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Today, I am going to talk to you about 
limits with a question mark.

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Are there limits?

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I am going to use two examples.

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One is the orbiting and landing 
of an asteroid with NEAR spacecraft.

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NEAR stands for 
Near-Earth-Asteroid-Rendezvous.

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And the other is exiting 
the solar system with Voyager.

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This is the kind of thing

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that is very much in line with 
the theme of Uncharted Waters,

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which, of course, is the theme 
of this conference.

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You know that we don't know 
a lot about asteroids,

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and we certainly did not 
fifteen years ago.

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We didn't know 
if they were a solid body

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or a rubble pile, a bunch of rocks.

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Are they moving together in space?

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So the idea is to leave Earth
and go and orbit an asteroid

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which is typically not spherical, by the way.

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And nobody had orbited 
a non-spherical body.

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So, asteroids, there are lot of them

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that go orbiting in the vicinity of Earth.

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As you can see here is the orbit of Mars

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and here is the orbit of Earth,

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and these are a few of the asteroids

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that cross the path of Earth.

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And, of course, we have been lucky

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that we haven't had too many collisions.

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There have been collisions
as I am sure you have heard.

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So the idea is to go to one of these,

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orbit it and study it 
for a long period of time.

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To do that you need the spacecraft.

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We started the work two months 
before this picture was taken.

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You see the spacecraft on top
of what we called a shake-table.

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Which means that we take 
the spacecraft, once it is finished,

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and then we vibrate it to a level

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which it is going to experience

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as it goes up on top of the rocket,

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through the atmosphere 
and then into space.

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And it better survive that, 
otherwise it will not work.

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So, that's what we did.

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The spacecraft and we moved 
on to Cape Canaveral.

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We put it on top of the rocket, 
as you can see here,

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and you can also see 
there is a protective shell

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which is called the heat-seal

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simply because it protects 
the spacecraft

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as the rocket moves through 
the atmosphere at a very high rate.

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(Buzzing sound)

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This is sort of my last walk

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through the tower 
that surrounds the rocket.

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By the way, the young lady that you see
is the first program manager

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that I appointed 
to a NASA planetary mission.

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And I am very proud 
of having worked with ladies

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who really know how to do it.

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(Applause)

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So this is the rocket and 
you can see the exhaust,

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it's a little bigger 
than your car exhaust.

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These are just the solid rockets

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that surround 
the main body of the rocket.

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And then, of course, when 
the fuel is exhausted from these,

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they fall off and then we go on
to the next main tank of the rocket

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and it goes up.

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This lasted a long time

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so I am not going to tell you a lot more
and spend time on it.

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Finally we launched on February of 1996.

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What you see in this ...

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This is Eros, this is the asteroid.

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We put the spacecraft around it into orbit,

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and it rotated every 
about 6 1/2 hours, or so.

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So the spacecraft is rotating

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and watches the asteroid 
as it rotates around.

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Getting there, of course, 
wasn't simple.

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So we launched and then we went

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by the asteroid Mathilde in 1997.

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We came back to Earth 
to change the plane of the orbit

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so that we could match 
the trajectory of the asteroid.

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And then, something happened

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just before we were 
ready to get into orbit.

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That is, we fired the onboard rocket

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and we lost the spacecraft.

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No communication
for almost 24 hours.

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It's the worst thing.

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It can ruin your whole day
when you are in this business.

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(Laughter)

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But fortunately we had built 
enough redundancy into the system

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that 24 hours later 
we got a weak signal

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and we got the control 
of the spacecraft again.

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We found out what happened,

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and it turned out that the two computers 
on board had a disagreement.

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The spacecraft computers couldn't 
agree with propulsion in engine computer

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and we got in trouble.

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We lost some fuel.

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We went around the Sun once more 
and finally we got into orbit.

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As we were approaching Eros, the asteroid,

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on February 12, two days 
before Valentine's day, mind you.

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Here was the picture,

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it looked like a heart.

