SPOKESMAN: Three, two, one.
Emission and liftoff of NASA's "New Horizons" spacecraft.
JEFFREY BROWN: It's a mission to the edge of the solar system.
SPOKESMAN: To visit planet Pluto and then beyond.
JEFFREY BROWN: Today, NASA launched an unmanned spacecraft called "New Horizons" towards Pluto, the last unexplored planet. NASA officials said they were pleased with the launch.
ANDREW DANTZLER: It was a beautiful launch. And it's just hard to contain myself.
But I do want to point out that we talk about how fast this spacecraft is. But by the time you see this, if you watch on East Coast you see this news report at the 11:00 news, the spacecraft will already be past the orbit of the moon.
JEFFREY BROWN: The mission had been scrubbed two days running, but shortly after 2 p.m. this afternoon, the craft lifted off on an Atlas V rocket and sped away from Earth, the fastest spacecraft ever launched.
OMAR BAEZ: 36,256 miles an hour, that's how fast we're going, that's amazing.
You know, as Andy said, this is a team effort. And the team pulled it together.
JEFFREY BROWN: Pluto is the brightest body of the so-called Kuiper Belt Zone of the solar system. The "New Horizons" spacecraft will take nine years to reach Pluto, the final frontier of NASA's exploration of the planets which began in the early '60s with unmanned missions to observe Mars, Mercury and Venus.
JEFFREY BROWN: And one of the scientists on the project joins me now. Robert Gold is chief of technology at the space department of Johns Hopkins University applied physics lab, which partnered with NASA on this Pluto mission. He helped oversee the engineering and technology.
Welcome to you.
ROBERT GOLD: Thank you.
JEFFREY BROWN: Flying past the Moon by 11 tonight. You go that fast because it's so far?
ROBERT GOLD: And you want to get there in less than 30 years. And in this case, it will be about nine and a half years to actually get to Pluto and fly by.
And the way you do it is by having the very big rocket that we were on, that Atlas 5, and a very small spacecraft. The spacecraft weighs less than about a thousand pounds. And when you put that on top of the big rocket in upper stage, you end up going amazingly fast.
JEFFREY BROWN: You kindly brought a model of it. Show us what we want to know about this.
ROBERT GOLD: Well, when you look at the spacecraft, the most prominent thing is the big antenna. That has to point back to Earth to send some of the information back. And during most of the mission the spacecraft will be spinning. And it will spin around this axis of the antenna. So the antenna can continue to talk to Earth as the spacecraft spins.
JEFFREY BROWN: Let me stop you for a moment because one thing that I read that would seem kind of interesting is that the craft is almost like a bear in hibernation most of the time.
ROBERT GOLD: Yes.
JEFFREY BROWN: Is that correct and you guys sort of wake it up once a year?
ROBERT GOLD: Wake it up occasionally just to keep the cost of operating the spacecraft down. It's very expensive to use the deep space network and to have all the people operating the spacecraft.
One way to keep those costs down is to put it in hibernation during much of the cruise. And with that, you can then trim down the operations team to only a very few people and then build up the team and bring back the activity when you get to interesting times like when we fly by Jupiter and when we actually get to Pluto and Sharon.
JEFFREY BROWN: Now it's powered by plutonium.
ROBERT GOLD: Powered by a plutonium radioisotope power generator that is this black blob at the top end of the spacecraft.
What it really is, is a canister with radioactive material that is getting hot from the radioactive decay. And then it has a bunch of thermocouples. When you take dissimilar metals and touch them together, when one is -- one joint is hot and another joint is cold an electric current flows between them.
You put a bunch of those in here with some near the plutonium that is hot, some out near the fins that are cool, and you generate electricity. The whole thing generates only about 200 watts. A couple hundred watt light bulb has to operate the entire spacecraft for the full nine and a half plus years to get to Pluto and then beyond to the Kuiper Belt.
JEFFREY BROWN: So that was controversial, right, to use the plutonium? Some people were protesting.
ROBERT GOLD: Plutonium is a dangerous material - although this is not the plutonium used in nuclear weapons. This is plutonium isotope 238, which is not a nuclear weapon material. But it's still very dangerous.
JEFFREY BROWN: Now let me ask you what I'll call the $700 million question because I understand that is the cost of this. Why go to Pluto?
ROBERT GOLD: We live in a solar system that is about four and a half billion years old. And we want to understand what our neighborhood is like: Where did we come from? Where are we going? What do we live in?
We have flown by or orbited all of the other planets. And the biggest remaining question is what is Pluto like, and this is our chance. And for a nine and a half year cruise mission we can then finally see what this last member of the planetary system is all about.
JEFFREY BROWN: Well, tell us what we know now. It's a so-called ice dwarf, right?
ROBERT GOLD: Right.
JEFFREY BROWN: What does that mean?
ROBERT GOLD: Well, the inner planets -- Mercury, Venus, Earth and Mars -- are called the terrestrial planets. They're rocky. Then beyond them Jupiter, Saturn, Uranus, Neptune -- those are gas giant planets. They don't seem to have a definitive surface; they are covered in clouds made of condensed gases.
And then there are objects beyond -- of which Pluto is one -- that appear to be leftover pieces from the making of the solar system that have always been cold, composed probably of some combination of ice and rocks, and they're relatively small. But we believe there are quite a number of them.
JEFFREY BROWN: And you know, of course, that there has been the question of whether Pluto is, in fact, a planet.
ROBERT GOLD: Yes.
JEFFREY BROWN: There was -- I read an interesting thing today, Alan Stern the team leader of the mission, he was asked about this. And he dismissed the critics of Pluto as a planet and he said a quote I love. He said just as a Chihuahua is still a dog, these ice dwarfs are still planetary bodies.
Some people wonder about Chihuahuas, I guess. But tell us -- what is the issue here about being a planet or not?
ROBERT GOLD: Well, the issue is really that we've never had an official definition of what a planet is. So when we found Pluto roughly 60 years ago, we said, oh, there's the last planet.
Then we realized that there are other objects out there at the edge of the solar system in this region called the Kuiper Belt that are also planetary objects. So do we increase our number of planets as we find new ones?
But they are definitely planetary bodies. They are pieces from the creation of the solar system that are, many of them, relatively large. Pluto is about two-thirds the size of the United States across. What do we call them? They are planetary bodies. And we'll leave it to other people to argue: Is Pluto a planet?
JEFFREY BROWN: So the craft gets there in about nine years. And this is a fly-by, basically, right?
ROBERT GOLD: Yes.
JEFFREY BROWN: And what happens afterwards? Where does it continue on to and what does it look for?
ROBERT GOLD: Well, once we've flown by Pluto and seen what Pluto looks like, tried to understand some of what the composition of the surface is and the -- Pluto's atmosphere -- it has an atmosphere we know from Earth observations -- we then want to target one of these other Kuiper Belt objects, these other ice dwarf projects. We'll be mapping those as we go out, find the one that is easiest to get to and fly by it.
JEFFREY BROWN: All right. So we have to check back in 2015.
ROBERT GOLD: And then probably 2016 or 17 when we find one of these other objects as well.
JEFFREY BROWN: All right, Rob Gold, thank you very much.
ROBERT GOLD: Thank you.