hello and welcome to NASA's Jet
Propulsion Laboratory in Pasadena
California my name is Stephanie L Smith
I'm part of the social media team here
at JPL and it's my pleasure to welcome
you to the Cassini NASA social a series
of conversations with scientists and
engineers behind NASA's flagship mission
to Saturn just hours from now we expect
the final transmissions from this
intrepid orbiter but before that we've
got a conversations to have and we've
got a short video to roll for you this
will show you more of what's in store a
lone Explorer
on a mission to reveal the grandeur of
Saturn its rings and moons
after 20 years in space NASA's Cassini
spacecraft is running out of fuel and so
to protect moons of Saturn that could
have conditions suitable for life
a spectacular end has been planned for
this long-lived
traveler from Earth
we have planted the tower
in 2004 following a seven-year journey
through the solar system
Cassini arrived at Saturn sy fern
habituate appointee position light up
the rocket the spacecraft carried a
passenger the European Hagen's Pro the
first human-made object to land on a
world in the distant outer solar system
for over a decade Cassini has shared the
wonders of Saturn and its family of icy
moons taking us to astounding worlds
where methane rivers run to a methane
see where Jets of ice and gas are
blasting material into space from a
liquid water ocean that might Harbor the
ingredients for life
and Saturn a giant world ruled by raging
storms and delicate harmonies of gravity
now Cassini has one last daring
assignment
Cassini's grand finale is a brand new
adventure as it repeatedly Braves this
unexplored region Cassini seeks new
insights about the origins of the race
and the nature of the planets interior
closer to Saturn than ever before
on the final orbit Cassini will plunge
into Saturn fighting to keep its antenna
pointed at as a transmits its farewell
in the skies of Saturn
the journey ends
cassini becomes part of the planet
itself
and there won't be a dry eye in the
house
so to give us a sense of how Cassini
fits into NASA's exploration of the
solar system we have a very special
guest all the way from Washington DC so
please welcome to the house dr. Thomas
is our Buchan associate administrator
for the science Mission Directorate at
NASA headquarters all right dr. Thomas
Zee I'm so excited to be here and
especially talking to the social media
warriors here who are really helping us
spread the word so thanks for being here
and thanks for the work you do talking
about science talk about exploration
stories that are out here which are
ultimately stories about humanity that's
really what this is about
and so Cassini is a really special
mission for NASA I want to just tell you
a few numbers just so you get a feeling
for it at this moment in time we have a
hundred and six missions that are either
operating or in development so that's
the NASA portfolio of these if I looked
at the last six eight months or so and I
looked at the top stories that came out
by audience participation you know like
how many eyeballs are many social media
contacts I looked at the top twenty as
stories or so seventeen of them come
from the science Mission Directorate
there's a lot of there's other parts to
NASA as you know but some of that just
and most amazing stories come from
science out of the 17 and that's the
point where I'm going eight of them came
from Cassini and it's stories that
really moved people and because of that
depth of the type of questions that are
being asked and the questions that are
really we relate to are we alone
questions about where did we come from
those are the very questions that are at
the center of what a planetary science
is all about especially in the outer
solar system so where are we where is
Cassini and as well you remember of
course just a couple of weeks ago
celebrated the 40th anniversary of
another couple missions which are
Voyager that were really the first ones
to zip by at these worlds giving us a
glint of what's to come and two of these
worlds was visited again one of them
Jupiter multiple times over Galileo Juno
is in orbit right now and this one we
visited with Cassini so you see we flew
by with Voyager we visit event into
orbit with Cassini and spent you know 13
years or so in orbit so what's next well
what we're learning and what what you
see from other planets is what we really
want to do is peel back the kind of
cloak of ignorance and and really look
at the next type of questions and what
will happen here is the questions that
are really at the center of what excites
us and the science community that's
coming here requires as a next type of
step perhaps landing perhaps a much
better much higher resolution type of
investigation than what we have done
here so think of Cassini really as a
major milestone on a journey of
exploration where some of the best stuff
is yet to come so for me this is an
ending but like every ending it's really
a beginning it's the beginning of
dreaming beyond it's the beginning of
exploring beyond and really for us to be
excited and motivated to put together
what are the next investigations the
next missions that will come both of
NASA often with contributions from
others or other agencies so for me
that's what Cassini means and so what
I'm gonna do it's just open it up for
questions to see whether you wanna shoot
some rapid questions and see what it was
anything you wanted to chat about that I
missed
yes you talked about questions that are
too calm with the next mission what are
some questions that you would like to
I've answered see the question that
relates to life you know it's a question
that frankly I don't think many people
expected we would be asking in the
context of the outer solar system see
what happens you know sometimes people
talk about research like peeling the
onion
I said that's really wrong because see
when you peel the onion and cut off the
next layer looks a little bit like the
layer before it's just farther any well
the way the nature research kind of
works is like you peel back an onion
where comes underneath is an apple you
peel back an apple what comes underneath
is a a monkey
well behaved so it's basically what
happens is the type of questions that we
unravel are questions that we don't
expect at the beginning so right now if
I had to guess the questions that we
want to look at our questions both about
just the physics and the environment you
know the history of the solar system but
very much life but once we start looking
at that the whole it's not one questions
it's a whole way of investigating that