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Of course we knew 
it was an optical illusion

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and, of course, 
we never published the picture

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because we would get 
into all kind of trouble.

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And when we got close, 
as you will see,

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what happened is that 
you had these three craters

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that were arranged in a triangle,

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and they looked with 
a kind of Sun angle and the shade,

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it looked like a heart from a distance.

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So, that is the kind of stuff 
that you see in the tabloids

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that in the United States 
we pick out in supermarkets.

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Supermarket counters.

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You know ... "Heart on Eros" ...

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So much for that.

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It was big news that a NASA spacecraft 
orbited an asteroid on February 12.

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CNN is very loud everywhere it goes,

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including the United States.

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(CNN Speaker): A close encounter

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between a NASA satellite and an asteroid.

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An unmanned spacecraft is now 
in orbit around an asteroid.

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It's supposed to teach us 
about these giant rocks,

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and perhaps help scientists to figure out

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how to protect us from a possible collision.

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That is our Trajectory Manager

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who was making, he and his team, 
most of the calculation.

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(CNN Video)

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And this is the Senator of Maryland.

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And now I am showing you 
the next episode,

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after we were in orbit for a year.

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We had charted the entire asteroid.

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We were familiar 
with every little corner

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and every little crater.

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And we just had a little bit of fuel left.

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And we said, "What are 
we going to do now?"

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Because to maintain a spacecraft
in orbit around an asteroid

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that has this kind of shape, 
like a potato,

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it's very hard and you have 
to really keep pushing

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and adjusting the orbit by using fuel.

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And we were at the end of the fuel.

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So what would happen is that 
the spacecraft would drift away.

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So what we did is, I went to NASA

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and persuaded the administrator that

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we were going to try to easy down
on the surface of the asteroid.

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He eventually agreed to let us do it.

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So the day came, again it was 
as I mentioned the year later.

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We had already calculated what 
the trajectory was going to be like.

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What you see here is 
the calculated trajectory,

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[it] is the black line.

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And the points are the real-time data.

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We had the laser altimeter 
that measured

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the distance of the spacecraft 
from the ground

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by signing a laser, 
getting the reflection

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and measuring the distance with 
the precision of about a centimeter.

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So we knew what was happening.

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And we figured that it would take about 
45 minutes to get down to the ground.

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It seemed like it was going very well.

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I will show you a simulation
of what we had done

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with the spacecraft as you see it.

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And in fact, the spacecraft landed

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with the solar panels pointing 
in the direction of the Sun,

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with the antenna pointing 
in the direction of Earth,

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and we kept getting data.

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And it went on for a number of days.

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What you see is the pictures 
that were taken by the spacecraft

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as it was moving into closer 
and closer to the surface of Eros.

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And at the end we had a resolution
which was actually quite good.

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You can see here, 
this is the last image we had.

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You can discriminate and see rocks

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that were of the order 
of a few centimeters across.

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Well, that wasn't all.

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We had the opportunity 
to do other things.

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This is the announcement 
that we had actually landed.

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And Mr.Goldin, who was 
the NASA administrator at the time,

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was exceptionally anxious because

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NASA had just crashed 
a spacecraft on Mars a month before.

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And he was very worried about 
what was going to happen,

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if this happened again, 
to NASA's reputation.

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But he was very happy.

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Then, I wanted to show you 
another thing, here,

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about the details of the surface.

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There is a crater

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that the International Astronomical Union

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in its wisdom decided to name Hios,

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which was the love child of 
Poseidon and the nymph Hiona.

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So we have a crater on Eros 
by the name of Hios.

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Nothing to do with the fact 
that I am from Chios, mind you.

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(Laughter)

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The most important thing, however, 
is that we finished the project

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and we didn't spend all the money.

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Which had never happened 
in the history of NASA.

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We had a little ceremony,

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the down payment to NASA of
the remainder of 3.6 million dollars.

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In the end we gave them 
back about 30 million.

