International Space Station crew, left to right, Catherine Coleman, Alexander Kaleri, Dmitry Kondratyev (bottom), Scott Kelly (top), Oleg Skripochka and Paulo Nespoli. Photo Credit/NASA

Curious students took a break from the Christmas holidays Tuesday to gather at the Great Lakes Science Center in Cleveland, Ohio, for a question-and-answer session with U. S. and European astronauts aboard the International Space Station. The 20-minute session was part of Teaching From  Space, a NASA educational program established to encourage students to study math and science.

Station Commander Scott Kelly and Catherine Coleman, both of NASA, and Paulo Nespoli, of the European Space Agency, were quickly put to the test on a personal as well as a professional front.

Kelly, a twin, was asked what his mother would think if Scott and his brother, NASA astronaut Mark Kelly, were assigned to fly in space at the same time.

“My mother would be nervous and my father, too, and my grandfather,” responded Scott Kelly, who faced that very real prospect until just a few weeks ago.

NASA astronauts Scott Kelly, left, and Mark Kelly confer at Ellington Field in Houston. Photo Credit/NASA

Kelly’s near six month space station journey is scheduled to end in mid-March, when he and his colleagues descend to Earth aboard a Russian Soyuz spacecraft.

Mark Kelly will command the six-person crew of the shuttle Endeavour, which was to dock with the space station in early March. Endeavour’s 10-day mission is currently the final scheduled shuttle flight.  In early December, Endeavour’s 10-day voyage was postponed until April 1 because of  problems encountered with the shuttle Discovery.

Discovery’s mission has been postponed from Nov. 1 until Feb. 3 at the soonest, a bit of a disappointment to the Kelly twins, who would have been the first blood relatives to meet in space.

” If we were both in space at the same time, however,  they would understand it, and of course, they would have to live with it,” said Scott Kelly of the parental anxiety.  “Unfortunately, that is not going to happen now. So, that is something my parents will not have to worry about.”

Coleman was questioned about the kind of training the astronauts receive to prepare them for six months on the space station.

“There are people who have thought about everything that astronauts need to learn in order to live and work and do science experiments on the space station,” said Coleman. “Some of those things we learn in the United States, some of those things we learn in Russia. We also do training, which is very much like school. We go to class just like you do. We have tests. We do those things in Japan and Europe.”

Catherine Coleman Photo Credit/NASA

All of the station’s 15 partner nations have made contributions to the space station, and the astronauts are diligent in their preparations to make sure they know how each piece of equipment operates.

“I’ve spent the last two-and-a-half years learning those things,” said Coleman. “It’s pretty exciting to be up here putting all that knowledge to work.”

Nespoli was asked to compare living in the absence of gravity while aboard the space station with scuba diving?

European Space Agency astronaut Paulo Nespoli. Photo credit/NASA

“Yes, when I float around here, it reminds me a lot of scuba diving,” said Nespoli. “When I push off, it reminds me of when I was under water and pushed off. I was flying over coral reefs”

There are differences as well in how you control your body. The resistance to moving one’s body in water is not present in space.

“In the water, you can push off and steer to avoid another object or spin around,” Nespoli explained. “In space that  doesn’t work. If you are not careful, you will slam against the wall and do a lot of damage.”