Pilot aims to fly super glider to the edge of space | Hacker News Reader

Pilot aims to fly super glider to the edge of space

cnn.com

47 pointscurtis18 comments

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 [2] https://en.wikipedia.org/wiki/Armstrong_limit

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...

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.

Russian space suits are not so expensive.

There's a great podcast where Einar Enevoldson talks about the Perlan Project: http://www.stitcher.com/podcast/airplane-geeks-podcast-podca...

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

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.

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

The Perlan Project website: http://www.perlanproject.org/.

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...) 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 ?

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/

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

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.

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)

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."

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_...

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!

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

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. ;-)

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