
Pilot aims to fly super glider to the edge of space - curtis
http://www.cnn.com/2015/07/21/travel/oshkosh-airshow-perlan-super-glider/index.html
======
falcolas
I just watched the latest Mythbusters, where Adam went up in a U-2 spy
aircraft to 70k feet. The amount of preparation which went into the pressure
suits, pilot preparation, and other considerations was amazing.

How much of this technology will be available to these pilots, I wonder. At
normal aircraft cruising altitudes, in the event of a cabin depressurization,
you have less than 10 seconds before your judgement is impaired to the point
of being useless (time of useful consciousness [1]). Will the parachute be
their first line of defense against this, or their last? How about the threat
of being above the Armstrong limit [2]?

Lots of questions I would love to see answered.

[1]
[https://en.wikipedia.org/wiki/Time_of_useful_consciousness](https://en.wikipedia.org/wiki/Time_of_useful_consciousness)
[2]
[https://en.wikipedia.org/wiki/Armstrong_limit](https://en.wikipedia.org/wiki/Armstrong_limit)

~~~
teleclimber
In Perlan I, back in the Enevoldson/Fossett days they used pressure suits. See
pics in this article:

[http://www.flightglobal.com/news/articles/analysis-aiming-
fo...](http://www.flightglobal.com/news/articles/analysis-aiming-for-90000ft-
with-perlan-2-glider-414257/)

~~~
curtis
If you run into the registration wall for this article you can sidestep it by
doing a Google search for "ANALYSIS: Aiming for 90,000ft with Perlan 2
glider". This article is vastly better than the one I submitted from CNN.

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mtm
There's a great podcast where Einar Enevoldson talks about the Perlan Project:
[http://www.stitcher.com/podcast/airplane-geeks-podcast-
podca...](http://www.stitcher.com/podcast/airplane-geeks-podcast-podcast-
feed/e/airplanegeeks-357-einar-enevoldson-and-the-perlan-project-39572525)

He goes into some detail about how they have to design around the low Reynolds
numbers at that altitude and other esoterica, very interesting.

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gilgoomesh
Very impressive.

But I wish journalists would avoid terms like "edge of space" unless the
journey actually goes anywhere near the Kármán line. This particular journey
will go a mere 30% of the way to space.

~~~
shasta
The Kármán line isn't the "edge of space" either.

------
aerocapture
The Perlan Project website:
[http://www.perlanproject.org/](http://www.perlanproject.org/).

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zw123456
I have seen a ton of info on the net about non-rocket launch systems (e.g.
balloons and planes, [http://www.space.com/28504-darpa-satellite-launching-
jet-ala...](http://www.space.com/28504-darpa-satellite-launching-jet-alasa-
xs-1.html)) but I have never seen anyone explore a glider, of course the
payload would be limited to a micro- satellite. But with a glider, you don't
have the fuel payload and it seems like the launch could be more controlled
than a balloon. If they pull this off I wonder if there is a commercial
application there ?

~~~
azernik
You do still have a fuel requirement - a satellite needs to get up to orbital
velocity of around 7km/s, which is where most of the fuel in a launch system
goes.

[https://what-if.xkcd.com/58/](https://what-if.xkcd.com/58/)

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astazangasta
Anyone with a handy explanation of how you can glide on air so thin?

~~~
johngalt
Thinner air produces less drag. You can travel faster over air that is less
dense. Meaning the total volume of air flowing over the wing still remains
high enough to provide lift. A 400mph glider would get torn apart at normal
pressures, but at 90k it won't.

Relatively 'normal' gliders have been over Mt. Everest.

~~~
mannykannot
As the density of the air falls with altitude, an airplane's stalling speed
(true, not indicated) rises. Conversely, as the temperature falls, so does the
speed of sound. The convergence of these two values puts a practical upper
limit on the altitude of a subsonic airplane. The glider's edge here is in
having a low stalling speed.

[https://en.wikipedia.org/wiki/Coffin_corner_(aerodynamics)](https://en.wikipedia.org/wiki/Coffin_corner_\(aerodynamics\))

~~~
protomyth
That's probably why their website says "PHASE 3 This phase will set a goal of
exploring the stratosphere up to 100,000 feet. Flight speeds will increase to
the point where the glider will need new transonic wings. Flight operations
will be extended to exploring the Polar Vortex in the northern hemisphere."

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curtis
I wonder if you could use glider technology to host a telescope, similar (but
much, much smaller) to the Stratospheric Observatory for Infrared Astronomy
[1], which is mounted in a 747.

[1]
[https://en.wikipedia.org/wiki/Stratospheric_Observatory_for_...](https://en.wikipedia.org/wiki/Stratospheric_Observatory_for_Infrared_Astronomy)

~~~
watersb
SOFIA is (of course) an infrared instrument. For infrared, water vapor really
messes up the light, like trying to see through fog. So getting above almost
all of the water made up for the complexity added by a moving platform.

If a glider could get up there at a pre-determined time, and fly a stable
course, that would be really cool. If the glider can't be relied upon to be
on-station at a certain time, perhaps because of sensitivity to weather on the
way up, then it would be hard to plan your science.

Someone should try it!

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skykooler
So the glider tech in Seveneves is possible then? I thought it seemed
implausible that a glider could fly so high.

~~~
reubenswartz
That was my first thought, as well. Would be awesome to see it work, even
though the really cool stuff in that scene is a long way off. ;-)

