Senators briefed on the latest from the International Space Station

WASHINGTON -- Sens. Bill Nelson (D-Fla.) and Ted Cruz (R-Texas) took a break from earthly political matters Tuesday to talk to NASA astronaut Tom Marshburn, one of two Americans aboard the International Space Station.

Marshburn, who has been at the space station since December 2012, said that his experience has given him a newfound appreciation for his home planet.

“I wish every head of state could see the Earth from the cupola,” he said, praising the planet’s beauty, nuance and lack of borders from his exceptionally high vantage point.

But not everything about the Earth seems perfect from space.

“Our existence on there appears very fragile, the atmosphere is very thin,” Marshburn added.

Nelson, who flew on the space shuttle Columbia in 1986, and Cruz, a “co-leader” of the science and space subcommittee, quizzed Marshburn on his adjustment to life in zero gravity and his current scientific research.

“I’m feeling adapted, feeling great,” said Marshburn, whose background is in medical science. “It’s been wonderful to be efficient and get a lot done up here.”

Ticking off a number of projects that included a comparison of spinal ultrasound studies with MRIs, protein crystal growth and vaccination experimentation, Marshburn acknowledged the difficulty of summarizing the numerous ongoing projects in just a few minutes.

As for getting those projects back to the ground, Marshburn was upbeat about the possibility of private space companies providing the vital link between the space sation and Earth.

“Going into space is not easy, we can still barely do it,” he said, but private firms will eventually be able to get to the space station “cheaper, better, faster” than current expeditions.

He also provided some perspective on the day-to-day life of an astronaut on the space station. They wake up, are given their orders from ground control and except for food and exercise breaks, spend most of their time working on experiments. Nights are free for recreation or for calling home, but Marshburn acknowledged that “I’m partial to do a little bit of homework at night.”

Nelson and Marshburn both expressed hope that the space station, nearing its 13th year of occupation, will serve as a model for an eventual mission to Mars.

“I believe I’m living and breathing in the first Mars vehicle,” Marshburn said, certain that lessons in water retention, on-board power and life in zero gravity will prove vital to manned missions to the Red Planet.

Of course, politics weren’t entirely removed from the event. After the conversation was through, Cruz jokingly asked who would get the long-distance bill for the call.

“Not the U.S. taxpayer,” Nelson replied.

Follow Politics Now on Twitter and Facebook