The shuttle Discovery brought Lisa Nowak back to Earth, but you couldn't tell by looking at her. In the heady days after her journey into space ended last July 17, a beaming Nowak basked in her moment, particularly at a welcome-home bash for her and her fellow shuttle astronauts in Houston. At the party "Lisa seemed great," says Evelyn Husband, 48, the widow of Rick Husband, who died in the 2003 Columbia explosion. "She was happy about the flight; it had gone really well. She was in great spirits. I had no idea there were any problems in her marriage."

Nowak's time on top of the world was, it turns out, brief. Months after the party, she separated from her husband of 19 years; just weeks after that came the love-triangle showdown that has made her, for all the wrong reasons, the world's most well-known astronaut. Free on bail after allegedly attacking Colleen Shipman with pepper spray in Orlando Feb. 5 (the most serious initial charges against her were attempted kidnapping and murder), Nowak–back in Houston and outfitted with an ankle monitor–is waiting for prosecutors to hand down formal charges. In the meantime members of her extended family at NASA, several of whom spoke with PEOPLE, try to understand what led Nowak, 43, down a desperate path. "She was always very kind and wonderful, very leveled-headed," says Evelyn Husband. "There has got to be more to this story than anyone knows."

This much seems clear: Nowak's romantic interest in astronaut Bill Oefelein, 41, set the stage for her downfall. Part of the same training class at Houston's Johnson Space Center, Nowak and Oefelein "were always together, whenever they had a chance," says a contractor who works with NASA and knows them both. Still, the easy-going Oefelein, divorced in 2005, "was not known as a womanizer or someone who was involved in flirting," says Susan Kilrain, 45, a former astronaut who piloted two 1997 shuttle flights and worked with Nowak and Oefelein. So–were the two having an affair? "As far as I knew she was infatuated with him," says Kilrain, "but we don't know if there was really a relationship."

As for Oefelein, sources tell PEOPLE he had been seeing Colleen Shipman, 30, an Air Force engineer, since they met at a NASA party last December. "They were dating," says Missy Ballentine, 39, a paramedic who lives near Shipman in Cape Canaveral, Fla. Another neighbor, who often saw them together, says, "It was, 'sweetie, honey,' hugging, kissing, loving on each other. They were just so happy."

In early February Shipman flew from Orlando to Houston to spend the weekend with Oefelein, says Ballentine. According to police, when Nowak learned about the trip she followed Shipman back to Orlando, packing a knife and BB gun and driving more than 900 miles (Nowak's children were with her husband, Rich, says Kilrain) to confront Shipman at the airport. This kind of behavior "is completely off the radar for anyone," says Kilrain, but especially "for someone like Lisa, who was so nice and normal."

Something apparently caused Nowak to snap–but what? The stress of being both an astronaut and the mother of three children, including 5-year-old twins, is not explanation enough, says Susan Kilrain. "Most married women with children who have flown in space have no issue with it," she says. Yet Nowak may have been vulnerable to a unique set of pressures. She was part of only the second NASA launch after the harrowing 2003 Columbia shuttle explosion, an event that had a profound effect on her. Four of her former classmates, including one of her best friends, Laurel Clark, were among the seven astronauts who died in the tragedy. After the explosion "Lisa was there for my son Ian when I was in really bad shape," says Laurel Clark's husband, Jonathan, a former NASA flight surgeon. "She would take him and do stuff and really be there for him. That demonstrates her level of commitment to others." Says Evelyn Husband: "Her outpouring of love and support was monumental."

But Nowak's deep concern for members of her NASA family, says Clark, meant that she had less time for her own husband and children. "Instead of being there with her kids, who were also upset about the accident, she was gone a lot," says Clark. "She made this huge sacrifice to help support our needs, even at the expense of her own family."

Nowak may also have felt the inevitable letdown that comes after astronauts return from space. "They have this tremendous high, and then when all the hoopla is over, boom–there's this emptiness, this vacuum," says Clark. "Sometimes when you're in that situation you do things to fill that void, to keep the rush going." Whatever strain Nowak may have felt in the months after returning to Earth, seeking help inside NASA was not a likely option. "You just don't say, 'Hey, I need to go to a psychiatrist,'" says Kilrain. "If you do, you're shooting your career."

While NASA officials sort out the relationships between Oefelein, Nowak and Shipman, all three are staying out of the public eye. (Nowak was put on leave, while Oefelein took a leave to be with Shipman in Florida.) "Colleen is holding up well, considering the circumstances," says her neighbor Missy Ballentine. "She got the bad end of this whole thing."

Nowak's situation, though, is the most serious: If convicted of attempted murder, she could face life in prison. "Lisa is doing okay," says Father Dominic Pistone Jr. of Houston's St. Clare of Assisi Catholic Church, who met with Nowak after mass Feb. 11. "We prayed together. A lot of people are lifting her with prayer." Nowak's sudden fall from grace, on the heels of her greatest triumph, has left her friends and colleagues heartbroken. "She's a good person who has taken a huge stumble, and we have to try to help her get her life back together," says Jonathan Clark. "Nobody else has been through this; she's breaking new ground. I just wish I could tell her, 'Hey, it's going to be okay.'"

  • Contributors:
  • Alicia Dennis/Austin,
  • Wendy Grossman/Houston,
  • Amy Green/Cape Canaveral,
  • Jeff Truesdell/Orlando.
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