JUDY WOODRUFF: After traveling more than 300 million miles over six months, NASA's newest
Mars lander, the InSight, touched down on the Red Planet this afternoon.
It may be the eighth time NASA has landed a probe on Mars, but that didn't diminish
the celebration today.
WOMAN: Touchdown confirmed.
(CHEERING AND APPLAUSE)
JUDY WOODRUFF: Its descent from the Martian atmosphere has been described as seven minutes
of terror, as the spacecraft has to slow from 12,000-plus miles an hour to just five miles
an hour.
This probe is focused on learning more about the interior of Mars and the history of the
planet.
Our resident space observer, Miles O'Brien, has been preparing for this moment as well,
and he joins me now from Boston.
Miles, welcome back.
So, tell us.
Terror?
I mean, just how difficult was this?
MILES O'BRIEN: Well, Judy, imagine seven years of work all being distilled down to seven
minutes.
You know, the people who are in that room when they erupt with joy, they're kind of
like riverboat gamblers of science.
They put all their chips on the table, they invest a lot of time, and then they hope.
All these things have to go right.
The spacecraft has to separate, the back shell has to come off, the parachute has to deploy,
the landing gear has to go down, the radar has to work, the engines have to start, the
other -- the heat shield has to go away.
All these things have to happen in seven minutes.
There's really nothing they can do about it, because there's an eight-minute delay, just
things getting back to in from Mars.
And so they sit there and watch.
And when it works out, it is definitely a moment to savor.
JUDY WOODRUFF: So, I mean, 300 million miles, we can't even imagine how far that is, except
that we can see Mars sometimes.
But, technically, it's just as hard as it was the first time?
MILES O'BRIEN: Yes, there's nothing easy about this.
They kind of make it look easy.
They're kind of aw shucks about it.
They're calm in their transmissions.
But I think, when you see that eruption of joy, you realize what's going on inside.
There's a lot of nervousness, because, after all, they have worked so hard for this moment.
And now the science begins.
JUDY WOODRUFF: So, Miles, how can they tell that it worked?
I mean, what -- how do they observe it?
MILES O'BRIEN: Well, they have -- of course, the spacecraft itself has the ability to transmit
as it goes down, and it is able to relay information to orbiting NASA spacecraft already in orbit
around Mars.
And, this time around, there was something a little bit different.
It had two briefcase-sized spacecraft that were flying in formation with it.
It's the first time they have tried this.
And they served as a relay, sending information back to Earth.
That's an idea which was kind of an add-on to this particular mission.
It wasn't a metric for success or failure, but expect to see more of that in the future.
JUDY WOODRUFF: So literally the size of a briefcase?
MILES O'BRIEN: Yes, which is hard to imagine, 300 million miles, sending a briefcase out
there, and it ends up in the right place.
I mean, this -- it's kind of mind-boggling stuff.
JUDY WOODRUFF: So, as we said, they want to learn more about the interior of Mars.
What do they want to find out?
MILES O'BRIEN: Well, if you think, this is the eighth successful landing by NASA on Mars.
The seven previous ones have looked at the surface, they have looked at the atmosphere,
the ionosphere.
We know a lot of things about what we see on Mars and what's above Mars.
In this case, they're going beneath the surface.
Let's listen to the principal investigator.
He will give us the big picture, before I get into the details.
His name is Bruce Banerdt.
BRUCE BANERDT, InSight Principal Investigator: The basic idea of InSight is to map out the
deep structure of Mars.
We know a lot about the surface of Mars.
We know a lot about its atmosphere and even about its ionosphere, but we don't know very
much about what goes on a mile below the surface, much less 2,000 miles below the surface, down
to the center.
MILES O'BRIEN: So, 2,000 miles, that's a big distance.
They're not going that far.
However, they're going to be using a seismometer, which will measure Marsquakes.
And by doing so, you can actually tell a lot about the layers that lie beneath the surface.
They also have a probe that's going to go down about 15 feet, not quite 2,000 miles,
but in so doing, they will be able to tell how much the heat changes, the temperature
changes.
And they can actually interpolate that, they think, all the way down to the core of the
planet.
And speaking of the core, the big question among scientists, is it a solid core, a liquid
core?
They actually have a radio transmitter attached to this spacecraft that will be able to determine
how the planet wobbles.
And if it's got a liquid core, it'll actually slosh around a little bit and wobble a little
more.
So they will be able to determine that as well.
All of this comes out over the next year or so on Mars.
JUDY WOODRUFF: Fascinating stuff.
And, Miles, from this, you were telling us they can help -- it helps them decide what
they're going to do in the future as they study Mars.
MILES O'BRIEN: Yes.
I mean, ultimately the idea is to put human footprints on Mars.
The more you know about the place, the better you can think about where to go and what to
do and how to sustain life there.
And there's one other thing.
When you think about Mars now, it's really what Earth looked like four-and-a-half billion
years ago.
It's just that we have had a lot of things happening on our planet, plate tectonics,
et cetera, that have changed the surface and buried the evidence.
Well, the evidence is there on Mars.
And so it gives us some hints about our progression and how our planet has evolved.
JUDY WOODRUFF: Our Mars expert, Miles O'Brien, thank you.
MILES O'BRIEN: You're welcome, Judy.