5 ms·

Pilot aims to fly super glider to the edge of space

47 points by curtis 11y ago

aerocapture 11y ago
The Perlan Project website: http://www.perlanproject.org/ http://www.perlanproject.org/.
astazangasta 11y ago
Anyone with a handy explanation of how you can glide on air so thin?
- johngalt 11y ago
  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 11y ago
    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 11y ago
      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."
gilgoomesh 11y ago
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 11y ago
  The Kármán line isn't the "edge of space" either.
falcolas 11y ago
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 11y ago
  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-for-90000ft-with-perlan-2-glider-414257/ http://www.flightglobal.com/news/articles/analysis-aiming-fo...
  - curtis 11y ago
    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.
- jkot 11y ago
  Russian space suits are not so expensive.
mtm 11y ago
There's a great podcast where Einar Enevoldson talks about the Perlan Project: http://www.stitcher.com/podcast/airplane-geeks-podcast-podcast-feed/e/airplanegeeks-357-einar-enevoldson-and-the-perlan-project-39572525 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.
zw123456 11y ago
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-alasa-xs-1.html 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 ?
- deleted 11y ago
  [deleted]
- azernik 11y ago
  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/
skykooler 11y ago
So the glider tech in Seveneves is possible then? I thought it seemed implausible that a glider could fly so high.
- reubenswartz 11y ago
  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. ;-)
curtis 11y ago
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_Infrared_Astronomy https://en.wikipedia.org/wiki/Stratospheric_Observatory_for_...
- watersb 11y ago
  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!

47 points by curtis 11y ago

aerocapture 11y ago

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

astazangasta 11y ago

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

johngalt 11y ago
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 11y ago
  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 11y ago
    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."

gilgoomesh 11y ago

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 11y ago
The Kármán line isn't the "edge of space" either.

falcolas 11y ago

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 11y ago
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-for-90000ft-with-perlan-2-glider-414257/ http://www.flightglobal.com/news/articles/analysis-aiming-fo...
- curtis 11y ago
  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.
jkot 11y ago
Russian space suits are not so expensive.

mtm 11y ago

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

zw123456 11y ago

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-alasa-xs-1.html 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 ?

deleted 11y ago
[deleted]
azernik 11y ago
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/

skykooler 11y ago

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

reubenswartz 11y ago
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. ;-)

curtis 11y ago

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_Infrared_Astronomy https://en.wikipedia.org/wiki/Stratospheric_Observatory_for_...

watersb 11y ago
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!