if you want to look at that
we're peeling it away a new question
will arise in a way that will surprise
us tremendously just like we were
surprised here is very active on Twitter
we have a jam-packed rundown today and
lots of folks to get to so if you have
other questions for the good doctor you
can find him at at dr underscore thomas
z so thank you dr. thomas z thanks so
much
all right so this is a conversation not
a presentation and we want you to be
part of it both the people who are here
in the house at the NASA social and all
of you watching at home or streaming
this live online so go ahead and either
join the conversation by raising your
hand in the house or tagging your
questions on social media hashtag ask
NASA our first panel up today is our
science panel and every mission starts
with science science is the pole star
that guides us it's with us every step
of the way science dictates the
instrument payload on spacecraft and the
maneuvers that it takes during the
mission so today we've got some special
guests and let's welcome them to the
stage
we've got Linda's Pilger the Cassini
project scientist come on up guys join
our little fireside chat here
Jonica moon mean and interdisciplinary
Titan scientist from Cornell Connor
Nixon this year's instrument deputy
principal investigator and morgan Cable
assistant project science systems
engineer now that's quite a mouthful and
I want them to tell you in words that
non-experts
all understand what it is that those
things mean I've asked them all to
prepare and think about a few anecdotes
from the mission and images that were
very very special to them but in the
interest of getting to as many of your
questions as possible we're just gonna
start by having them say what it is that
they do on the mission one after the
other and then we'll go into questions
and if in the answer of one of those
questions you want to call for those
slides then we'll pull them up okay so
Linda I'm the Cassini project scientist
that has been very fortunate to work on
Cassini for almost 30 years and if you
think about that that's the time it
takes Saren to circle the Sun once so I
worked on Cassini an entire Saturn year
and a story that I tell is that my
oldest daughter Jennifer had just
started kindergarten when I was working
started working on Cassini and now she's
married and she has a daughter of her
own so you these long projects can
actually be multi-generational and it's
a wonderful to work with this incredible
team of international scientists
and it's gonna really be sad to say
goodbye well I'm Jonathan Lenin and the
the term interdisciplinary scientist
means that I have responsibility on the
mission for a particular science area in
my case Titan surface what is it made of
how does that interact with the
atmosphere how does it put gases in the
atmosphere and the gases come to the
surface and my role has been during
development to make sure that that
science would get done and then during
the mission to help with deciding which
observations should be done on which
passes of Titan and thanks to the
wonderful discoveries of Enceladus
I've had a chance to work on Enceladus
as well so it's been a remarkable
mission for me the breadth of science
that goes on every day has just been
extraordinary
so I'm Connor Nixon I worked at NASA
Goddard Space Flight Center which
provided the composite infrared
spectrometer that's on Cassini one of
the core optical remote-sensing
instruments I work as the deputy
principal investigator of that
instrument and in fact working on
Cassini has been my entire career so I
started out in graduate school before
the launch of Cassini helping to build
the Sears instrument and then I
continued on all the way through the
launch the Jupiter encounter which was a
very exciting tryout period for Cassini
all the way through to getting in orbit
on down actually doing the science with
Sears which has given us a lot of
remarkable discoveries including the
infrared signatures on Enceladus the
South Pole on the discovery view
molecules and Titan's atmosphere so very
exciting to be working on this mission
hi i'm morgan cable and i haven't been
working on Cassini's for 30 years but a
relatively recent addition but I think
that's one of the wonderful things about
Cassini is that we're able to bring in
people closer to the beginning of our
careers and we can be mentored by some
of these amazing scientists and
engineers my role has been to support
Lynda and the deputy project scientist
as project science systems engineer and
basically help the scientists and the
engineers communicate across the Cassini
mission because oftentimes
in different languages but it's been so
much fun learning and watching this
amazing mission grow and I can't wait to
see what's next this is just one chapter
of Cassini that this is the start of a
new chapter and I'm excited to see what
new discoveries we'll find with the data
analysis to come fantastic okay with
that let's start the conversation do we
have questions for our science panel
just wait for the microphone to come to
you hi thank you technology changes a
lot since Cassini was launched in 97 are
there tools or instruments that you wish
Seanie had on it that are available
today and I guess in that sense that if
you're able to do a return trip to
investigate the moons what would you
most want to put on it to get more
information well I'll start no I don't
wish that any instruments we have today
we're on Cassini because then we'd end
up in this continuous vicious circle of
time travel where we're waiting for the
next terrific instrument the thing about
the Cassini payload is that it was
remarkably broad and deep and yes today
those instruments are obsolete but the
what they were able to do which i think
is one of the most astounding things
about Cassini is that they could
actually follow up on their own
discoveries so let me give you an
example quick one the Cassini radar and
the imaging experiments discovered lakes
and seas on the surface of Titan these
beautiful images but there was a lot of
discussion about where they really
liquid how deep were they what were they
made of the radar system actually was
able to tell us that because instead of
tilting the radar antenna to the side to
make an image it was possible to point
the radar straight down and actually
send signals through these large seas
and some of the lakes and detect the
signal from the bottom of the seas as
well as the top and so we could learn
the depth and then by determining how
much the signal was attenuated or
weakened by its travel we could actually
