
The Jet With a 17-Ton Telescope That NASA Uses as a Flying Observatory - nealabq
http://www.wired.com/2014/07/nasa-sofia-flying-observatory/
======
Serow225
Very cool, I worked with one of the engineers who did the stress & airflow
analysis for cutting that big hole in the plane, it was really interesting to
hear his stories! And yes, as goodcanadian stated elsewhere in this thread,
there are airflow management modifications in front of and behind the door to
make this all possible.

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netcraft
I wonder if the plane flies during the day or night? I would assume that for a
given mission its one or the other, which makes me also wonder how fast or
slow it flies. Even though it is looking in the infrared - wouldn't the
daylight still affect it?

~~~
goodcanadian
We only fly at night. Well, technically speaking, we can observe with the sun
up, but the guider cameras are optical which makes it nearly impossible to
track any targets when the sky is bright. Moreover, we have to stay well away
from the sun as the telescope would focus the sunlight with enough intensity
to destroy itself. So, yeah, we only fly at night.

Airspeed is roughly mach 0.85.

~~~
jessedhillon
Is there some way that civilians admirers can ride SOFIA and get to
participate in some of those activities set aside for grade schoolers? I would
certainly be as excited as any 6th grader to have that chance!

~~~
goodcanadian
Grade schoolers don't fly on SOFIA. The Airborne Astronomy Ambassadors program
is for grade school teachers and other educators. I can't think of any obvious
way for the general public to fly on SOFIA. If you are a professional
astronomer, apply for time, and you may be invited to fly. If you are an
educator, apply to the Airborne Astronomy Ambassador program.

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dylanrw
During one of my many Lyft rides I learned the driver was also one of several
managers on this project. We had an interesting chat about it, and it left me
wishing that the people involved in this sort of work were paid substantially
more.

~~~
john_b
Agreed, unfortunately meaningful projects such as this are not a high priority
for the US electorate (and thus the US Congress) [1]. My hope is that growing
interest by college students in STEM subjects [2] will ultimately lead to an
increased understanding of the importance of these projects in the long term.

[1]
[http://en.wikipedia.org/wiki/Budget_of_NASA](http://en.wikipedia.org/wiki/Budget_of_NASA)

[2]
[https://www.stemconnector.org/sites/default/files/store/STEM...](https://www.stemconnector.org/sites/default/files/store/STEM-
Students-STEM-Jobs-Executive-Summary.pdf)

~~~
rbanffy
One could always ask for support saying a given experiment could prove the,
say, biblical flood or somethimg equally silly. If someone believes that all
animals on Earth descend from the living cargo of a wooden ship, it should be
possible to convince them of _anything_.

Hacking a right-wing nutty congresscritter is an intriguing concept.

~~~
chenelson
And, I guess, Bill Maher is a right-wing nutty? He believes Mars and Moon
missions would be a great waste of money.

The Bible isn't holding us back....it's our lack of imagination and lazy jokes
and the conflation of capital and fiat currency.

~~~
rbanffy
> He believes Mars and Moon missions would be a great waste of money.

If they fail to inspire people to continue exploring, yes. I would prefer Moon
missions because they'd be cheaper and, as far as inspiration goes, they'd
achieve the same results. How many brilliant people have chosen to dedicate
their talents to building web technologies because space is no longer cool?

Also, being able to build self sustaining off world colonies may prove handy
if we end up unable to stop climate change...

~~~
chenelson
I think if something is inspirational, it must be realizable; thus, unless
we're talking about mining the moon and requiring human's for labor, we're
going to miss the point.

Climate change on Earth is a constant, and if time is x, human existince is a
speed bump.

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nawitus
How long are the exposures? One would think that due to vibration etc. the
exposures need to be extremely short, but long exposures are beneficial in
astrophotography.

EDIT: Wikipedia answers the vibration issues:
[http://en.wikipedia.org/wiki/Stratospheric_Observatory_for_I...](http://en.wikipedia.org/wiki/Stratospheric_Observatory_for_Infrared_Astronomy#The_telescope)

~~~
goodcanadian
There have been a couple of good answers with regard to exposure time. With
regard to vibration, the telescope is floated on an oil bearing and gyro
stabilized. It is well isolated from aircraft vibrations.

~~~
rbanffy
I imagine some interesting ideas of cabin noise management could be derived
from research around this...

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ddrmaxgt37
My favorite 747! It's the 747SP. I love how short and fat it looks.

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aunty_helen
Here is one of the runs they did last year:
[http://flightaware.com/live/flight/NASA747/history/20130717/...](http://flightaware.com/live/flight/NASA747/history/20130717/0612Z/NZCH/NZCH)

The arches are when they are doing their observations.

