Doug Wheelock, Shannon Walker, Scott Kelly, pictured left to right, discuss spaceflight with middle school students. Photo Credit/NASA TV

Three U. S. members of the International Space Station crew raved about the beauty of the Earth and discussed the risks associated with their work on Tuesday, as they fielded questions about life aboard the orbiting laboratory from students who attend two Washington D. C. area middle schools.

The 20-minute exchange with station commander Doug Wheelock, Scott Kelly and Shannon Walker was hosted by U. S. Secretary of Education Arne Duncan and Leland Melvin, an astronaut who serves as NASA’s Associate Administrator for Education. The encounter with students from the Hart and Deal Middle Schools was part of International Education Week.

U. S. Secretary of Education Arne Duncan, left, and Leland Melvin, NASA's Associate Administrator for Education, visit with Washington middle school students. Photo Credit/NASA TV

“Everyone would agree the most beautiful things we can see from the space station is our planet. There are so many beautiful things to see,” said Wheelock. “The Earth is like an explosion of color in this big sea of darkness.”

He recalled his favorite viewing experience.

“The Earth at night is just alive with life and motion. We can see lightning, aurora and city lights. It’s just absolutely beautiful,” Wheelock told the students. “Back in July and August we were able to see the Southern Lights, the aurora over the South Pole. We actually had a night where the moon was full and the sun was coming up. We had this beautiful aurora. The moon was shining off the aurora as was the rising sun. So, it was pretty dramatic. We were all glued to the window that night.”

The U. S. Gulf Coast at night from the space station. Mobile, Ala., is visible at the top left. To the southeast are New Orleans, La., and Houston, Tex. Inland, Shreveport, La., as well as Dallas and Fort Worth, Texas are also visible. Photo Credit/NASA

On Thursday, Wheelock, Walker and Russian cosmonaut Fyodor Yurchikhin will make a Thanksgiving return to Earth aboard a Russian Soyuz capsule, making a parachute descent into remote Kazakhstan at 11:46 p.m., EST.

When they leave, Kelly will take command of the station.

Tuesday, he discussed the risks faced by the astronauts as they spend six months at a time on the station conducting experiments in biology, physics, medicine as well as studying the Earth’s environment.

“Flying in space is somewhat dangerous,” explained Kelly.

“We do have things that go wrong,” he said, recalling the failure and recovery of an external cooling system pump in July and August. “We have ways to respond. So far, we have been pretty good at it.”

However, the greatest hazard is posed by the ride up to the station and the return to Earth.

“We are flying around the Earth at 17,500 miles per hour in a near vacuum. To get here requires an incredible amount of energy to accelerate to that velocity. To get home we have to remove that energy out of the vehicle, whether it’s a Soyuz or a space shuttle,” said Kelly. “Whether it’s NASA, or our international partners, they work really hard to make it as safe as we possible can. It has risk, but doing great things has always involved risk. I’m happy and proud to be a part of it.”

Another student wondered if the personalities of the astronauts change while they are in space, a question that caught Walker by surprise.

“I never really thought about it,” she said. “I don’t think my personality has changed, but I think my crewmates would be the final judge of that.”

Walker’s response was met with silence from her colleagues, then laughter.