say something about the comp
so being able to follow up in that way
is really extraordinary now there are
lots of wonderful instruments that we
would all love to fly today back to the
Saturn system but there isn't enough
time to tell you about them another
thing sometimes you get serendipitous
kinds of discoveries and I think one of
them for Titan that helped confirm well
you had liquid in those lakes and seas
was actually to see a specular
reflection if you look at just the right
angle for the sunlight coming down
hitting the liquid coming back up the
visual Manfred mapping spectrometer saw
a beautiful specular reflection once the
sunlight reached the northern lakes and
seas so we could point to that and say
okay that's what you see with the liquid
and then of course probing the depth is
just a further confirmation of what the
composition might be I think if I could
you know for a future mission there's so
many discoveries Cassini's made to
follow up on and that's what's great
about exploration but certainly to a
couple of them to go back to Enceladus
with the instruments possibly to look
for life maybe to land in a lake or sea
on Titan and actually sample and see
what it's made of and could you have
really unusual astrobiology in a methane
sea and of course the Rings are
incredibly beautiful and maybe even for
me to get closer to those rings and
actually see how the particles interact
and collide I think that would be a
great mission a a probe into Saturn's
atmosphere to measure things like noble
gases to you know to depth so many
things we could do to go back and let's
not forget your anus and Neptune maybe
we need to see any like orbiters around
those two worlds - all right I think we
have a question right here in the front
row hi Morgan I think you had a really
good point that this is the first
chapter of the book and there's a next
generation and a lot of us are involved
in education and there's a next
generation of young scientists and you
know even just kids that are in school
that are looking to you and and what
you're accomplishing right now and do
you have something that you might want
to say to them should I start okay well
I think the most fun thing about working
in planetary
science is that there is no single path
to get there I've had some students or
some kids come to me and say okay what
what should I study to come and work at
NASA one day and my answer is you're
following your passion whatever that
happens to be it could be biology it
could be chemistry geology
it could be engineering any of those
paths is the correct path so as long as
you love what you're doing and it
happens to have something to do with
space you'll probably end up finding
your way here so that would be my advice
is pursue your passion and then no
matter what whatever you end up doing
you'll be happy you know it's like to
outdo that by saying that I think that
planetary science is one of the most
remarkable feels to be involved in
because really it's got a place for
everyone it's got a place for chemists
biologists physicists unlike other areas
of astronomy we're studying stars and
galaxies and it really just takes a lot
of physics but in planetary sounds
there's everything there if there's
geology as we've discovered on Titan
there's a place for people who are
oceanographers which we would have never
anticipated outside of the earth so you
can really study almost any field and
then wind up studying our own solar
system and I think that's great I would
add one of the things that I I told my
daughters and and because I heard this
from my mom as well you know don't be
afraid to take lots of math and science
and classes that might be a little bit
harder keep those doors open you know
give yourself as much breadth and
opportunity because you may change your
mind along the way when you go to
college and both my daughters are that
they start out one direction and went a
different direction so keep your doors
open you know that would be my advice
you have another question in the front
row this is a bit of a career centric
question so I apologize in advance as a
concept designer in science fiction has
science fiction inspired or informed
potential usable ideas for you ever I
love to read science fiction yeah
that's a great question I can't think of
an instance where science I think
science fiction has inspired a lot of us
to go into this field and it's always
it's like two sides of a coin where we
have the science that we love and then
on the other on the other side you get
entertained by the science fiction I
certainly think that science fiction has
taken its inspiration from some of the
discoveries that come out of science
around the solar system the you know
Europa report and these sorts of things
but I think that just keeping it up in
mind and being curious really is great
for for both so I'm gonna date myself
one of my inspirations was the other
side of the sky by arthur c clarke which
was a yes i know his eyebrows went up he
wrote it a few years before i actually
read it the thing about it was that it
drew a picture of a progression of space
activities and accomplishments in a very
short number of pages that as a kid
really inspired me because when you're
young you don't get a sense of how time
passes and you know what has to come
before in terms of accomplishments and
it was it was drawing that kind of step
by step story in which this first person
sign is talking about going into space
building a space station and then at the
end of the story
his son is about to leave on a trip to
mars and it it really drew the picture
of that generational approach to space
exploration that impressed me as a kid
and still impresses me today so read it
it's great yeah I'd say I'm a big fan of
Star Trek you know I grew up watching
the Star Trek series and I thought wow
wouldn't that be really cool that
inspired me to be an explorer because
there were so many creative plots and so
many creatures and places that they went
that I really enjoyed Star Trek
creativity in science I think is a
critical element that people who maybe
aren't going to study to be scientists
tend not to realize that this is
something when we're talking about the
potential for life in a methane or
ethane lake on Titan what that might
look like or now we're discovering so
many exoplanets that I mean the
properties there could
pretty much anything that you can
imagine that still fits within the laws
of physics probably exists out there in
the universe somewhere so being able to
use your imagination to try to come up
