My name is Nancy Chabot. I'm a planetary scientist here in APL in the space
exploration sector and I'm really pleased to be here today to talk to you
about the dart mission on behalf of the large dart team dart is the double
asteroid redirection test it's going to be the first mission to demonstrate
asteroid deflection with kinetic impactor technology so the spacecraft is
going to impact the asteroid and that's going to deflect it sort of changing its
position in its future path this is the sort of technology that you would use if
an asteroid was potentially on a collision course with the earth and you
wanted to deflect it to keep that from happening
APL is leading this mission building this mission for NASA and we have a
number of partners here also contributing shone down along the bottom
of that slide there to go into a few more details about the mission overview
and what the mission is about and when it happens the launch window opens in
July of 2021 and the impact would happen in September of 2022 now the target for
the Dart mission is the didymus asteroid system named it oboes and it's important
to state upfront that did almost is not a threat to the earth so this is not a
threat to the earth this asteroid is not on a collision course with the earth
this is a good way to do this first test to demonstrate this technology and
didymus is actually to asteroids a binary asteroid system or a double
asteroid system if you will hence the name of the mission double asteroid
redirection test and the dart target is the smaller of the two asteroids so
there's a large asteroid called didymus a 780 meters in diameter and then this
with smaller asteroid this 116 meter did a Mosby that goes around the main
asteroid every 12 hours and so the start spacecraft is going to come speeding in
at over 6 kilometers per second a few days ahead of time there's a CubeSat
that gets kicked off it's contributed by the Italian space agency it's named
aletheia cube and it'll take a few images of the impact but the dart
spacecraft will impact did a Mosby and it will deflect it it will change its
path around the larger asteroid so this is a very safe and effective way to do
this first test of deflecting changing the path of an asteroid but the critical
measurements are not going to be made by the spacecraft itself it's actually
gonna be made from earth-based telescopes and so the earth-based
telescopes are going to be able to see how much we've changed its path
currently it's going at about twelve hours it goes around the main asteroid
we think we're gonna change this path by about ten minutes but figuring out that
exact number is what the dart mission is gonna do so the goals of Dart are very
simple or straightforward it's to target this binary asteroid system to cause a
change to the orbital period of ditto must be going around did at most a and
then to measure that from the earth-based telescopes but at this point
I kind of like to take a step back and address the question about do we really
need something like Dart and to start that discussion I like to show this
little video so this is about the cella Binks event that happened in 2013 so
there's this fireball exploded over Russia and in 2013 here you see tell you
being Russia coming into view it's a city in Russia with a population of over
a million people and without any warning in February of 2013 meteor came towards
this city and exploded in the skies over this city and the shockwave released 20
to 30 times more energy than a world war two atomic bomb spectacular images of
this fireball streaking across the sky captured by dashcam videos in this city
in permanent replaces shattered windows across six city has hospitalized
hundreds of people and so you can see that this is you know one example of
these objects hitting the earth Charlie bass is not really that unique though so
this is a map of small asteroids that have hit the earth for roughly the last
30 years and tell you Binx is the largest one that's happened in the in
that amount of time and you can see it here on this map is that red dot in
Russia but but you'll also see there's a lot of other dots on this map this is
not necessarily a unique event things are hitting the earth all of the time
now telly Binks is before it hit the earth it's estimated to have been about
20 meters in size and a lot of times when people think about asteroid impacts
they think about the one that killed the dinosaurs right and so this is a very
different scale of object that we're talking about so down on the bottom
right corner is some text about this dinosaur killer asteroid and it was 10
to 15 kilometers in size and I'm happy to say that we are tracking all those
asteroids NASA is tracking all of those asteroids and there are none of that
size that are on a collision course with the earth so we're safe from these
extinction level dinosaur killing event but there's a lot of space between the
shell Eubanks size of 20 meters and these dinosaur killers of 10 kilometers
these few hundred meters objects and in fact one of these fell in Tunguska
Russia in 1908 and it was estimated to be between 60 to 190 meters in size so
the sort of few hundred meters and it leveled forests as if they were just
matchsticks blown over when this occurred and this sort of event happens
every few centuries and so it's sort of these hundreds of meters diameter
objects that were really concerned about and this population we actually think
we've only discovered a third of the objects this size that are out there and
so there's actually two thirds of this asteroid population that we're not sure
where they are what would something like this do if it actually hit the earth
well Barringer crater meteor crater in Arizona is a nice example maybe some of
you have been there they have a great visitor center it's a beautifully
preferred impact crater just outside like near the Grand Canyon sort of area
and you can see that impact crater there so this is believed to have formed from
about a 50 meter asteroid that was made out of metal so very very dense asteroid
lots of energy 50,000 years ago hit into this region of Arizona and it made a
crater which is really nice it's about a kilometer in diameter a few hundred
meters deep but the devastation caused from event like this is much bigger than
just the crater that you see today and that's shown from this model of what the
devastation would have been over on the right side the fireball extending out to
ten kilometers large animals killed or wounded 224 kilometers hurricane force
winds out to 40 kilometers and then you can take this same map and overlay it on
DC and you can just get a scale of what a devastating natural disaster event
this would be particularly in a heavily populated area consequently because of
this potential threat from the asteroids that are out there there was a National
Academies study that was commissioned it's called defending planet Earth so
that was in 2010 and they looked at this threat and they said what is the main
things that we should do and their recommendation for the highest priority
mission to do is to do this kinetic impactor technology demonstration
exactly what dart is doing and this graph here graphic from that report sort
of illustrates that the y-axis is the size and we've been talking a lot about
the size but the x-axis is equally important and that's
warning time that you have to deal with this threat because the idea with all of
this is definitely not to disrupt it but to deflect it so you're not trying to
