The US Military is Making Balloons That Hover at the Edge of Space, Indefinitely (technologyreview.com) 35
A sensor that can spot the wind direction from miles away will let DARPA's surveillance balloons hover at the very edge of space in one spot indefinitely. An anonymous reader writes: DARPA, the US military's research arm, is currently testing a wind sensor that could allow devices in its Adaptable Lighter-Than-Air (ALTA) balloon program to spot wind speed and direction from a great distance and then make the necessary adjustments to stay in one spot. DARPA has been working on ALTA for some time, but its existence was only revealed in September. "By flying higher we hope to take advantage of a larger range of winds," says ALTA project manager Alex Walan. ALTA will operate even higher than Loon at 75,000 to 90,000 feet (22,900 to 27,400 meters or 14 to 17 miles), where the winds are less predictable. That shouldn't be a problem if the balloon can see exactly where the favorable winds are.
The wind sensor, called Strat-OAWL (short for "stratospheric optical autocovariance wind lidar"), is a new version of one originally designed for NASA satellites. Made by Ball Aerospace, OAWL shines pulses of laser light into the air. A small fraction of the beam is reflected back, and the reflected laser light is gathered by a telescope. The wavelength of the reflected light is changed slightly depending on how fast the air it bounced back from is moving, a change known as doppler shift. By analyzing this shift, OAWL can determine the speed and direction of the wind. Unlike other wind sensors, OAWL looks in two directions at once, giving a better indication of wind speed and direction.
The wind sensor, called Strat-OAWL (short for "stratospheric optical autocovariance wind lidar"), is a new version of one originally designed for NASA satellites. Made by Ball Aerospace, OAWL shines pulses of laser light into the air. A small fraction of the beam is reflected back, and the reflected laser light is gathered by a telescope. The wavelength of the reflected light is changed slightly depending on how fast the air it bounced back from is moving, a change known as doppler shift. By analyzing this shift, OAWL can determine the speed and direction of the wind. Unlike other wind sensors, OAWL looks in two directions at once, giving a better indication of wind speed and direction.
Re: Your tax dollars pay for it (Score:2, Insightful)
I can no longer tell the difference between an unusual comment and lobtard drivel. Are people raising issues or just babbling? Funny thing about these balloons. They pop when they drop too low. Ideally they would make them a little stronger. Every time I hear trumps space force I picture that scene from starship troopers where the whole platoon got slaughtered in the first battle. Most people think that was a stupid movie but it was very insightful
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Every time I hear trumps space force I picture that scene from starship troopers where the whole platoon got slaughtered in the first battle.
Why imagine something other that Russia's space force? It's just the guys who do spy satellites moving from the Air Force to the Space Force (and whatever other payloads the AF launches).
Re:Your tax dollars pay for it (Score:5, Insightful)
you get absolutely nothing for it.
Better weather predictions from easier-to-maintain-than-satellite sensors sounds like something I get for it.
Re:Your tax dollars pay for it (Score:5, Interesting)
I wonder if this would be easier/cheaper than the 7k satellites SpaceX just got approval for?
Re: (Score:3)
A military sized to occupy a planet is a thing you get for your tax money, whether you personally see any value in it or not.
because its flat (Score:1)
because its flat
Re: (Score:1)
Pretty sure most of the flat earthers are foaming at the mouth calling Trump a nazi. But go ahead and group everyone you disagree with Into the same basket. It will make your life much better.. Lol
Seveneves by Neal Stephenson (Score:2)
That reminds me of the glider they used in Seveneves.
If I remember right, It was able to detect wind patterns at a distance and used that to glide up to the upper reaches of the atmosphere.
It would be interesting to build a craft that can increase it's height without propulsion.
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Interesting: There's a technique in flying radio control model gliders where the pilot can exploit the difference is velocity between two air bodies the gain energy. It's called "Dynamic Soaring". So it makes sense that airborne vehicles should be able to gain energy and so speed or altitude from air bodies moving in different directions and/or speeds.
https://www.youtube.com/watch?v=hFPJ6DUAY10
Here's the freaky thing: These guys get a radio controlled MODEL airplane with NO engine up to a world record speed
Adjustment Energy? (Score:2)
Nice (Score:3)
So they have a fabric that doesn't any helium through 'indefinitely'?
I'd like to see that.
Also, how do they heighten or lessen the buoyancy without ballast or additional gas to achieve that 'indefinitely' status.?
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Interesting question. What comes to my mind would be something like an automated hot air balloon; heat the air using solar-generated electricity to increase buoyancy, let it cool to decrease; possibly add/remove air from the bag using an electric pump. Not the fastest response time, but might be adequate for some purposes.
I'd be interested in seeing what methods they actually use, though :)
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How to adjust buoyancy at height without throwing stuff away, all too easy, compressed air by volume is much heavier than uncompressed air, so suck in air and fill a tank and the craft is now heavier.
The balloon only has value if it is big enough to take up rocket up to that height and obviating the need for a first stage. Theoretically if you had the energy, you can create a plasma balloon, where the highly expanded plasma, is contained within a balloon that is electromagnetically charged to contain the p
And so on (Score:3, Funny)
The US Military is Making Balloons That Hover at the Edge of Space, Indefinitely
Kind of like how neckbeards make balloons (fat bellies) that hover over the Empty Space in front of their genitalia, indefinitely.
Yes, but... (Score:2)