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TROY ASHER: SOFIA, itself, is just like any other 747.
It's a very nice airplane.
It's a pleasure to fly.
The hardest part about flying it is getting your body clock
in tune with flying all night.
The stars dictate how we fly.
SPEAKER 1: Tower at NASA 747 heavy, ready
for take-off, two-five.
SPEAKER 2: NASA 747 heavy, hold for runway 2-5 at [INAUDIBLE]..
SPEAKER 1: Hold sir, two-five, NASA 747 heavy.
ROBERT MEYER: SOFIA stands for Stratospheric Observatory
for Infrared Astronomy.
It's a flight observatory.
We don't know any other observatory
like this that's flying, in the world.
SPEAKER 2: NASA 747 heavy, clear for takeoff.
SPEAKER 1: Clear for takeoff.
ROBERT MEYER: It's an interesting blending
of aeronautics and astronomical science.
Part of the requirements for the design
were that the airplane fly just like it did originally.
The telescope itself is mounted in what
would be the very aft portion of the cabin of the 747.
And then there's a hole cut in the back of the airplane that
allows the telescope to look out and into the atmosphere.
EDWARD DUNHAM: The primary purpose
for putting a telescope in an airplane
is to fly high enough that the atmosphere is cold
and the water vapor has all frozen out.
Astronomers think water vapor is the problem.
It blocks out light that you would otherwise
want to be able to see.
Flying at an altitude of say, 43,000 feet,
the amount of water vapor that's left above us
is less than a half a percent of what
you'd see down on the ground.
SPEAKER 3: We just reached 40,000 feet.
SPEAKER 4: OK.
Thanks.
ERIC BECKLIN: The main goals of SOFIA
are to study the environment where stars are forming
and what is happening there, and also how planets form.
And then, trying to put this into the bigger
picture of how did life form?
To answer these questions, we work
with a variety of instruments.
We use imagers.
And we also have spectrometers that divide the light up.
And that allows us to see the details of what material
is there, the molecules, and the elements that are out in space.
SPEAKER 5: Still shooting?
SPEAKER 6: Yes.
[INAUDIBLE]
ROLF GUSTEN: The GREAT instrument works
like a classical radio.
We can tune the receiver to the emission
of far infrared wavelengths.
And that is a typical radiation that we also experience
when you get to a heater.
That's why we call it the heat radiation or the far infrared
radiation.
Most of the interstellar medium--
the gas, the dust, that is between stars
is radiating in the far infrared.
And this is the material that we study,
because that's sort of the source for the next generation
of stars to form.
All the important ingredients that we need for life,
are made in stellar processing.
Every piece of atom in our bodies
has been cycled several times in stars,
that's why we're so exciting.
SPEAKER 7: Delta, good evening.
Delta 1684 passing 31-3 for 3-0-0.
ALLEN: How is the positioning, Ted?
Its a little bit--
TED: It looks fine, Allen.
ALLEN: We're a little high.
That's all.
TED: Yeah.
When we've been three by three, like this, we can--
we can take full frames at this rate.
EDWARD DUNHAM: The instrument that we
built for SOFIA is called the high-speed Imaging
Photometer for Occultation.
SPEAKER 3: OK.
Allan, then, tell me when you're ready for the turn, please.
ALLEN: Turning now.
EDWARD DUNHAM: Any object you want to look at
always has to be to your left.
So you fly until you're done with that object,
and then you make a turn to your next object
and do another curvy loop.
And before you know it, you've flown 10 hours
and observed 8-15 different objects.
It does get to be quite intense.
SPEAKER 5: The final is 232 kilometers north
of the reference position and 40 seconds early.
SPEAKER 6: OK.
SPEAKER 5: And after this, it starts
blending with another star.
So they won't be getting any-- well, they'll get more data,
but it won't be of any good quality.
SPEAKER 6: Yeah, right.
SPEAKER 5: So I think we're done.
SPEAKER 6: Let's just do it.
SPEAKER 5: That's all we got.
SPEAKER 6: Let's just do it.
SPEAKER 5: OK.
EDWARD DUNHAM: The main purpose in observing
occultations is to work out the density of the atmosphere
of the planet.
SPEAKER 8: It looks like the URV is now open.
SPEAKER 3: Correct.
EDWARD DUNHAM: An occultation happens
when a planet in our solar system
happens to pass in front of a star.
You can also think of it as the star
casting a very faint shadow of the planet out into space.
The star light is refracted by the atmosphere of the planet.
The atmosphere is acting a little bit like a lens.
So our goal is to be at the right place at the right time
so that the shadow goes over us.
And obviously, with an airplane, you have a real leg up.
It's never cloudy.
And you can be anywhere you want to be.
Since Pluto's atmosphere was discovered in 1988
using this method, there have been
several ground-based occultation observed.
And it appears that Pluto's atmosphere
is getting more dense.
And we don't completely understand why.
This is the target star.
That's Pluto.
Pluto is moving this way.
[INAUDIBLE]
ALLEN: We're crossing the center line about now.
EDWARD DUNHAM: In the old days, our task was just
to get somewhere in the shadow.
The shadow is about as big as Australia.
TED: It's getting weaker.
ALLEN: Yes.
TED: Excellent.
EDWARD DUNHAM: But we kind of upped the ante, here.
We are trying to get to the center of the shadow now.
The center is just diagnostic of the overall global structure
of the atmosphere.
It's a difficult measurement to make,
but I'm hopeful that we'll be able to measure it with SOFIA.
TED: Are the files safe.
ALLEN: They're there.
We're done.
ERIC BECKLIN: Flying on SOFIA is a wonderful experience.
When you open the door and start making observations that you
cannot do any other way, and you see the data that no one has
ever seen the detail that you're looking at, it becomes very
exciting.
EDWARD DUNHAM: There are high points and low points
in every part of the operation.
There are times when things don't work
and you're completely frustrated.
But then there are times when you finally
figure out how to make it work.
And, generally speaking, on SOFIA things do work.
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