The hearing was supposed to be pro forma — there was no question that a Maryland man would be sentenced to 13 years in prison for selling U.S. secrets to an undercover FBI agent posing as an Israeli spy.

Instead, the proceeding Wednesday in the District’s federal court became a final public platform for prosecutors and defense lawyers to paint divergent portraits of Stewart Nozette, a brilliant space scientist whose fall from grace was either triggered by greed and hubris or overzealous federal agents targeting a troubled man.

Wearing an orange jumpsuit, Nozette spoke publicly for the first time since his October 2009 arrest, saying he accepted “full responsibility” for his actions and wished to apologize to friends and family members for any pain he had caused them. The Chevy Chase resident added that he regretted not informing authorities when he was first approached by a man he thought was working for the Mossad, Israel’s storied intelligence service.

As expected, U.S. District Judge Paul L. Friedman sentenced Nozette, 54, to 13 years in prison — as specified in the deal the scientist had reached with prosecutors in September — and a little more than three years for unrelated fraud and tax evasion convictions. The sentences, which included $217,795 in restitution payments, will run concurrently.

The hearing concluded the sad legal saga of an accomplished space scientist who held a number of sensitive government jobs and sketched out a successful lunar mission on a napkin. He is credited with helping discover water on the moon, and a prototype of a satellite he helped design hangs in the Smithsonian National Air and Space Museum.

While pushing the frontiers of space, Nozette was lining his pocket, according to prosecutors who allege he inflated in-voices and travel vouchers over at least two decades. In 2005, authorities launched an investigation that later determined Nozette — then a contractor — submitted inflated bills to several federal agencies, using the proceeds to pay personal expenses that included a car loan, a mortgage and even swimming pool cleaning.

The downfall

In January 2009, Nozette pleaded guilty to conspiring to defraud the government of $265,205.57 and to evade more than than $200,000 in taxes.

“He really does have a brilliant scientific mind,” said federal prosecutor Michael Atkinson of the District’s U.S. attorney’s office. “But there is no doubt he also had a criminal mind, and he used that criminal mind to advance the interests of Stewart Nozette.”

The fraud investigation eventually led to his downfall on espionage charges. While searching Nozette’s home in 2007 in connection with the fraud case, federal agents found classified information on computers and grew concerned about a contract he had with an Israeli aerospace company. They also discovered a 2002 e-mail that said Nozette was willing to provide classified information to Israel or another undisclosed country.

By September 2009, an FBI agent posing as a member of the “Mossad” approached Nozette and, in recorded meetings, asked the scientist whether he would spy for Israel. They agreed to exchange information through a post office box in the District, and Nozette collected more than $20,000 in cash for providing classified information about such defense programs as satellites and early-warning systems, according to court papers that accompanied Nozette’s September guilty plea to one count of attempted espionage.

Federal prosecutors said Nozette’s motive was simple: greed. In court Wednesday, prosecutors played a video clip of the last meeting between Nozette and the undercover FBI agent in a Mayflower Hotel suite that they said demonstrated his determination to exchange secrets for cash.

In the video, Nozette is wearing a dark blazer over a button-down shirt. Reclining on a couch, he tells the agent, “I gave you, in this first run, some of the most classified information that there is.”

“I’ve crossed the Rubicon,” the scientist later says after accepting an envelope stuffed with $10,000 in cash. “I’ve made a career choice.”

After playing the clip, Assitant U.S. Attorney Anthony Asuncion said Nozette “agreed to be a traitor to the United States with a smile on his face.”

Frustrated

Conceding that Nozette had made mistakes, his attorneys countered that their client was unfairly targeted by FBI agents who “manipulated and exploited” a vulnerable man under enormous strain. They noted that Nozette was deeply frustrated by the government’s fraud prosecution, which resulted in NASA denying him entry to Goddard Space Flight Center during an important lunar mission.

Meanwhile, as part of his plea deal, Nozette was working covertly for federal agents, wearing a wire and making recorded phone calls with others he suspected of committing fraud. The undercover assignment was stressful, and Nozette worried that he might be in danger — at least two targets had guns and one belonged to a “violent hate group,” defense attorneys said in court papers.

As the months wore on in 2009, the lawyers said, the scientist contemplated suicide and became increasingly despondent about facing prison time.

“They knew they were dealing with an emotionally and mentally damaged subject who was facing the loss of his life’s work and prison,” defense attorneys Robert Tucker and John C. Kiyonaga wrote in court papers.

Bradford Berenson, another of Nozette’s attorneys, added that agents trailed Nozette for a year without uncovering evidence that he passed secrets to a foreign power. Instead of asking him questions, agents crafted an elaborate sting that also took advantage of Nozette’s sympathy for Israel. Nozette is Jewish and his father “fervently supported” the Jewish state, according to defense lawyers.

Even then, his attorneys said, Nozette initially refused to divulge classified information before “his ultimate surrender.”