Judy: There has been a lot of
anticipation today around nasa's
first ever attempt to strike an
asteroid and knock it off
course.
>> Nasa today pulled off a
historic first.
Take a look at this.
[Cheering]
>> Awaiting visual confirmation.
>> This is video of the exact
moment when nasa's dart
spacecraft crashed into that
object 100 million miles away.
We'll talk with science
correspondent miles o'brien in
a moment but first here is his
report on what nasa was
attempting with this mission.
Reporter: Planet Earth is
practicing defense.
David and goliath style.
A spacecraft the size of a
vending machine is hurtling
toward a kamikaze dive into an
asteroid the size of a great
>> Dart is the biggest engineers
dream ever.
Reporter: Elena Adams is the
systems engineer for the double
asteroid redirection test or
dart.
It's a 330 million dollar1 nasa
mission designed at the Johns
Hopkins' applied physics
laboratory in laurel, Maryland.
Laboratory in laurel Maryland.
Launched in November of 2021,
dart is nearing the end of a 107
million mile journey to the
asteroid didymos.
>> Our job is to go hit an
asteroid.
That's a very specific job for
planetary defense.
Reporter: Their target is
actually the asteroid's moon
dimorphos. Dart is programmed to
auger in at 14,000 miles an
hour.
Engineers hope the 1300-pound
spacecraft will nudge the 5
billion ton dimorphos into a new
orbit.
Dimorphos is not headed toward
Earth.
It's just a test.
>> This is the first time in
human history we have set out to
change the orbit of a natural
object in space.
Reporter: Lindley Johnson is
nasa's planetary defense
officer.
>> The orbit of an object is
determined by the velocity at
which it is orbiting.
So if you just shave less than
1% off that speed, you have
changed the orbit and forever
altered where that object will
be in space in the future.
Reporter: Our planet gets grazed
and hit by asteroids all the
time.
Most offer harmless thrills for
stargazers, but the bigger ones
are a different story. In 2013,
a 60 foot asteroid exploded
about a hundred thousand feet
over chelyabinsk, Russia. About
1500 were injured by shattering
glass.
Over the epochs, much bigger
asteroids have triggered mass
extinctions, including most
infamously, the dinosaurs 65
million years ago.
Planetary scientist Nancy Chabot
is coordination lead for dart.
Is it is it accurate to say
it's inevitable over the course
of time that there will be some
rock of relatively big size,
which has our number on it?
>> This is going to continue in
the future.
It is sort of a cosmic
inevitability at this the good
point.
News is of the asteroids that
we're tracking, there are no
known threats.
But this is also why we need to
find all these asteroids and
figure out where they are.
Reporter: In 2005, congress
directed nasa to find 90 percent
of potentially hazardous near
Earth objects 460 feet or larger
by the end of 2020.
So far ground-based surveys have
found all the planet killers
they can see, but only about 40%
of asteroids big enough to wipe
out a city.
At this rate, it would take 30
years to approach the finish
line.
No matter how hard they try,
they will never cross it using
only ground based telescopes.
>> There's a whole half of the
sky we're not looking at.
Because basically the glare of
the sun prevents you from
looking at very easily.
Reporter: Astronomer Scott
Sheppard is a senior research
scientist at the Carnegie
institution for science.
>> The ones that are most
concerning our the ones that
spend almost all their time in
the daylight, that just get up
to where Earth's orbit is or
just barely cross it.
So the vast majority, their time
is in the daylight.
Reporter: Sheppard is using the
national science foundation's
blanco telescope in Chile to
look for the holy grail of
astronomy.
Planet X.
He decided to point the lens
toward the sun at twilight to
see if he could see any near
Earth objects.
>> It is a hard thing to do.
Reporter: So when you looked,
you saw some objects that are
hiding in broad daylight.
>> We found several near-earth
objects in the survey now that
have not been found from other
surveys, and they're fairly
large objects.
These are planet killers.
Reporter: It is possible in this
scenario we could only have days
to act.
Is that possible?
>> We're really not monitoring
the daylight side of the Earth
very well.
If something is approaching us
from that distance, it would be
very hard to find it.
It might even hit us without
even seeing it.
Reporter: A dart style mission
would have to impact years in
advance to knock an asteroid off
a collision course with Earth.
Astronomers say the solution is
a space telescope called neo
surveyor.
It is designed to orbit between
the Earth and the sun using a
wide-field infrared camera to
identify potential threats that
that we cannot see on Earth.
Congress may have mandated nasa
find the most hazardous near
Earth objects, but it did not
appropriate specific funding. 17
and so the billion dollar
mission is floundering.