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Needless to say, we got a lot of abuse
from my other colleagues at NASA centers

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who said, "You never give back 
money to the government.

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"Shame on you", and so and so .

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But we overcame.

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Now let me tell you about the other part

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of the things that go 
on uncharted waters.

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What you see here is 
a view of the solar system.

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Each one of our planets 
of the solar system

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has already been imaged by spacecrafts.

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The four planets you see here,

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Jupiter, Saturn, Uranus, Neptune

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are all, of course, pictures 
from the Voyager mission.

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The Voyager mission started 
in 1977, ladies and gentlemen.

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It was 36 years ago, 
in a couple of months.

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The original plan was to go 
to Jupiter and to Saturn.

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It was going to be a four year mission.

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But then it turned out that it was possible

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using gravity assist 
from Jupiter to go on to Saturn,

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but then also using gravity assist

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from Saturn to go on to Uranus

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and from Uranus to Neptune.

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00:13:05,560 --> 00:13:08,266
And that's exactly what 
we did with Voyager 2

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while we sent Voyager 1 
away from the Sun

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and towards the north ecliptic.

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That was a very well planned program,

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it worked well, it provided 
essentially all new information.

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And I just want to show you

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the spacecraft which 
is about this size.

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This is the antenna,
it points in the direction of Earth.

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It transmits information.

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These here is the instrument 
from my team.

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And I am pointing it out loud

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because it did some other things 
that we were very proud of.

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I am showing you this picture

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with President Herbert Walker Bush.

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Not the new one,
not the son, the father.

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He had a lot of brains, the father.

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(Laughter)

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He invited us to the White House

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as had done Mr. Reagan before him.

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And I am showing you 
that simply because

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to point out that the American 
government, the politicians,

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really appreciate what science 
does for the country.

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And it is not just NASA,

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it's the National Institute of Health,

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it's all kind of national science foundations.

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And they show it. Effectively.

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With this kind of things,

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by inviting us to lunch, 
and things like that.

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Anyway. This, after Voyager went 
past all these four planets.

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This is a simulation, 
that I am showing you,

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where it was moving away 
from the Sun

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passed the last planet, 
the orbit of Pluto.

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And we expected that someday

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we were going to run into this boundary

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and then eventually 
cross another boundary

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that would lead us into the galaxy.

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The problem was that nobody knew
how far these boundaries were.

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We were sort of going in blind.

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There were suggestions that it could be

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a year away, five years away,
ten years away.

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Nobody really knew.

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So, how to find it out?

250
00:15:35,142 --> 00:15:38,123
We had four instruments 
that were working.

251
00:15:38,123 --> 00:15:43,794
This is the one that I pointed out 
before, our team had built.

252
00:15:43,794 --> 00:15:45,618
And another thing that we did

253
00:15:45,618 --> 00:15:47,717
is to put a little stepper motor

254
00:15:47,717 --> 00:15:51,024
that rotated the entire platform 
back and forth.

255
00:15:51,024 --> 00:15:53,755
I'll show you a very short video.

256
00:15:53,755 --> 00:15:54,858
(Buzzing sound)

257
00:15:54,866 --> 00:15:59,681
That is the kind of sound it made 
in the laboratory, when it rotated.

258
00:15:59,681 --> 00:16:03,478
I did this little video for the press

259
00:16:03,478 --> 00:16:08,684
right after the Neptune encounter.

260
00:16:08,916 --> 00:16:13,141
I did have hair at one time, you noticed? 
(Laughter).

261
00:16:13,940 --> 00:16:18,086
We had this little stepper motor

262
00:16:18,086 --> 00:16:19,916
that was rotating the detectors.

263
00:16:19,916 --> 00:16:22,927
Just like this simulation shows.

264
00:16:22,927 --> 00:16:24,498
And you see the colors here.

265
00:16:24,498 --> 00:16:28,056
You can't see them 
because of these lights.

