As Paul Root Wolpe points out the toy space shuttles and bug-eyed Martians in his office, his face lights up, his hands become animated, and he's clearly excited by his position as NASA's first chief bioethicist.

He makes sure that America's space agency takes good care of its human research subjects on Earth and beyond. Surprisingly, he works regularly from his Cheltenham home, not Cape Canaveral.

Five years ago, NASA decided it needed someone who could advise it on ethical guidelines in its cutting-edge scientific and medical research.

"Space flight is true exploration. There are health decisions and risks that you need to mitigate. All have ethical overtones," said Richard Williams, NASA's chief health and medical officer. Wolpe came highly recommended as an "intellectually powerful guy," Williams said.

"It's such a wonderful opportunity," Wolpe said. "I couldn't say no. I had no idea what it was going to be like, what I was going to do. "

Two or three times a month, Wolpe travels to NASA's headquarters in Washington. He has visited almost all the U.S. space centers. He also attends international conferences, writes papers, and sets guidelines for future space endeavors.

His latest NASA project, he said, is "developing new policies for long-duration flights" to Mars and the moon, which could start as early as 2020.

 Wolpe works out ethical solutions that range from deciding what should be done with an astronaut who "becomes psychotic and attacks" the other crew members to working with Williams in determining the level of radiation to which an astronaut can be safely exposed, he said.

 Wolpe 's NASA work is "frontier," said Art Caplan, director of the University of Pennsylvania 's Center for Bioethics. "It opens doors merging engineering, ethics and medicine that you don't see anymore. "

When Wolpe isn't working for NASA, which takes up almost a third of his time, he teaches Penn students, from undergraduates to medical residents.

He is a senior fellow at the Center for Bioethics and heads a program in psychiatry and ethics in the psychiatry department.

"No specialty of medicine has more ethical issues than psychiatry," Wolpe said. "Psychiatry is the designated agent of social control. Psychiatrists can incarcerate you against your will. "

One of his specialties is neuroethics, a burgeoning field that explores the ethical issues of the brain as a private domain.

"I look at ethical questions that arise because of neuroscientific advances, such as the use of mood-altering drugs and drugs that increase cognition - attention, memory, calmness; brain implants, such as fetal cells or deep brain stimulators - or any technology that diagnoses or changes brain function," he said.

Look for Wolpe on a forthcoming National Geographic special about using brain-imaging technologies, such as MRI, to detect lies. In fact, Wolpe founded the Neuroethics Society in May.

"At NASA, he looks at pioneers. In neuroethics, he is a pioneer," Caplan said.

 Wolpe 's office is full of toy space shuttles, Martian key rings, and brain models. A newspaper political cartoon hangs on his wall, parodying the "NASA Ethicist" as a space shuttle crewmember with the phrase "Sure it's Worth the Risk" looming above his head.

 Wolpe remembers exactly where he was when he saw Neil Armstrong take the first steps on the moon in 1969. He was 12 years old, watching the monumental event with his family at a Long Beach Island vacation house. Never did he dream he would grow up to become NASA's first chief bioethicist.

Becoming a bioethicist wasn't the career Wolpe had embarked upon. He studied sociology but was interested in medicine and biology.

In those days, you couldn't get a degree or certificate in bioethics. Wolpe said he "started thinking and writing" about bioethics before he realized he was becoming a bioethicist.

After earning a doctorate in medical sociology from Yale, he returned to the Philadelphia area to help take care of his mother, who had suffered a stroke. Thinking he would be here for only a year, he ended up staying for good.

In love with Montgomery County's stone houses in charming old neighborhoods, Wolpe calls the area "beautiful. " His two daughters attend Cheltenham High School.

He met his future wife, Valerie, when they were studying at Penn. Root is his wife's maiden name, and they took on the last name Root Wolpe when they married.

 Wolpe credits his father - Rabbi Gerald Wolpe , who once led the Har Zion Temple in Penn Valley - as an influence on his career choice.

As a son of a clergyman, he watched his father grapple with ethical issues all the time.

"My parents always had a suspicion that I might become" a rabbi, Wolpe said. Instead, two of his brothers became rabbis and he became a bioethicist.