On July 20, 1969, Neil Armstrong became the first person to walk on the moon. For almost 20 years, New Yorker Mike Massimino realized his dream, working for NASA. Then, it was time to come back home, to talk about and teach the lessons he learned in space. NY1's Budd Mishkin filed the following report in May of 2015.

How do you explain your work when most of us don't understand it?

"It was easily explainable," Mike Massimino says, laughing. "I mean, it's not rocket science. [laughs]"

Actually, it is. But not to Mike Massimino, the down-to-earth astronaut.

Massimino flew two space shuttle missions to repair the Hubble Telescope while working for NASA. He has returned to New York to teach at his alma mater, Columbia University, and serve as the Intrepid Museum's senior adviser on space programs like the Hubble at 25 exhibition.

"Coming inside of here underneath the space shuttle and seeing my tools that we used in space, yeah, no, it never ceases to be cool, to be exciting, the sense of wonder," he says.

Massimino felt a sense of wonder on his missions into space in 2002 and 2009, and a sense of purpose.

The Hubble telescope was designed to gather information about our universe from beyond the earth's atmosphere. Massimino put in thousands of hours of preparation but still worried what the history books would say if something went wrong.

"The age of the universe is this, you know, and they can tell that to the kids, you know, years from now," he says. "But what it would say is, we would know the age of the universe, but Mike broke the hubble space telescope. We would know this answer, but Mike did this. So I didn't want that to be the legacy."

One part of his legacy is that Massimino was the first astronaut to tweet from space, drawing attention from Saturday Night Live.

"Saturday Night Live—Mike Massimino tweeted 'Launch was awesome,' and in 40 years, we've gone from 'One small step for man, one giant leap for mankind' to 'Launch was awesome.' If this guy ever meets life on other planets it'll be, you know, they showed me tweeting, 'Geez, dudes, look, aliens!'" he says. "So they gave me a pretty good shot, but what it did is, it got my kids interested in my space travel, so they were very excited that they mentioned us on Saturday Night Live."

Massimino says Earth looks like a "beautiful oasis" from 350 miles above the planet's surface.

Mishkin: At the risk of asking an incredibly stupid question, are there astronauts who have a fear of heights?
I don't like heights.

"You realize if you let go, you're just going to float. That's hard. That was kind of hard to get used to, that, 'Yeah, alright, I'm going to let go. I'm not going to fall. I'm going to be OK,'" Massimino adds. "But I don't like going along the side of a building and looking over. I don't like that."

Massimino wore an FDNY hat in space to honor his father, a one-time New York City Fire Department inspector, and the firefighters killed in the September 11th attacks. He took home plate from Shea Stadium for his beloved Mets. And he took a lesson he learned years ago from his Uncle Frank, fixing the oil filter in his car with a huge screwdriver when Mike was still a kid.

"I swear to you, Budd, I was up there in space, I was pulling this handrail off that was stuck. We had a problem with some bolts, and they told me to try to yank it off, and I was like, 'This one's for you, Uncle Frank,' and I used the exact technique that Uncle Frank used to break it," Massimino says. "So you never know what you're going to learn when you're nine years old in your neighborhood that can help you later on in life."

There were plenty of lessons learned from his two missions. Massimino thought his time in space would mean that he wouldn't sweat the small stuff back on Earth.

"'Going back to life now is going to be easy.' Nothing could be further from the truth," he says. "I'm telling you, it's a lot easier out there than it is down here."

"When I got back, the first thing I noticed on my second flight was shingles missing from the roof of the garage."

As a guy who grew up on Long Island, Massimino knew a little something about commuting. But nothing like this.

"I'm in my front yard, and a few hours earlier, I was up there," he says. "So it's the same day. I started the day up there, and I'm finishing the day down here in my yard."

His two flights into space confirmed what Massimino already knew about life back here.

"It's such an intense experience, and then you come back and it's like, 'Man, I really just want to go to a baseball game again, you know, watch my kids do something or, you know, mow the lawn,'" he says.

"As cool as space is, I think it also gives you an appreciation for how nice we have it."

Mike Massimino was seven years old in 1969 when man first walked on the moon.

"That really got my attention as a little boy," he says. "And it wasn't just a passing fantasy like, 'Oh, this is cool, and what's next?' It really struck me as a little guy that this was the most important thing happening."

Years later, he left Franklin Square, Long Island to go to Columbia.

"Coming from Long Island, where I grew up, to the Columbia campus, it was kind of like going to Mars," Massimino says.

"My visit when I was a senior, and first time I'd been on campus and I looked around, saw the libraries on either end of college walk, and I said, 'Wow, people must learn here.'"

Massimino excelled at Columbia and at graduate school at MIT.

The movie "The Right Stuff" rekindled his love of the space program.

He got married, raised two kids, worked at McDonnell Douglas, then taught at Georgia Tech.

He also started applying to NASA to become an astronaut. Three times, he was rejected. The fourth time, he got in.

"It really is not that uncommon, and a lot of astronauts have applied more than I did," Massimino says.

"People who have been successful and achieved a dream, whatever their job might be, very rarely are they the people that have been successful on the first try."

"Hey, I'm trying to do something that is not that easy to get a chance to do, you know. The odds of it are next to zero. They only pick a handful, and they have thousands of very well-qualified people, very impressive people applying to do this job. They're only going to pick a few, you know. What's the chances of me getting picked? Well, pretty close to zero. But it wasn't exactly zero."

Massimino was able to realize his dream, and is now reminded of it all over again at the Intrepid's Hubble at 25 exhibition.

One special memory? As part of his training, Massimino spent hundreds of hours in a pool designed not for swimming, but training spacewalkers.

"The body position, the choreography, the hands, handoffs of tools, and working together with your team is very important," Massimino says. "And we can't just float around here. There's no anti-gravity room. So what the pool does is, it gives us as close as we can get to that."

Massimino retired from NASA in 2014. Whereas NASA was the only choice for space travel when Massimino attended Columbia, now his students there can pursue the possibility of working for commercial space travel companies.

Massimino: It's open, it's wide open, and it is, so it's different. It's not just the government now that's looking at possibilities. It's these commercial entrepreneurial companies that I think make it very exciting for these students
Mishkin: And as a NASA guy, is that a good thing?
Massimino: Yeah, absolutely.

Massimino is busy, at the Intrepid, at Columbia, with media and public appearances because of his engaging personality and ability to translate the world of space, even if he says it's not rocket science.

He's not a man to live in the past, but a rich past it is.

"The memories are so rich and thick, and it's almost like it was a dream. Did it really happen?" Massimino says. "And then I come here and I'm like, 'Yeah, it did.'"