb caused a fire but failed to explode, Abdulmutallab was quickly subdued by passengers and crew. The incident led U.S. officials to bolster airport security, deploying full-body scanners to try to detect hidden explosives.

The judge is also due to rule on Thursday whether the prosecution can show a video that the FBI created to simulate the bomb Abdulmutallab tried to detonate.

(Editing by Will Dunham)