Iowan native astronaut Peggy Whitson, 57, made it pretty clear she would like to fly to Mars someday. 

But she dropped a fact I hadn’t considered. Whitson said she can’t fly again under current regulations because she is at her limit for radiation exposure. 
I can only imagine what happens when one spends 665 days 22 hours 22 minutes in space, more than any other U.S. astronaut. That has to be a lot of radiation.

But Whitson kind of smirks when she says she now has hit her limit, according to the current regulations. Does that mean she thinks the regulations should be relaxed? Are the regulations too tight? “Maybe. If we want to go to Mars, sure. We know what the risk is. We need to work on minimizing the risk. 

What is her percentage chance of going on a Mars expedition? “I have no idea. It’s pretty minuscule at this point, in the sense that we aren’t ready to go to Mars yet. That’s a few years down the road. 

“Right now, the regulations are such that I have reached my radiation life limit. However, if there was a commercial flight or something, I could potentially fly independently of NASA.” 

John Glenn was 77 when he went on his last mission. So there is data about bone density and other effects of spaceflight on an older man. Would Whitson consider adding some data on a female 70-something later? “If I got asked to go, that would be great. I love being up there. It’s very satisfying and gratifying to work on something that is bigger than yourself. It’s about the space program, and exploration.” 

Book? Maybe. 

Part of NASA’s job is to encourage young people and to inspire them to become scientists and engineers. “When you hear the fourth-graders’ questions, how can you not like that? They are so excited.

“We do need to encourage our young ladies to realize that it is not uncool to be a scientist.”

What is cool? 

“Discovery. I just enjoy answering questions. 

“It was a dream. When they selected the first female astronauts, I think it changed from being a dream into a goal. After that it was just persistence. Dedication. 

“I wanted to be an astronaut. I was 9 years old when I saw Neil Armstrong and Buzz Aldrin walk on the moon.”