AMNA NAWAZ: For the first time in more than 50 years, the U.S.

is sending astronauts back toward the moon.

MAN: GLS is go for core stage engine start.

Integrity, good roll pitch.

MAN: Roger, roll pitch.

AMNA NAWAZ: Incredible stuff.

Just moments ago, NASA launched Artemis II from the Kennedy Space Center in Florida, sending a crew of four astronauts on a 10-day voyage around the moon and back to Earth.

If all goes as planned, they will travel farther into deep space than any humans before them.

The flight marks a key step in the broader Artemis program, which aims to put humans back on our moon's surface by 2028.

And joining me now from the Space Center in Florida is our science correspondent, Miles O'Brien.

So, Miles, take us into that moment.

What was it like to see liftoff there?

Just tell us what you saw and heard around you.

MILES O'BRIEN: Well, I have covered probably 40 shuttle launches in my career, and nothing was like this.

This was a much more powerful rocket, a rocket that is on its way to another celestial body, four people on board, lifted off the planet by an orchestra, a symphony of work on the part of a team here that put it all together.

There were some glitches in the countdown, which caused some concern, but, in the end, they worked them all out and they had a very clean ride to space.

They're now in space and beginning the process of checking out this vehicle on a test flight that will last nine days and take them around the moon.

AMNA NAWAZ: So, Miles, you mentioned a couple of glitches there.

I know folks who are watching may have seen some delays.

What was going on there?

What should we know?

MILES O'BRIEN: You know, in the end, it's minor stuff.

There was problems with some batteries and battery indications.

There was a loss of telemetry.

Briefly, there was concern about the launch termination system.

All of it got worked out.

I will say this.

There's been a lot of concern that this team here doesn't have enough practice, because Artemis has flown so infrequently.

But, clearly, they have done a good job practicing.

They worked these problems efficiently and they got this rocket into space safely, and so far, so good.

AMNA NAWAZ: So, Miles, stay with us.

I think we're having a few connection issues.

We will see if we can push through them here, because I'd love to hear more about what exactly this mission entails.

What are they hoping to do over the next nine or 10 days?

MILES O'BRIEN: They're going to take a long pass around the moon, and it's the first mission like in 53 years, since Apollo 17.

It begins a campaign which NASA hopes will lead to a permanent encampment on the moon and understanding how to live on a celestial body and do science there.

AMNA NAWAZ: And we want to reiterate here, of course, these astronauts are not going to land on the moon.

That's the work of Artemis IV down the line.

So what do they hope to pull from this that will help lead and help inform future missions?

MILES O'BRIEN: This is about wringing out the potential bugs in the space capsule, learning how to live in it, how to eat in it, how to cook food, how to go to the bathroom, make sure everything works well.

And then, ultimately, the most important thing is, will that heat shield do its job when they return?

It has to endure 5,000 degrees Fahrenheit heat as it comes in.

And, on Artemis I, they had some problems with it.

They made some redesigns and changed the flight plan.

Hopefully, that won't be an issue.

AMNA NAWAZ: So, there's a lot at stake for these four astronauts.

There's some firsts aboard that craft as well.

Tell us a little bit about the four astronauts on board this mission.

MILES O'BRIEN: It's one of the tightest crews I've ever seen.

Reid Wiseman, Navy test pilot.

Glover, who is his pilot and who is a Navy test pilot as well, he is the first African American to go to the moon, Christina Koch, who is the first woman to go to the moon.

And we have a Canadian astronaut, who is the first Canadian to go to the moon.

So it is a diverse crew, a crew that has been planning for quite some time for this moment, and we'll see how they do in space.

AMNA NAWAZ: So tell us about the journey that they're going on now.

I know they're traveling in NASA's newest spacecraft.

That's the Orion craft.

What should we know about what led to this craft taking off now?

What's it going to be like for them on board?

MILES O'BRIEN: Well, the Orion spacecraft is about the only thing that survives from the original George W. Bush Constellation plan to send astronauts to the moon, which was announced back in 2004.

The Obama administration canceled it, and what survived was Orion and a rocket called Space Launch System, which is derived from shuttle parts, shuttle solid rocket boosters, shuttle engines.

As a matter of fact, some of the engines we saw work today actually flew on the space shuttle, had been used on the shuttle.

And so that idea was to make it go faster.

But, in the end, it turned out using all those old parts, integrating them into the new system was -- actually slowed the process down.

AMNA NAWAZ: That is Miles O'Brien witnessing history there for us down at the Florida Space Center.

Miles, thank you so much.

MILES O'BRIEN: You're welcome.