with as creative of a solution to some
some strange set of conditions that
might exist in the solar system or
beyond is important it's an important
part of our job when we're asking a
question we want to make sure that we're
designing the best experiment to find
the answer and the answer may be really
different from what we might expect well
as the good mr. Spock would say
fascinating are there any other
questions for our science panel here in
the house all right I think we've got
time for one more and then Kendra how we
doing on ask NASA questions online ooh
okay all right we'll do one quick one
and then one from social and and then
any other questions that you have or
that you have later you can tweet those
two at NASA JPL or at Cassini Saturn and
we will get you answers hi I'm from
Johns Hopkins Center for talented youth
and our kids have lots and lots of
questions for you so one of them is how
would Cassini react if it was contacted
by aliens and how would this be recorded
and transmitted and was Cassini designed
to handle that kind of contact
potentially I'm not sure Cassini was
designed to really handle that okay
let's go ahead and go to those social
media questions so can we get a
microphone for you Kendra
Gill Bryce asked what sort of
information do you hope to gather during
the final plunge during the final plunge
we'll have eight of our instruments on
including the island neutral mass
spectrometer that's going to directly
sample Saturn's atmosphere so as we're
going in till the very last second we'll
be getting information back about the
composition and the environment around
the spacecraft well I would just add
that you know there are some very
fundamental questions about Saturn and
its evolution and some of the things
that hopefully Cassini will measure
during that plunge will provide some
answers like the ratio of helium to
hydrogen which we know for Jupiter and
we don't know quite so well for Saturn I
think we have time for one more social
question I roll with Sol asks how far
into the atmosphere is Cassini expected
to survive before breakup not very far
at all
we have just little tiny thrusters
they're about 1/8 pound each and if you
look at there's a half scale model of
Cassini in the auditorium here there's
one on the table it's it's huge so we
think maybe about the level that the
space station orbits is all before he
hit atmosphere that's thick enough to
turn it away and very shortly thereafter
because he able to soon and great and
then basically melt in Saturn's
atmosphere with that let's thank our
science panel
okay you may be wondering what the heck
is up with this monitor that's to my
side or what this gentleman is doing
here you're about to find out
okay so 83 minutes one-way light time
separates us on earth from Cassini at
Saturn and there is no chase plane so
you might be wondering how can I see
where is the spacecraft in relationship
to the planet and what is it doing right
now there's a solution for that and it
is called eyes on the solar system and
here to show us more about the new
Cassini module is one of the people who
made it Jason Craig technical producer
take it away Jason thank you Stephanie
okay so first I want you guys to know
you can download this right now and do
what I'm doing if you have your laptop
go to eyes nasa.gov and click on the
Cassini picture download quick install
it takes like 40 seconds and you're good
to go exactly like what you're gonna see
here okay so this is a 3d real-time
interactive simulation of the entire
Cassini mission and I mean the entire
mission you can watch it in real time
for 20 years I don't recommend that but
you are in charge of time so if you want
to go backwards you want to go forwards
you can do anything you want so I can
let's rewind a little bit I can go to
any point in the mission the dates are
down here there's a lot of talk about
Enceladus on the stage so let's let's
actually go look at Enceladus for a
second so look at the bottom there
there's these fascinating geysers we had
no idea they were there we actually had
to send the mission out there and notice
it so let me light it up for you so it's
just such an incredible thing it's just
so excited to be part of this you can
look at every single pass I'm going to
show you the Cassini carwash right now
so we actually sent Cassini through here
on one of our flybys so if you're really
serious about learning about Cassini we
have every flyby represented here
including 127 Titan flybys so have at it
I'm gonna go to Enceladus and let's go
down to this one e 21 10:28 2015 we
decided to fly right through them go
ahead and turn on the ion a neutral mass
spectrometer which you just heard about
angled so that it's right in the plume
want to confirm without any doubt
whatsoever that this plume is made of
water so we're going to the timeline you
can see the timeline expanding and here
we are back on October 28th 2015 where
we're gonna kind of shoot the plumes
right here so it's gonna go right right
on through so this is actually
spectacular and most people want to know
was there a risk was there any kind of
risk whatsoever so yes we there was a
risk analysis and it was determined that
it was sufficiently small that we should
go ahead and do this and the intimus
instrument is on the corner Cassini and
it's angled right into this stuff so it
went right through sniffed it tasted it
and confirmed that it was in fact water
so there is a subsurface ocean at
Enceladus and it is full of water so you
quickly want to see where Cassini is now
just right here this is a lot this is a
live simulation shot you've got the
distance descent Saturn here countdown
to the end of mission and the speed it's
17,000 miles an hour oh gosh I should
put this on kilometres we don't want to
cater explicitly to the American
audience so all right now we're in
kilometers that's better so this is
where it is now and let's speed up time
spoiler alert this is 30 minutes per
second all of these rotations are
accurate you can see what Cassini does
all the way and let's speed that up a
little more I'm how much time - I am
alright okay so here we go spoiler this
is what's going to happen now I got to
slow down because spacecraft get faster
as they approach and you can see the
speed going way up and this is the
signal that is the speed of light signal
back to earth a data dump and it takes
83 minutes to get there so we don't
really know for 83 minutes so pointing
at earth out that way let me show you
kind of a cool perspective of this from
above so there's the final transmission
right here I want to show you just how
