American astronaut Scott Kelly completes first six months in space

HOUSTON -- Astronaut Scott Kelly spoke with the media Monday, summing up his six-month journey in space in just a few words: "I feel pretty good overall."

So, what do six mounts in space do to a person?

"As far as physically, I feel good. We have good exercise equipment up here," he said.

Kelly has been in space for 6 months. So far, so good. But he has 6 months to go and he's actually looking forward to it.

"I feel positive about it. If I manage my work and energy right, I will have enough in the tank to get to the end," he said.

The end for Kelly is not until March 2016. That's when all of Kelly's vitals will be measured against his identical twin brother, astronaut Mark Kelly. There is no doubt space has its damaging effects.

"There are effects of this environment, bone loss, vision, genetics, DNA, iron and proteins, things like that," says Kelly, as he floats in zero gravity in the International Space Station.

The real question at play here is the effects on the human body during long-term space journeys to Mars and beyond.

"Hopefully from these experiments we will find out if there are any cliffs out there and from that, figure out other areas we need to investigate so that we can eventually complete our journey to Mars and elsewhere," Kelly said.

It's all fascinating science and all so crucial for a trip to Mars, which would require one to spend nearly two years in space.

So, when will all of this happen? Well, the first trip for NASA is to land on an asteroid, in about 10 years. Then some five to 10 years after that, in the 2030's, it's to Mars and beyond. Maybe.