# The Pentagon is tracking a Chinese spy balloon **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [February 3, 2023, 1:32am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228 "2023-02-03T01:32:54Z")\ **Posts on this page:** 20\ **Page:** 24
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [February 8, 2023, 3:06am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/462 "2023-02-08T03:06:02Z")
> [@DesertDog](#): > > > [@Al128](#): > > > > interesting tidbits … propellers and rudder … > > Makes it sound closer to a blimp than a balloon, despite its shape. So, do I win a cookie for saying it was maneuverable? ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [February 8, 2023, 3:20am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/463 "2023-02-08T03:20:01Z")
Perhaps somewhat but I remember watching one of the mini-blimps they use at football games struggle against the wind trying to fly eastward to it’s next assignment. It spent about fifteen minutes more or less over the house going more up and down than forward as it bucked a gusty headwind. I can’t imagine solar-powered motors doing much more than a suggestion of where it wants to go. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [February 8, 2023, 3:56am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/464 "2023-02-08T03:56:12Z")
Up in the seriously high altitude regime, say 60K feet and above, winds above about 10 knots are rather rare. So blimp-like performance might be quite valuable. Though I’m still baffled about the idea of propulsion _and_ a nearly-spherical shape. Those are two things that go together so badly that I have a hard time imagining it would not be better to reshape the balloon before adding propulsion. ---
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [February 8, 2023, 4:12am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/465 "2023-02-08T04:12:23Z")
> [@LSLGuy](#): > > I’m still baffled about the idea of propulsion _and_ a nearly-spherical shape. Those are two things that go together so badly that I have a hard time imagining it would not be better to reshape the balloon before adding propulsion. At vessel speeds under ~20 knots air resistance is negligible, so shape doesn’t matter much. ---
**Author:** ![excavating\_for\_a\_mind](https://avatars.discourse-cdn.com/v4/letter/e/e8c25b/32.png) [@excavating\_for\_a\_mind](https://boards.straightdope.com/u/excavating_for_a_mind)\ **Post date:** [February 8, 2023, 4:39am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/466 "2023-02-08T04:39:40Z")
> [@LSLGuy](#): > > Though I’m still baffled about the idea of propulsion _and_ a nearly-spherical shape. Those are two things that go together so badly that I have a hard time imagining it would not be better to reshape the balloon before adding propulsion. At 60000+ feet, the air is so thin that propeller propulsion would be negligible. ---
**Author:** ![smithsb](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smithsb/32/12107_2.png) [@smithsb](https://boards.straightdope.com/u/smithsb)\ **Post date:** [February 8, 2023, 7:41am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/467 "2023-02-08T07:41:43Z")
From when the western allies were launching 1000s of surveillance balloons over the Soviet Union and other parties. Russian aircraft and weapon development; fascinating and just a small part of the Cold War. > **[The Soviets Built Bespoke Balloon-Killer Planes During The Cold War](https://www.thedrive.com/the-war-zone/the-soviets-built-bespoke-balloon-killer-planes-during-the-cold-war)** > > With high-altitude surveillance balloons back in vogue, it’s worth taking a look at how the Soviets considered fighting these tricky targets. One of the US balloon projects with links to others: [General Mills manufactured surveillance balloons???] > **[Project Genetrix](https://en.wikipedia.org/wiki/Project_Genetrix)** > > Pages for logged out editors learn more > > Project Genetrix, also known as WS-119L, was a United States Air Force program designed to launch General Mills manufactured surveillance balloons over China, Eastern Europe, and the Soviet Union to take aerial photographs and collect intelligence. The Genetrix balloons reached altitudes of 50,000–100,000 feet (15–30 km), well above any contemporary fighter plane. > In 1955, a number of AN/DMQ-1 gondolas were launched from Lowry Air Force Base in C... ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [February 8, 2023, 9:04am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/468 "2023-02-08T09:04:05Z")
> [@excavating\_for\_a\_mind](#): > > At 60000+ feet, the air is so thin that propeller propulsion would be negligible. Quite. The propellers and rudder might only be there to orient the solar panels, like the tail on a windmill. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [February 8, 2023, 9:06am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/469 "2023-02-08T09:06:25Z")