slow the speed of light is it's
ridiculously slow so relatively speaking
so let's let's pull out from let's pull
right on out from Saturn so there we are
this is real time speed of light and it
just crossed the
outer moon is just think about this this
is the speed of light now I'll show you
really how how slow it is let's go above
the solar system you can't even see the
signal that's how slow the speed of
light is going in real-time right here
you can't even see it yet so I actually
have to speed up here this is five
minutes per second so this TS is
transmission start each number means
that's how many minutes you have left of
transmission and now we go back to real
rate so there we are speed of light it
just crossed Jupiter Jupiter's orbit and
it's still very far from Earth and this
is moving this is the speed of light in
real time so it's kind of cool to see
this so three-and-a-half hour
transmission at the end we get at eighty
three minutes later and you can watch
all of this in here along with all kinds
of cool things like the seasons of
Saturn you've probably never seen this
before this is a very very spit up
fifteen year back and forth cycle of the
shadows on Saturn the ring shadows the
Rings cast shadows onto the planet
itself they're gorgeous
and you see where summer becomes winter
and vice-versa
so the year on Saturn is about 29 plus
years it's pretty pretty crazy to see
this sped up so every picture of Saturn
you can go back it's all accurate when
you check it okay let's go back to live
and that's it I'm getting the egg so
eyes NASA gov you can do this for
yourself it's a real-time accurate
simulation we work directly with the
scientists some of whom you've talked to
we use all the real data the same thing
the engineers use thanks very much and
give it a shot
and adjacent before you go NASA eyes is
streaming on NASA's new twitch channel
right yes that's right go to twitch
twitch TV slash NASA it's on there right
now you can watch this view all the way
in
thank you oh right so you have heard
about the science you have seen the
daring maneuvers that Cassini will take
let's hear from the people who are
helping to make that happen
the engineers so please welcome to the
stage our engineering panel which is
made up of Earl maze the Cassini project
manager Julie Webster come on up guys
come on up and join us the Cassini
spacecraft operations manager Lewis
Andrade Cassini guidance and control
engineer and Molly Bittner Cassini
systems engineer welcome engineers just
like our science panel I had them think
about some of their favorite moments
from the mission and they have some
anecdotes and they have some images in
their hip pockets but we want to start
with what it is that they do so I
challenge you to see if you can do this
without using any TL A's no three-letter
acronyms yeah okay it's a throwdown all
right so we're gonna start take it away
Earl why don't you tell me what is it
what is it you do on this I am the k CA
s PR oj m gr I'm the Cassini project
manager before I toss budgets and
schedules around I actually had some
chops and spacecraft engineering the
navigation but no I'm just the project
manager I don't have any pictures but I
thought maybe I'd share an interesting
anecdote because if you know that in
astrodynamics we are just really prone
to killing the holidays fourth of July
Labor Day any time we can make the
flight team work on a three-day weekend
we do and so for probe release wagons
probe release Christmas Eve and we had a
lot of Europeans in town because of
course that was their probe and they
want to make sure that we got rid of it
properly and so that we had a whole
bunch of expats in town and we had
Christmas dinner at my home and it was
just one of the nicest
Christmas meals we've had very simple
but had just international we had people
from France and the Netherlands England
and of course a fair contingent of
Americans as well it was just a great
day all yours okay I'm Julie Webster I'm
the spacecraft operations manager I
first went to work for Earl when he was
when he really had chops when he had
when he was the spacecraft operations
manager I actually started with the
spacecraft in 1995 so I was there for
the first power on I was a test
conductor so I kind of orchestrated the
test as we built up and went through
this is this is what Cassini looked like
when I first saw it
so as a 12-sided hunk of aluminum with
about 10 miles of wiring inside of it
and believe it or not I sat inside that
that hunk of aluminum as we would power
things up because I'm kind of a I guess
I engineer by touchy-feely so I actually
said inside that as we powered things on
to hear what they sounded like and what
they they go through and I was telling
another news crew today that when
Cassini goes in that's what I'm going to
see if I close my eyes I'm going to see
the inside of that 12-sided bag got
another picture of it looking a little
bit more professional so this is what it
looked like as we were building it up
that's a probe probe simulator I think a
lot of the other things were on there
we'd put the high-gain antenna on we
didn't have any of the thermal blankets
on yet I think this was right before we
were getting ready to go up to solar
thermal vacuum and then the next picture
is of course it's it's real picture the
way it looks to everybody else today and
in all its glory and all its glory
Earle tells me those gold Gold's gold
thermal blankets are not as gold anymore
but I said they're pristine in my mind
so that's that that's my part
responsible for the health and safety in
the spacecraft and Molly is an X team
member
almost xt member arrest I've got 10% of
your time and Lewis works for me also so
so yeah my name is Luis Andrade and I'm
the lead guidance and control engineer
for Cassini's very final sequence of
commands and as a guidance and control
engineer pretty much my job is to
determine Cassini's orientation and
space and also to steer Cassini using
the onboard thrusters and reaction
wheels in order to point at different
targets of interest and tomorrow during
the final plunge I'll be in the Mission
Control room at the front console
monitoring real-time telemetry as it
comes down from the spacecraft and
they'll be calling out key attitude
control events as they unfold and for my
quick anecdote could you show my first
image please so I've had a lot of great
moments but I'll tell you about this one
this is an image that Cassini took of
pan and pan is Saturn's inner most moon
and the reason that this is special to
me is because it's the result of an
onboard vector update that yeah that I