266
00:16:28,056 --> 00:16:32,993
But by rotating around 
it was possible for us

267
00:16:32,993 --> 00:16:40,634
to measure the speed and the direction 
of the hot wind from the Sun,

268
00:16:40,634 --> 00:16:48,332
which moves at the speed of about
1.5 million Km per hour.

269
00:16:48,332 --> 00:16:51,364
Now, you say, "OK, you told us 
about these instruments,

270
00:16:51,364 --> 00:16:54,591
what did you find by rotating this?"

271
00:16:54,591 --> 00:16:55,684
What we found...

272
00:16:55,684 --> 00:16:59,357
Here it is, we kept going 
and going and going.

273
00:16:59,357 --> 00:17:02,685
The idea was that once 
we cross this boundary

274
00:17:02,685 --> 00:17:04,692
we would be out in the galaxy.

275
00:17:04,692 --> 00:17:08,715
What we found instead
is that we ran into a place

276
00:17:08,715 --> 00:17:14,058
where the solar wind no longer
moved away from the Sun.

277
00:17:14,058 --> 00:17:18,206
And we called that 
the Stagnation Region.

278
00:17:18,206 --> 00:17:21,838
We published it in 2011.

279
00:17:21,838 --> 00:17:24,683
It was not predicted by theory.

280
00:17:24,683 --> 00:17:30,016
However some models were suggesting 
that what happens to this wind

281
00:17:30,024 --> 00:17:34,849
is that it goes to the north direction
towards the ecliptic pole.

282
00:17:34,914 --> 00:17:38,879
Our instrument, however, 
was only rotating in one plane

283
00:17:38,879 --> 00:17:42,271
and we couldn't measure 
the speed up and down.

284
00:17:42,271 --> 00:17:45,703
So, I asked the engineering team,

285
00:17:45,703 --> 00:17:50,900
I said "Why don't we turn the spacecraft 
90 degrees, now and then?

286
00:17:50,900 --> 00:17:53,685
And then we can measure 
the north-south direction."

287
00:17:53,685 --> 00:17:56,251
Mind you, this is a spacecraft

288
00:17:56,251 --> 00:18:01,162
that had been in space 
for 34 years already.

289
00:18:01,162 --> 00:18:05,085
And it is just like getting 
a dog that's about to die

290
00:18:05,085 --> 00:18:07,385
trying to teach him new tricks.

291
00:18:07,385 --> 00:18:09,680
However, what happened is

292
00:18:09,680 --> 00:18:13,330
that we were able 
to send the commands,

293
00:18:13,330 --> 00:18:14,918
and by guiding the spacecraft

294
00:18:14,918 --> 00:18:18,097
it executed every command perfectly.

295
00:18:18,097 --> 00:18:21,835
And for two years we have been 
doing this every two months.

296
00:18:21,835 --> 00:18:24,686
We rotated the spacecraft 
in this direction.

297
00:18:24,686 --> 00:18:28,223
What we found out is that, in fact,

298
00:18:28,223 --> 00:18:30,456
even this model was also wrong.

299
00:18:30,456 --> 00:18:34,021
There was no flow of the wind 
in the north direction

300
00:18:34,021 --> 00:18:36,086
or in the south direction 
for that matter.

301
00:18:36,086 --> 00:18:39,381
So theory failed us again.

302
00:18:40,420 --> 00:18:44,868
We actually wrote this up
and were publishing it

303
00:18:44,868 --> 00:18:50,838
until we found something very strange
that happened last year.

304
00:18:50,838 --> 00:18:53,495
What you see here,

305
00:18:53,495 --> 00:18:56,936
and it is the only data that I will show you,

306
00:18:56,936 --> 00:19:01,704
is the curve for cosmic rays, the intensity.

307
00:19:01,704 --> 00:19:09,973
And you see that they started increasing
right about early May of 2012.

308
00:19:10,009 --> 00:19:12,826
These are the so-called 
Galactic Cosmic Rays.