disrupt this object you're trying to give it a small nudge and have lots of
time for this small nudge to add up to a Granger change of his path avoiding a
future collision with the earth if you have a large object which is the top of
that graphic you need to give it a pretty big nudge even just to make a
little bit of change in its position but these are the dinosaur killers these are
the ones that are not really the threat that we're concerned about it's this few
hundred metres range of population where we think that there's about 5,000
potentially hazardous asteroids of sort of this 100 meter size these PHAs on the
graph there and that's where a kinetic impactor technology was judged to be the
most mature and technology that you might want to do if one of these things
was on a collision course with the earth and dart you can see is very well
situated on this graph sort of shown as that dotted blue line going across there
this 160 meter object that we're targeting is right where you want to
test this kinetic impactor technology what's 160 meters I like to show this
little fun graphic just to sort of like bring everybody in the size because
sometimes you talk about these scales and they don't really mean very much so
160 meters is you know diameter is bigger than the Statue of Liberty
smaller than the Eiffel Tower it's kind of the size of a Great Pyramid or maybe
a sports stadium or something like that so you can kind of think about the Great
Pyramids hurtling towards the earth you know it's not a giant object you know
the main did a most a that we're not going to impact is much much larger but
it's still sort of a considerable amount of mass and size and didymus really is
the ideal target and not just because it's the right size that I've been
talking a lot about but because of this double asteroid system because we're
going to change the path not around the Sun but around this other asteroid so
the dart spacecraft comes in at over 15,000 miles per hour and it's going to
try to hit dinner mosby nearly head-on and you can see the original orbit of
dynamos be in the white line and when you hit it nearly head-on you're going
to change its orbit to sort of that blue line about 1% change in its orbit the
blue lines a little exaggerated but you get the idea hitting this thing head-on
causing a deflection of this asteroid around the main one it's a you know
careful well-thought-out test but what's really important about this double
destroyed tests and being able to do it this way is that the spacecraft is gonna
be totally destroyed it's not gonna be able to measure how much of a deflection
it made when it when this happens instead we're gonna use existing
telescopes here on the earth in order to make that crucial measurement so it's a
very cost effective way in order to do this focused first test of the
demonstration and that's actually why the choice for the impact date is in
September of 2022 because that's when the distance between Earth and the
didymus asteroid system is minimized see if you get the highest quality data from
your existing earth-based telescopes in order to make this crucial measurement
it's very ingenious actually of doing this focused mission in order to
demonstrate this technology for the first time so it's a few other key
technologies that I wanted to just mention briefly on dart along with this
overall kinetic impactor technology and one of the most important ones is the
tammana Smart nav system and so we're targeting the smaller asteroid but you
won't actually be able to tell the difference between the smaller asteroid
and the larger asteroid until the last hour of the mission and so all of this
has to be done onboard to pick out the smaller asteroid in order to try to
impact it into the center in order to make this deflection and so that builds
on a lot of APL decades of missile guidance algorithm development and
experience in order to do that there's only one payload on here it's a camera
named Draco and Draco is modified from Lorri which was on the New Horizons
mission took amazing pictures of Pluto so we're using that technology it's also
gonna be the first flight of NASA's next C ion propulsion engine which is gonna
be more powerful than anything NASA's flown before it's also using these
rollouts solar arrays which are going to be deployed in space and roll out and
when they're deployed they're going to be 19 meters from tip to tip so a pretty
pretty sizable spacecraft there but dart is just one part of NASA's overall
planetary defense strategy you would never just do dart in isolation equally
important is to assess what's out there to keep track of those things to search
detect and track find these new objects that we have yet to discover in our
population characterize these objects so you know what you're dealing with and if
you did have to deal with them plan coordinate this is an international
effort and these are international working groups to deal with these issues
and finally there's mitigate and that's where dart comes in if there is a threat
and you need to be do something about it let's be ready let's do this technology
demonstration now so you would think that this makes a lot of sense but
actually this efforts been growing considerably NASA's planetary defense
coordination office which leads this effort was only established in 2016 and
so before there there was a few activities going on but they weren't
very well coordinated so since then nASA has taken a much more concerted approach
and dart is the first spacecraft mission that's being flown by NASA's planetary
defense coordination office hence NASA's first planetary defense mission so along
with this planetary defense coordination office getting set up for NASA there's
been really increased visibility for planetary defense at the top levels of
NASA so this is the NASA Administrator attending the International Academy of
astronautics planetary defense conference held just down the road here
a few months ago and stressing he did the opening address which was also
broadcast on the web and so worldwide people were watching this stressing the
fundamental importance of planetary defense efforts to our planet and at
this conference it was much more than just NASA this really is an
international effort there were more than 250 attendees from 20 plus
countries and dart was very well represented we had a number of
presentations that went over well but one of the unique things about this
conference is there's an exercise that's done so a hypothetical asteroid impact
coming towards the Earth and by day five I've shown what the graphic looked like
up there there was a 60 meter object headed towards Manhattan and it was
going to be a thousand times more powerful than the bomb that was dropped
in Hiroshima and so you can see where this would be a very big natural
disaster if it happened just to reiterate that point and this conference
had not just scientists and engineers but policymakers people from FEMA people
from the press talking about how you would communicate these sorts of events
and so planetary defense as a whole as a topic is really increasing in the
efforts both within NASA and internationally so dart is an important
demonstration of this kinetic impactor deflection technology but it's also sort
of pioneering the way for these future planetary defense efforts in a field
that's really growing right now I know I feel privileged to be part of the dart
team that's working on this to make the first planetary defense mission or
reality thank you
you