Edit: For some reason the map is centering over the Atlantic when I open the
link, the flight path is actually from New Zealand if you can't see it to
start with.

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valarauca1
I wonder how it'll compare to _eventually to be launched_ James Webb
Telescope.

~~~
privong
At wavelengths which they both observe (~1–28.5 microns; SOFIA goes out to
longer wavelengths than JWST), JWST will be far superior in terms of both
sensitivity and resolution. For one, the mirror on SOFIA is less than half the
diameter of that on JWST ([0],[1], so the resolution is less than half as good
and the collecting area is down by more than a factor of four). Even though
SOFIA flies above a lot of the infrared-absorbing atmosphere, it still suffers
from some absorption. Additionally, the aircraft and the remaining atmosphere
emit in the infrared, so the background levels for SOFIA are much higher.

That being said, SOFIA operates at far-infrared wavelengths as well, which
JWST will not support. There are satellite missions being propose which would
work in the far-infrared; none have been fully approved yet (to my knowledge),
but any of them would surpass SOFIA in most metrics (except perhaps spectral
resolution).

[0]
[http://www.sofia.usra.edu/Science/telescope/index.html](http://www.sofia.usra.edu/Science/telescope/index.html)

[1]
[http://jwst.nasa.gov/faq_scientists.html#whatis](http://jwst.nasa.gov/faq_scientists.html#whatis)

~~~
goodcanadian
Indeed, there are a couple of key things to note:

1) JWST has not been launched, yet.

2) SOFIA's wavelength coverage is different that JWST's or anything else that
is in the pipeline.

So, really, they are complimentary observatories.

~~~
privong
> 2) SOFIA's wavelength coverage is different that JWST's or anything else
> that is in the pipeline.

Depending on what you mean by "pipeline", that isn't quite true. Work is being
done on several far-inrared missions, such as SPICA[0]. I'd consider SPICA to
be in "in the pipeline" and it will cover much (if not all) of the far-
infrared that SOFIA does. So I wouldn't call JWST and SOFIA complementary;
rather, SOFIA is a precursor observatory and a potential technology
development platform (for things like SPICA; not so much for JWST, since the
JWST instruments are already being built).

[0]
[https://en.wikipedia.org/wiki/SPICA_telescope](https://en.wikipedia.org/wiki/SPICA_telescope)

~~~
welterde
I wonder how much more expensive Herschel would have been, if ESA had gone
with an closed-cycle cooler instead of using a limited liquid Helium supply
directly.

~~~
privong
I'm not sure closed-cycle coolers can get as cold as evaporation of liquid
helium? Herschel was cooled to ~1.7 K [0] while MIRI will only be cooled to 7K
[1]. Also, with regard to reliability, evaporation of liquid helium is a
pretty foolproof design, while closed-cycle systems can potentially break and
end a mission early.

[0]
[https://en.wikipedia.org/wiki/Herschel_Space_Observatory#Ins...](https://en.wikipedia.org/wiki/Herschel_Space_Observatory#Instrumentation)

[1] [http://jwst.nasa.gov/miri.html](http://jwst.nasa.gov/miri.html)

~~~
welterde
Are the individual instruments cooled to that temperature though? Because if
they are not, then the difference doesn't matter.

Had a look at the SPIRE manual [0][1] and it seems that Herschel does include
an Helium cooler to cool SPIRE and PACS to 300mK.

On the other hand a closed-cycle system can also extend the mission, since you
won't run out of cooling at a fixed point in time.

[0]
[http://herschel.esac.esa.int/Docs/SPIRE/html/spire_handbook....](http://herschel.esac.esa.int/Docs/SPIRE/html/spire_handbook.html)
[1]
[http://herschel.esac.esa.int/Docs/Herschel/html/ch02.html](http://herschel.esac.esa.int/Docs/Herschel/html/ch02.html)

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ra
There's a fantastic BBC Horizon documentary called, "Seeing Stars" which
includes, among other things, a SOFIA mission:
[http://www.dailymotion.com/video/x1kacli_bbc-
horizon-2011-se...](http://www.dailymotion.com/video/x1kacli_bbc-
horizon-2011-seeing-stars-pdtv-xvid_tech)

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rosser
Opening that door must do abysmal things to the plane's drag coefficient.

~~~
goodcanadian
As I understand it, opening the door has negligible effect on the performance
of the aircraft. The shape of the fuselage is modified to send airflow past
the aperture.

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qwerty_asdf

      The telescope on board is 10 times as sensitive 
      and has triple the resolution of NASA’s Kuiper 
      Airborne Observatory, originally launched in 
      1975 on a converted C-141 military cargo plane, 
      and decommissioned in 1995. That telescope was 
      the first to spot the rings around Uranus.
    

"...the rings around Uranus."