> [@](#): > > The Soviets recovered many of these balloons and their temperature-resistant and radiation-hardened film[[8]](https://en.wikipedia.org/wiki/Project_Genetrix#cite_note-damn-8)[[9]](https://en.wikipedia.org/wiki/Project_Genetrix#cite_note-9)[[10]](https://en.wikipedia.org/wiki/Project_Genetrix#cite_note-10) would later be used in the [Luna 3](https://en.wikipedia.org/wiki/Luna_3) probe to capture the first images of the far side of the [Moon](https://en.wikipedia.org/wiki/Moon). Waste not, want not, eh? ---
**Author:** ![Al128](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/al128/32/16541_2.png) [@Al128](https://boards.straightdope.com/u/Al128)\ **Post date:** [February 8, 2023, 11:02am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/470 "2023-02-08T11:02:35Z")
> [@carnivorousplant](#): > > So, do I win a cookie for saying it was maneuverable? a cookie - no, … a meat-patty - yes > [@LSLGuy](#): > > Though I’m still baffled about the idea of propulsion _and_ a nearly-spherical shape. Those are two things that go together so badly that I have a hard time imagining it would not be better to reshape the balloon before adding propulsion. bear in mind that the air is way thinner up there, and hence air-resistance and drag are way lower, too… of course the same principle applies to the propeller, which does propell in very thin air - maybe a special (thin air optimized?) design of a propeller, - one that would be too “aggressive” for sea-level air, but works (relatively) better in the 50k-100k altitude?? ---
**Author:** ![scudsucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scudsucker/32/14101_2.png) [@scudsucker](https://boards.straightdope.com/u/scudsucker)\ **Post date:** [February 8, 2023, 11:11am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/471 "2023-02-08T11:11:37Z")
> [@not\_what\_you\_d\_expect](#): > > Bread boxes must be coming back in style This is wildly off topic, but I have a [breadbox](https://pedersenlennard.co.za/products/breadbin?variant=36627739784), cleverly designed to hold a recipe book as well ---
**Author:** ![Love\_Rhombus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/love_rhombus/32/10694_2.png) [@Love\_Rhombus](https://boards.straightdope.com/u/Love_Rhombus)\ **Post date:** [February 8, 2023, 11:41am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/472 "2023-02-08T11:41:30Z")
I read that they took the debris to the FBI in Quantico. Why not a military base? Surely that would be closer? ---
**Author:** ![Cervaise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cervaise/32/16693_2.png) [@Cervaise](https://boards.straightdope.com/u/Cervaise)\ **Post date:** [February 8, 2023, 11:59am UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/473 "2023-02-08T11:59:09Z")
For security, maybe yeah. But I’m skeptical the average military base has a modern forensics laboratory where the material can be examined and tested. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [February 8, 2023, 12:05pm UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/474 "2023-02-08T12:05:24Z")
> [@Cervaise](#): > > I’m skeptical the average military base has a modern forensics laboratory where the material can be examined and tested. If they seriously think it’s a “spy balloon,” then I would expect it would go to [NASIC](https://en.wikipedia.org/wiki/National_Air_and_Space_Intelligence_Center). (Which, BTW, is on the same base where my lab is located, and I collaborate with their lab on occasion. And that’s probably all I’m allowed to say about it. 🙂) ---
**Author:** ![Love\_Rhombus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/love_rhombus/32/10694_2.png) [@Love\_Rhombus](https://boards.straightdope.com/u/Love_Rhombus)\ **Post date:** [February 8, 2023, 12:08pm UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/475 "2023-02-08T12:08:42Z")
Yeesh, it seems like every day I learn there’s _another_ federal agency. Not discounting their work, just that I’m always amazed at the size of the government. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [February 8, 2023, 1:30pm UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/476 "2023-02-08T13:30:15Z")
Also, we don’t want to confuse where they took the debris _first_ and got it inside the cocoon of US Gov’t secrecy, from where the debris _ends up_ being analyzed in detail. Where the electronic hardware ends up, where the balloon material ends up, and where any data captured ends up are probably 3 different labs belonging to 3 different major government agencies. ---