The Biden administration just
delayed it two more years.
>> It all comes down to the
priorities of what nasa has on
its plate.
It has more things it has been
asked to do than the funding
that's been appropriated.
>> Shouldn't we be spending
money on surveying before we
practice changing the orbit of
an asteroid?
>> Certainly you got to find
them first.
Reporter: But the orbit of
didymos and dimorphus brought
them close enough to Earth to
create this target of
opportunity now.
It is a complex technical
challenge.
The target is only about 525
feet across, too small for the
spacecraft to see until the last
minute.
When are you going to see it?
>> We don't know.
Maybe as early as 80 minutes
prior to hitting it.
Maybe as late as 35 minutes.
Reporter: So this entire journey
comes down to really in 35 to 80
minutes time, this spacecraft
has to identify this tiny little
Rock and hit it right where you
want.
>> Yes.
Reporter: What could go wrong
with that?
>> Nothing.
It's going to be great.
Reporter: The spacecraft is
equipped with a powerful camera,
smart software and advanced
avionics able to autonomously
identify and
home in on didymos - but then
switch to dimorphos once it
comes into view.
Dimorphus orbits didymos roughly
every 12 hours.
Team dart hopes to speed it up
by at least 73 seconds. 24 to
see if it works, astronomers
will point a few dozen
telescopes on every continent
and in space at the asteroid.
Planetary astronomer Andy Rivkin
is a lead investigator.
Newtonian physics would tell you
this is going to perturb this
rock.
>> Absolutely.
Reporter: So what do we have to
understand further at this
point?
>> We do expect to make a lot of
ejecta, as we call it, when dart
hits.
That also is carrying momentum.
How much bang for the buck are
we going to get?
Reporter: And we can watch the
bang as it happens. Dart is
designed to transmit live images
of its death dive.
Must-see TV.
Ask any dinosaur.
For the pbs newshour, I am miles
o'brien in laurel, Maryland.
>> This is such a tremendous
accomplishment for nasa to have
pulled this off.
Seeing that self-evident joy in
the mission control room tonight
I wonder if you could just for a
moment reflect on this
accomplishment today.
>> I found it rather emotional.
It is rare when you see a crew
of engineers and scientists
involved in space plotting a
crash.
That's number one.
This is a pivotal moment in
human history were now at a
point where we know we could do
something if we were in the
crosshairs of the big rock.
They say getting on an airplane
and people ask what they do,
they have some esoteric endeavor
they are studying in space and
people's eyes glaze over.
When they tell them they are on
this mission they have people's
attention.
There is a level of pride
because what they are doing is
very difficult to think of a
more important mission in space
than this one.
>> Indeed.
The mission here, the idea is
this crash diverts this asteroid
a tiny bit to alter its orbit.
How will they know whether or
not that part of the mission has
succeeded?
>> That's going to take time.
Telescopes be aiming at it.
The reason they chose this
binary system is the little
object that was hit orbits a
larger object we can see from
Earth about every 12 hours now.
When it does do that, when it
passes in front, it dims ever so
slightly, like a mosquito on a
headlight I suppose, but it
still dims and the telescopes
are sensitive enough to register
this.
They had a stopwatch and when it
dims again, they hit the
stopwatch again.
As long as that is faster than
it was before by 73 seconds or
more, they have succeeded.
It's going to take time to
crunch these numbers.
>> As you laid out, this was an
experiment.
This asteroid was not a threat.
What if there was an asteroid
that was a threat and they aimed
a dart like commission and it
missed.
What do we do?
I seem to recall that Bruce
Willis movie where they sent oil
drillers to an asteroid to try
to somehow disable that.
Are there options in addition to
this kind of mission?
>> As an asteroid like this gets
closer, you run out of options
quickly.
The Bruce Willis movie is highly
entertaining but you would never
drill into an asteroid and put a
bomb inside it.
A lot of scientists have been
looking at exploiting a nuclear
bomb offset from the object so
you do not blow it to
smithereens, which is a bad idea
, and you could jar it off
course significantly enough in
time potentially.
Let's hope we just surveyed the
skies so we are not in the
situation.
It is worth the money, I think.
>> I have shot a little bit of
pool.
This seems like a little but of
a bank shot.
No pool balls act unpredictable
ways, but asteroids are not made
of the same kind of material.
>> We know the physics.
We know it is going to move it
at some level.
The question is when that plume
comes out, the ejecta, what will
that do to move it further?
It creates additional boost,
momentum to it.
That is the key thing scientists
are interested in.
How much bang for the buck they
can get.
>> Thank you so much.