did and if we didn't do this vector
update just right pan would have been
completely outside of the cameras field
of view and we would have missed it and
over the years I've done a lot of these
vector updates for Titan and Enceladus
but this one really stuck in my mind
because I remember when these images
started coming down from Cassini the
scientists were just ecstatic they were
so happy at how great these images came
out and I remember at that moment it
really hit me you know I have directly
contributed to a scientific result of
this magnitude and as a young engineer
it was really inspirational to to know
that you know in some way I'm
contributing to Cassini's legacy which
is going to live on long after I'm gone
so can you show the next image so we got
over 50 of these pan images and when you
stitch them all together you get this
really cool video of Cassini's encounter
this is not a simulation this is what
Cassini really saw and that's pretty
much it for me so I'll hand it over to
Molly
all right however
I'm Mollie Bittner I'm on the spacecraft
operations team I'm on Julie's team and
I am a systems engineer which basically
means that I oversee the entirety of the
spacecraft so not just one subsystem but
how they all work together so I actually
have an image two from 2015 so this is
Enceladus is plume so that a lot of the
science team has talked about but to me
this picture represents sort of the
spacecraft as an orchestra right so
that's how I view the spacecraft
all the pieces working together to get
us this beautiful goal that we have so
this was in 2015 and one of the
sequences that I was lead on and I
remember
designing the orbit trim maneuvers or o
teams if you like acronyms leading up to
this flyby and it was a really low
altitude where we just skimmed over the
top of those plumes and we had Lewis's
team guiding the attitude of that flyby
and the navigation team and we had all
the subsystems working together and
that's really what I value on this team
is every different part works so well
together and really seeing it all come
together to deliver this great science
is really amazing all right with that
we're gonna go ahead and open it up for
questions who's got some engineering
questions right here we've had this
question pest off they said we should
ask the engineers not the aliens when I
leave that to you what will happen to
the spacecraft as it enters the top
layers of atmosphere what changes do you
predict will happen in terms of of the
spacecraft well the the thrusters the
little thrusters the little
quarter-pound thrusters that are in each
corner
they were quarter pound to start out
with they're about 1/8 pound now because
of the the pressurization they'll start
fighting the atmosphere and Lewis is
going to call those steps out as we as
we start to fight the atmosphere we up
the data rate to one per second so that
we could get the thrusters as fast as we
could and eventually that's going to be
overcome and we and we'll lose and we'll
lose the ability to point the spacecraft
because it has to be pointed these guys
convinced me that they could they wanted
to go to a half
half half mil radiant we usually
bangbang control at two milliradians but
they said they could hold on to it for
one second longer if we stayed at the
half mil rating you know Miller 88 is
one 17th of a degree so we're pointing
within point O 1 degrees and as soon as
we lose the ability to do that it will
go off and then it'll start basically
disintegrating melting not really
tumbling well I mean yeah like what
Julie said we're gonna be fighting as
long as we can but really we expect to
to lose signal in about 1 to 2 minutes
if we're lucky and we're gonna lose
signal and Ksenia will go on for a few
more moments but essentially after we
lose a signal we we don't know it's
state but you don't expect high rates
you're not going to really be spinning
like gradually drift off point to find a
more stable aerodynamic attitude which
won't be pointing at the earth and in a
minute later and just be vaporized and
and and the atmosphere is gonna make
Cassini more aerodynamic by stripping
away it'll force it stripping away parts
and we yeah we you know setting setting
the attitude in a more aerodynamic
fashion yeah okay let's go ahead and
take some social media questions Kendra
you got some ask NASA questions for us
mark is asking what improvements in
conceit Cassini were made via software
over the last 20 years
well we'll start there there they're a
bunch
first of all Cassini when we launched
didn't have the capability the software
capability to do orbital operations we
had the basic structure and we knew all
the hardware worked but all the control
laws and everything all of the
algorithms to actually say there's
Enceladus turning point and shoot with
the reaction wheels weren't on board
those were all developed during cruise
right right we could not do a record we
knew that we had two recorders we knew
that all the strapping and wiring would
work but the software and smarts to do
that
would was not there so there was the
whole baseline set of software
development that we did during the
cruise but then on top of that the
flight team you know took their own
experiences and did some augmentations
for the software in order to adapt to
some of the changes and idiosyncrasies
you saw on the spacecraft don't let you
to speak to those well there they the
atlo team and the design team actually
punted Durrell's group they said oh
you've got seven years in cruse you're
not doing anything you might as well
rewrite flight software while you're
going out there which was a surprise to
the scientist who thought we were going
to do science going to Venus
so we had three demarcations we had
three main areas that we wanted to
upload so we uploaded in 2000 we
uploaded in 2003 and then as oral said
we made some Corrections in 2007 we made
some major Corrections to fight off a
couple of the things that the
solid-state power switches would
occasionally trip off they had a
flip-flop circuit in there that would
Cajun elite rip off and that's it wasn't
dangerous to the spacecraft but it was
annoying and it cost science so we we
would stop that attitude control
continued because they had to they had
to continue to write you know star
fields and Cassini vectors and Saturn to
Sun vector so what'd you do with that
you so so there were there were three
main revisions that were designed
pre-launch
I mean we knew that and then there were
probably five or six iterations along
the way the last time we did a full
flight software was really 2010 the the