309
00:19:12,826 --> 00:19:18,678
These are particles that were actually 
generated by explosions of Supernovae

310
00:19:18,678 --> 00:19:21,895
millions of years ago
in the vicinity of the Sun,

311
00:19:21,895 --> 00:19:25,939
and were coming from outside 
the galaxy into our solar system.

312
00:19:25,939 --> 00:19:28,124
And they began to go up.

313
00:19:28,124 --> 00:19:32,923
And then, eventually, 
at about the same time,

314
00:19:32,923 --> 00:19:35,711
after two or three increases,

315
00:19:35,711 --> 00:19:38,869
the material that was coming from the Sun,

316
00:19:38,869 --> 00:19:43,419
never mind what these are, protons and 
heliums and what we have here, oxygen  

317
00:19:43,419 --> 00:19:45,146
dropped at the same time.

318
00:19:45,146 --> 00:19:48,292
In other words, 
the solar material disappears

319
00:19:48,292 --> 00:19:50,547
and the stuff that was supposed to be coming

320
00:19:50,547 --> 00:19:52,927
from outside the galaxy 
-- that's what we believed --

321
00:19:52,927 --> 00:19:55,794
appeared and increased.

322
00:19:55,794 --> 00:20:01,960
So we said, "Aha! We actually got out of 
the solar system and into the galaxy!"

323
00:20:02,016 --> 00:20:03,888
But we lacked some data.

324
00:20:03,888 --> 00:20:06,564
This is a picture from a press event

325
00:20:06,564 --> 00:20:10,225
at the Jet Propulsion 
Laboratory in Pasadena.

326
00:20:10,225 --> 00:20:13,270
We were trying to interpret the data

327
00:20:13,270 --> 00:20:16,756
a few days after 
we had made that observation.

328
00:20:16,756 --> 00:20:20,086
Here we have the model 
of the spacecraft.

329
00:20:20,086 --> 00:20:23,532
But we didn't have 
all the data that we needed.

330
00:20:23,532 --> 00:20:28,282
Namely, we couldn't measure the density
of the atmosphere of the galaxy,

331
00:20:28,282 --> 00:20:30,471
if I can put it that way.

332
00:20:30,471 --> 00:20:35,142
Until April of this year.

333
00:20:35,142 --> 00:20:36,687
I don't know if you can hear the sound,

334
00:20:36,687 --> 00:20:39,882
maybe you can turn it up a little bit?

335
00:20:39,882 --> 00:20:41,295
(Whistling sound)

336
00:20:41,295 --> 00:20:44,747
OK. Now, what are these,

337
00:20:44,747 --> 00:20:49,008
is, we have some antennas on the spacecraft.

338
00:20:49,008 --> 00:20:52,661
And in the vicinity of the spacecraft
something happened

339
00:20:52,661 --> 00:20:56,011
and all these electrons 
began to oscillate back and forth.

340
00:20:56,011 --> 00:20:57,956
When the electrons oscillate 
in a magnetic field

341
00:20:57,956 --> 00:20:59,792
they produce sounds.

342
00:20:59,792 --> 00:21:02,358
And when they produce this sound

343
00:21:02,358 --> 00:21:07,086
we are able to determine 
the density of the material

344
00:21:07,086 --> 00:21:08,480
around the spacecraft.

345
00:21:08,480 --> 00:21:13,423
What you see here is that 
we were able to determine

346
00:21:13,423 --> 00:21:17,767
that it was 0.1 per cubic centimeter.

347
00:21:17,767 --> 00:21:19,347
You would say, 
"What does that mean?"

348
00:21:19,347 --> 00:21:24,049
Well, it was 50 times 
what we had before.

349
00:21:24,049 --> 00:21:28,776
When we were in the solar wind,
inside our solar atmosphere.

350
00:21:28,785 --> 00:21:31,567
And because most models predict

351
00:21:31,567 --> 00:21:35,330
that the density in the galaxy is about 0.1,

352
00:21:35,330 --> 00:21:38,865
we knew that we had actually arrived.