**Author:** ![Dorjan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dorjan/32/12440_2.png) [@Dorjan](https://boards.straightdope.com/u/Dorjan)\ **Post date:** [February 8, 2023, 1:44pm UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/477 "2023-02-08T13:44:05Z")
> [@LSLGuy](#): > > Though I’m still baffled about the idea of propulsion _and_ a nearly-spherical shape. Those are two things that go together so badly that I have a hard time imagining it would not be better to reshape the balloon before adding propulsion This. Plus I’ve seen a high res photo and there was no evidence of rudders or propellers. I’m leaning towards an error in reporting or being BS’ed by whomever they interviewed. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [February 8, 2023, 1:45pm UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/478 "2023-02-08T13:45:15Z")
Is a sphere less area than a blimp shape for the same volume? ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [February 8, 2023, 1:47pm UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/479 "2023-02-08T13:47:34Z")
> [@Dorjan](#): > > This. Plus I’ve seen a high res photo and there was no evidence of rudders or propellers. I’m leaning towards an error in reporting or being BS’ed by whomever they interviewed. The only pictures I’ve seen are shredded fabric and parts of a truss. ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [February 8, 2023, 1:49pm UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/480 "2023-02-08T13:49:28Z")
Not to take the thread off topic but I really don’t understand why there couldn’t be a big CIA that encompasses all the different agencies - NSA, DIA, NRO, etc. all folded into one. I also wonder if, a U-2 plane, at the right altitude, could have used a drag-net to capture the balloon, but this might have sent the plane into a stall, to put it mildly. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [February 8, 2023, 2:25pm UTC](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228/481 "2023-02-08T14:25:07Z")
> [@smithsb](#): > > At that altitude, 60k ft., there is almost no difference in the outside pressure and inside the gas bag. No pop. For a high-altitude balloon launched from ground, the pressure differential at altitude is likely to be more than the differential at ground level. There appear to be two kinds of high-altitude balloon designs: - One uses an elastic gas envelope. At ground level, it’s approximately round (see pictures in **[this article](https://stac.berkeley.edu/project/balloon)**), and the material (latex rubber or something with similar mechanical properties) is under approximately uniform tension all around it. \*Another uses whisper-thin plastic material, with a mesh of cables or straps across the top of it carrying the load of the cargo below (pictures in **[this article](https://www.space.com/41791-giant-nasa-balloon-big-60-breaks-record.html)**). At ground level, it’s a tear-drop shape: the main bulk of the helium is at the top of the envelope, and since the material is not designed to stretch elastically, there’s extra space left inside the envelope for the helium to expand as the balloon rises. For the elastic gas envelope, when ambient pressure drop as the balloon rises, the envelope increases in size, stretching the elastic material. With greater tension in the material, the difference between interior and exterior pressure will be greater than it was at ground level. For the whisper-thin plastic gas envelope, the shape changes from a tear drop (at ground level) to something more spherical at high altitude as the helium expands and fills the envelope more completely. As the width of the envelope increases, the straps connecting the cargo to the envelope all change their angle, resulting in greater tension in those straps and more lateral squeezing force being exerted on the envelope. This will result in greater tension on the envelope material than is seen at ground level (and so a greater pressure differential than at ground level) - but since the material is so thin, it surely can’t take on _much_ tension. I suspect that when you pierce an elastic gas envelope at a single point, you’re likely to create a tear that propagates across the entire envelope, same as what you get when you pop a latex party balloon. For the whisper-thin plastic gas envelope, a catastrophic tear propagating from a single point seems less likely, since there’s less tension. In the case of the Chinese spy balloon, whatever it was made of, the shock wave and shrapnel from the missile’s **[continuous-rod warhead](https://en.wikipedia.org/wiki/Continuous-rod_warhead)** appear to have shredded the envelope rather nicely. [Previous page](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228.md?page=23) [Next page](https://boards.straightdope.com/t/the-pentagon-is-tracking-a-chinese-spy-balloon/979228.md?page=25)