The US Military is Making Balloons That Hover at the Edge of Space, Indefinitely (technologyreview.com)

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.

Comments

Project Loon

[Anonymous Coward]

This sounds an awful lot like Google's Project Loon just for another purpose.

because its flat

[Anonymous Coward]

because its flat

Seveneves by Neal Stephenson

[Allasard]

**SPOILER**

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.

Re: Seveneves by Neal Stephenson

[Anonymous Coward]

The balloons could calculate that on the fly (ha ha) but they are too far from each other for a signal to reach

Re:Seveneves by Neal Stephenson

[Anonymous Coward]

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 of just over 500 mph. An amazing accomplishment!!

Re: Your tax dollars pay for it

[Anonymous Coward]

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

Re:Your tax dollars pay for it

[MAXOMENOS]

you get absolutely nothing for it.

Better weather predictions from easier-to-maintain-than-satellite sensors sounds like something I get for it.

What is Winter Sunlight?

[Anonymous Coward]

For this reason, God sends them a powerful delusion(operation of wandering)(planet) so that they will believe the lie.

Adjustment Energy?

[BrendaEM]

Where is the energy for the adjustments going to come from? Solar? Nuclear?

Re:Adjustment Energy?

[Anonymous Coward]

solar, as noted in the second sentence of the article

Definitely

[Anonymous Coward]

If they are going to make balloons indefinitely how many will they end up making? Enough to block the sun and control the weather?

nice while it lasted

[Anonymous Coward]

You do realize you anti-vaxxer, red-pilling flat-Earther Trumpanzees have trolled us right into the collapse of Civilization, right?

Re:nice while it lasted

[Highdude702]

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

Re:nice while it lasted

[Anonymous Coward]

If any Trumptards finally come to the realization that they've been had, they'll never have the guts or integrity to admit it. Trump is the political hill they'll die on. It's sports team identity fusion:

Identity Fusion - aka “Sports team” mode
A majority of the United States is confused by the behavior of ~34% of the rest of the country.

To grasp what has happened, you just have to realize that some political supporters have gone into “Sports Teams” mode. They have turned politics into an Identity Fusion issue.

Basically, they have stopped thinking about the representative government as a functional group of public servants. They are thinking about it as if it's their "team" and everything political has become "us versus them."

Some characteristics of a team fanatic
[ I'm using Trump Supporters as an example because it's currently the most obvious example, but it can apply to both sides to some degree. ]

Once you realize this is what's happening, the common attributes are there to see:

-- Wearing identifying clothing (hats, badges, colors, logos, slogans) in everyday life.

-- Loyalty regardless of performance or behavior of their "team."

-- Instant disrespect for any member of the opposing team based solely on team affiliation.

-- Hatred of any perceived disloyalty from fellow team fans.

-- Having rallies and parades even when there is no pending game with the primary goal to celebrate and reinforce being loyal.

-- At gatherings, fans chant slogans and/or sing.

-- Team players (not fans, but players) are 100% supported unless they leave the team. Then they are ostracized and demonized even though they are basically the same person.

This simple concept explains the logic-defying behavior we are constantly seeing in politics today.

a change "known as" doppler shift

[Anonymous Coward]

> "a change known as" doppler shift

Do they deliberately write these passages to imply their readers are idiots? People learn what doppler shift is probably around 7th or 8th grade (when you talk about snell's law and all that good stuff), but certainly by basic high school physics. By saying "a change known as doppler shift" rather than "this occurs because of doppler shift" or the like, the writer assumes every reader didn't make it past sixth grade. WTF?

Nice

[nospam007]

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.?

Re:Nice

[Thud457]

Obviously teh gubbament holds the secret to creating the NB gas used by the Sonora Aero club.

Re:Nice

[suutar]

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 :)

Re:Nice

[Anonymous Coward]

So they have a fabric that doesn't any helium through 'indefinitely'?

The ALTA balloon itself is made by Raven Aerostar, which also makes the Loon balloons.

There's a link to Raven Aerostar's page, looks like they have balloons capable of staying at extreme altitude longer than they can remain in a useful location relative to the ground. This DARPA tech proposes to put the burden of duration back on the balloons by improving stability.

All the rest is journalist hyperbole and designer enthusiasm.

Re:Nice

[Anonymous Coward]

Solar Stratolites are not really a new concept. Transparent Mylar, Reflective material on the inside at the bottom. I saw an interesting concept for a balloon rocket once, called the BelRoc that would incorporate pumps, a series of chambers and a Delave nozzle nozzle to allow it to achieve momentum, taking cold air in the front, expelling hot-air out the back.

I never saw convincing math that it could actually gain enough speed to put itself in to a real orbit, but the concept is interesting as a means of lift to build a semi-permanent SHIELD like helicarrier/sub-orbital launch complex. If you could get the lunch complex sub-orbital, and then have a series of BelRoc tugs that slow-hauled a second stage to the sub-orbital platform, you could launch small second stages from it from a much lower cost since the Solar power for the first stage is 'free'.

It would have to be done with economics of scale, and be a totally different method of 're-usability' than what SpaceX is going for, but interesting non-the-less

Re:Nice

[rtb61]

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 plasma, that plasma, although is in a high energy state, would be expanded to maximum volume with absolute minimum weight, way lighter than air, the energy demand would be high though.

Re:Your tax dollars pay for it

[suutar]

I wonder if this would be easier/cheaper than the 7k satellites SpaceX just got approval for?

Is it 99 red balloons?!?

[Anonymous Coward]

Floating in the Summer sky?!?!?

And so on

[Impy the Impiuos Imp]

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.

Re:And so on

[Anonymous Coward]

Help! Someones anus has broken loose!

Clowns

[Anonymous Coward]

Is this why I've noticed a lot of clowns holding strings that seemingly go indefinitely into the air?

Glad that's cleared up. It was creeping me out.

Re: Your tax dollars pay for it

[lgw]

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

[GameboyRMH]

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.

Imagine if a foreign power hacked a balloon

[Anonymous Coward]

"Those are my balloons.....HE STOLE MY BALLOONS!!! Why didn't somebody tell me he had one of those.....things!.......Bob, gun please. I'm gonna need a moment or two alone, boys."

Yes, but...

[nwaack]

...how close can they get to Uranus.

Two feet deep...

[Anonymous Coward]

... Toes, heels, ankles, calves, knees and everything!

Now I Get It!

[Anonymous Coward]

This is the Space Force we've been promised! A grandiose fleet of near-space balloons, that will keep the Neptunians out! And we'll use Uranus to pay for it!!

Weird sentence

[Anonymous Coward]

The US Military is Making Balloons That Hover at the Edge of Space, Indefinitely

So, the US military is making balloons indefinitely, and these balloons hover at the edge of space?