353
00:21:38,865 --> 00:21:46,449
So, we had a meeting at my lab
back in Johns Hopkins in September.

354
00:21:46,524 --> 00:21:50,089
We looked at all the data 
and we finally decided

355
00:21:50,089 --> 00:21:53,588
that it was safe 
to issue a press release

356
00:21:53,588 --> 00:21:59,128
that actually we had crossed

357
00:21:59,128 --> 00:22:05,687
the boundary with the galaxy
on August 25 of 2012.

358
00:22:05,687 --> 00:22:09,100
So, think about this:

359
00:22:09,101 --> 00:22:11,785
a hundred and ten years ago,

360
00:22:11,785 --> 00:22:14,880
it was when the Wright brothers

361
00:22:14,880 --> 00:22:19,068
flew a... you could call it an airplane

362
00:22:19,068 --> 00:22:21,881
-- that's what they called it --

363
00:22:21,881 --> 00:22:25,221
at an altitude of few meters
for about 30 seconds.

364
00:22:25,221 --> 00:22:28,664
And then about 50 years later

365
00:22:28,664 --> 00:22:33,527
there was the launch 
of the first Earth satellite, Sputnik.

366
00:22:33,527 --> 00:22:38,423
It went outside the Earth's 
atmosphere for the first time ever

367
00:22:38,423 --> 00:22:42,189
in our history, in humanity's history.

368
00:22:42,189 --> 00:22:49,114
And it got to an altitude 
of 946 km, to be exact.

369
00:22:49,114 --> 00:22:54,932
And then another 55, or so, years later,

370
00:22:54,932 --> 00:22:58,731
we had the exit of the first 
spacecraft, Voyager 1

371
00:22:58,731 --> 00:23:07,604
from the atmosphere of the Sun
at an altitude of 18.2 billion kilometers.

372
00:23:07,604 --> 00:23:09,479
To give you an idea:

373
00:23:09,479 --> 00:23:12,191
the signal that we get from Voyager,

374
00:23:12,191 --> 00:23:15,130
when it leaves Voyager, 
it travels with the speed of light,

375
00:23:15,130 --> 00:23:20,148
and it takes 17 hours and 20 minutes
to get from there to Earth.

376
00:23:20,148 --> 00:23:24,313
The light from the Sun to come to Earth
only takes 8 1/2 minutes.

377
00:23:24,313 --> 00:23:27,547
So you can imagine 
how far this spacecraft is.

378
00:23:27,550 --> 00:23:31,986
To give you the bottom line, so to speak.

379
00:23:31,986 --> 00:23:35,025
Here we are. 
Voyager 1 is in the galaxy.

380
00:23:35,025 --> 00:23:38,212
Voyager 2 is not there yet, 
it is a little slower,

381
00:23:38,212 --> 00:23:42,080
so we expect it will go out at some point.

382
00:23:43,590 --> 00:23:48,088
Finally, I can imagine that 
there was a rooster there

383
00:23:48,088 --> 00:23:50,701
that said "People of Earth, 
welcome to the galaxy!",

384
00:23:50,701 --> 00:23:52,384
(Laughter)

385
00:23:52,384 --> 00:23:55,147
on August 25, 2012.

386
00:23:56,387 --> 00:24:01,047
I posed the question in the beginning: 
"Are there limits?"

387
00:24:01,234 --> 00:24:06,902
I think you can imagine that my answer 
to that is "No, of course no."

388
00:24:06,902 --> 00:24:12,314
I think limits constrain our imagination

389
00:24:12,314 --> 00:24:16,093
and retard progress, I think.

390
00:24:16,101 --> 00:24:20,263
So, we don't need any limits.

391
00:24:20,263 --> 00:24:21,551
And there are none.

392
00:24:21,554 --> 00:24:23,134
Thank you very much.

393
00:24:23,134 --> 00:24:31,761
(Applause)