one you've missed it I think maybe the
most telling was that we realized the
spacecraft when it safes
when it gets into trouble and it's
called safety turns off all unnecessary
loads points to the earth says I'm in
trouble calls home well the spacecraft
was wired to do that at five bits per
second at a 10,000 bit transfer frame
you can imagine how long it takes us to
get one frame
limitary back much less the number of
frames we need to diagnose the problem
so these guys figured out pretty quickly
that only in the most dramatic of safing
situations do we not know where the
earth is and so for all those cases they
rewired fall protections so that we
wouldn't use the high-gain antenna at a
very high data rate to bring the
diagnostic signals back and it saved us
it really did that five bits per second
is just an agony if you can't imagine
how smooth that is and so they rewired
it so that unless attitude control was
completely lost we were in a manageable
state and I think that was one of the
biggest changes we knew very very
quickly that we just weren't going to
lock up on the five bits even ten bits
at Jupiter you know that's really hard
to do and you know so there were a
couple questions from the media
yesterday about find out you go to your
low gain and get a longer signal and
that's exactly right
you hold the higher signal and you can
get science data you're getting science
data to the last second so you could
stay with the low gain signal for
fifteen more seconds but it takes 30
seconds for the spacecraft to
reconfigure to the low gate so you're
losing all that science while you're
reconfiguring to hold a maybe signal
going out it was and we've saved twice
since we built that in 2003 and both
times it worked like a charm it was it
was the greatest thing I've ever seen
when the spacecraft went off Sun perfect
point back to earth point and started
dumping down 2,000 bits per second and
we were able to diagnose the problems
very quickly write more questions here
in the house yes we have a very
important go back courtesy Jonathan Lou
Neen from the science panel yeah so I
don't did you hear my question earlier
word the kids are interested in alien
life they want to know you know um so
what's Cassini sort of built with that
possibility in mind I'd say no no no it
really wasn't
I mean Cassini is was built to
investigate the entire electromagnetic
spectrum it was built to do geology was
built to do chemistry but it really
wasn't about about life it was about
meeting perhaps that can the basis for
for life in a sense you know what we've
seen at Enceladus but as a life finder
or something that could discern we I'm
not an astrobiologist but even even
asking that question trying to find
something that could give you a
definitive answer is extremely difficult
and Cassini was more to just do a whole
survey of the system say that's a that's
a long no thank you okay and then we
didn't carry a golden record for for the
Star Trek team they pick up either I
think we've got one more question here
in the front row in the house it's more
of a comment than a question in in
Hollywood it's it's offensive to
name-drop but I'm going to do it right
now I've been very fortunate to work or
some big-name directors James Cameron JJ
Abrams Steven Spielberg that's the name
dropping part and I apologize but I say
that because I'll dare to speak for them
as well because I've spoken enough to
them that you guys are the true
inspiration and the real stars here it's
it's such an absolute privilege to be
amongst you and and your minds I just
want to crawl inside every one of your
skulls and just dance around cuz it's so
fantastic to experience what you're what
you're sharing with us so thank you well
well you you enlisted tell what inspired
you
I kind of was looking for a job when I
found this one
sorry really quick before to answer your
comment there actually last week I was
at Long Beach comic-con and I did a talk
there and it's a science sci-fi
convention and those people were great
they I mean they love science fiction
and they loved hearing about real
science you know space missions like
Cassini and and they go very well
hand-in-hand you know so yeah yeah I'm
with that I grew up watching Star Wars
of course and playing with Legos and
playing with all the alien themed Legos
so there's my alien pun for you but I
just love space in general you know so
anything that space themed I'm a huge
gamer in my spare time and so anything
that has space involved I love and then
that I get to come to work and inspire
people in the past couple of days of
talking to the media has just been such
a privilege right so usually I'm working
with all these great team members and
it's amazing but to be able to be
inspired by you guys to because
sometimes we get wrapped up in our
everyday office you know normal work
that we do but having you guys come here
and say that you're inspired by so that
really helps us go forward one of the
best thing that ever happened to me was
on a different spacecraft we hadn't we'd
had a lot of problems on an earlier
mission that I worked a lot of problems
and we were all stressed out we were
working 12 on 12 off I didn't like them
they didn't like me and you know we were
all just the go away I need sleep and
the project manager at the time wrote us
a letter thanking us for saving the
mission and that what we did was was a
miracle to the average person on the
street and I have never forgotten that
never and and gone back to oh yeah and I
like these people too once I got a few
hours sleep yeah just comment again I we
had an open house here a few years ago
that was overwhelmingly crowded
overwhelmingly hot people were parking
on the freeways and traipsing across
Arroyo to come on
and just reminded us again of how
blessed and lucky we are I mean I'm
walking down the road and it's hot and
everyone's and I hear from the back of
my swim you hey what's it like having
the best
in the world you know oh boy he's right
I do it's really cool and so thank you
so we've very lucky and with that let's
thank our engineering panel okay so on
social media it's pics or it didn't
happen
and thanks to Cassini we've got lots of
pics the spacecraft has taken nearly
half a million of them and here to tell
us more about the awesome images the
last images that we're expecting to be
coming down just hours from now from the
spacecraft we've got one of the people
who put together the sequence that will
take those photos so as our engineers
leave the stage we're gonna welcome to
it Mike Evans ISS team associate from
Kourt Cornell University so come on up
Mike alright thank you well as I've been
introduced I don't have to say Who I am
and what I do I suppose I should just
quickly say you know what I do on
Cassini I I lead one of the teams that
actually allocate allocated time to
actually do the science and that would
that was not not really part of my
imaging job and then for my imaging
imaging job I identify opportunities I
put requests in you know please let us
do this and then I'd argue for them in
the groups that actually allocate the
time or once once we actually get you
know succeed I do I do all the paper
well not it's largely paperwork it's all
done you know online with files but I
make sure that all the eyes across all
the I's are dotted all the T's are
crossed and then I actually helped build
the Poynting design which is where to
point the spacecraft when and in many
cases I actually will build the camera
command you know open the shutter at
this time keep it open for thirty seven
milliseconds use this filter use that
filter and then in many cases when the
data comes down I actually am able to an
time involved in the analysis of of the
actual imaging data and actually you
could bring up my first slide let's see
okay so the other people have been up on
stage today I've told you know that
either there there are no anecdotes or
though are there favorite images well
this is both my favorite image
the anecdotes that I'm actually going to
tell you this is this is the small moon
daftness that orbits right at the edge
of the a ring of Saturn it's only about
eight or nine kilometers across and it
sits in this gap called the Keeler gap
which rady leaves only about 40
kilometers across and it actually it's
it's not there by accident the gap is
there because the moon is there the
moon's gravity actually you know clears
the gap and if you look just to the
bottom left of the moon you you can see
a little whisper material and about the
edge waves and talk about the whisper
material that's all due to the
interaction between the gravity of this
moon and the little ring particles that
are actually just you know part of the
ring just just outside the gap and my
anecdote is this moon misbehaves it
apparently when we look at its orbits
you know it apparently we don't know why
yet but it apparently jumps forward a
little bit and jumps back a little bit
in its orbit but it has the nerve to do
it when we're not looking so when we're
down equatorial and you know the Rings
are edge onto us and we can't see this
moon something has happened on the two
on the last two equatorial periods
something's happen to this moon and it's
jumped a little bit forwards in its
orbit or it's always juggling in one
case you may have jumped a little bit
back and the problem with that is we
have to be very close to get these
high-resolution images and if it's not
exactly the way we think it is if it's
not exactly where we tell the cameras to
point we miss it completely we don't get
any any images at all and that's what
happened to the first observation we had
about two years ago at Christmas we
missed we missed this completely because
the moon had actually jumped and what we
were pointing where we thought it was
not where it actually was so when this
happened back in January of this year we
knew well it's a danger so let's let's
hedge your bets instead of just pointing
where we think it's going to be let's at
least for the commit for these closest
approach images let's actually do a
mosaic let's point let's let's point you
know one frame slightly ahead one frame
a little bit you know further ahead
where we think it is one frame behind
and one frame a little further behind
and as it turns out this image is from
the very first frame it's as far away
then if it had been any further away
from where we thought it was we would
have missed it completely so we actually
only have images from this one footprint
so that we took
so somewhere between 50 and 60 images on
the way in as the as the resolution
increased but we only got it in three
and all three images were pointed at
exactly the same point so even with all
the care that we've taken we almost
missed it but the images that we this we
did get are incredible I mean I tell
people you know you look at this I think
it's it's some sort of art deco object
it's the but it's the hood of a car it's
you know it's something it's it's
clearly not the flying saucer shape that
that pan has that Lewis was talking
about earlier and if you could go on
shore the next image this is just an
example of the of the bedroom of my
bread and butter work I mean this is the
edge of the a ring there's the there's
the F ring you know that the thin narrow
strip and to moon the so-called shepherd
moons either side of it Prometheus
inside Pandora rats outside and the sort
of thing I'd do with this image is I do
astrometry so basically I figure out
where all the stars are in the image
main little Corrections so we know
exactly where the camera was pointed
because even though we tell the camera
points in this direction it's net it
never actually points exactly in that
direction it's usually somewhere between
it's usually about 20 arc seconds off
and those 20 arc seconds or something
like 15 or 20 pixels and that makes a
big difference when you're trying to
figure out orbits so I would you know
figure out where we were pointed there
and write that the the moon is in this
position and that corresponds to this
direction and then that data gets sent
off to people at JPL and they put it all
together into numerical simulations and
then update what we call the F emeriti
z-- which is basically the orbits the
positions and times of all the objects
actually in the system and then you can
show the final image okay okay no more
final image okay so because we are
looking forward to those final images we
wanted to let you know where and when to
look for them we anticipate the data on
the ground and on the web around 8
o'clock Pacific 11:00 Eastern tonight
just go to go dot nasa.gov slash Cassini
raw again that's go dot nasa.gov slash
Cassini raw and a big thank you to Mike
and thank you to all of all of you
joining us here in the house and online
we hope that you'll be
back with us as we broadcast live from
Mission Control here at JPL as the final
data are received from the spacecraft
the epic end of Cassini's grand finale
get your coffee we're going live at 4
a.m. Pacific 7:00 a.m. Eastern 11
o'clock UTC so Europe gets a break you
can watch on NASA TV or nasa.gov slash
live thank you so much for being here
today and we'll see you online
yeah
