
Chaff Cloud That Lit Up Radars as It Drifted Across Midwest Remains a Mystery - molecule
http://www.thedrive.com/the-war-zone/25438/huge-chaff-cloud-that-lit-up-radars-as-it-drifted-across-the-midwest-remains-a-mystery
======
aurizon
Chaff has always been a short term phenomenon - it settles, so how do you make
it neutrally dense or even lighter than air so it will not settle. The key is
related to the aluminum coated Mylar balloons - make them as light as air,
Helium diffuses out quickly but if you use hydrogen you can create a chaff
machine that uses two sheets of plastic, one coated with very thin aluminum.
trap helium or hydrogen between them, then laminate and separate them into
tiny tubes with neutral density so the residence time in air is quite a few
hours with Hydrogen, lots less with helium. You can make it in advance, but
popped popcorn fills a plane quickly, but unpopped corn allows you to mobilize
more chaff in the plane. This would be a good method to fox radar guided
missiles, or radar satellite surveys or launches. These short straws of Mylar
would have the needed aerial residence time and could even be made to rise,
loiter and then fall with the right choice of gasses (mixed hydrogen and
helium allows a rise, followed by a fall as the helium diffuses out) - saves
helium as well

~~~
aurizon
both sheets need to be metallized to reduce diffusion across the film.

------
brootstrap
Interesting. I was looking at radar with my co-worker yesterday, we saw these
scans and were like WTF is going on? Chaff from a C-130 huh? They do some
interesting stuff with those planes. I worked on a project where we flew C-130
thru clouds, took pictures of the clouds and did data analysis etc.

Spent an entire summer analyzing pictures of ice crystals like this [1] in
MATLAB. Fun times...

[1] [https://www.eol.ucar.edu/instruments/two-dimensional-
optical...](https://www.eol.ucar.edu/instruments/two-dimensional-optical-
array-cloud-probe)

~~~
debt
Might've been "smart" chaff to achieve this same thing.

Kinda like that fake tech they used in the movie Twister to map tornados.

------
zrail
They issued an update today with quotes from the West Virginia Air National
Guard:

[http://www.thedrive.com/the-war-zone/25451/a-west-
virginia-a...](http://www.thedrive.com/the-war-zone/25451/a-west-virginia-air-
guard-c-130h-was-responsible-for-massive-chaff-cloud-over-midwest)

------
mannykannot
I thought of migrating birds, as they sometimes show up on radar, but there
does not appear to be anything here[1] corresponding to this event.

[1] [http://birdcast.info/live-migration-maps/](http://birdcast.info/live-
migration-maps/)

Update: I got the date wrong, this would have been Dec 10... Data is missing
from 10:40 to 16:10 CT, and the spatial resolution is not high, but the map is
showing medium rates of migration in that area at the later time.

------
marktangotango
Seems like the same people who search for meteorites could get a general
location for where this went off radar and go walk around. Other than actual
chaff, my mind goes to possible “black projects” when reading things like
this. I can’t think of any possible applications though.

~~~
mnw21cam
It looks like once this stuff has dispersed into the air, it is very fine and
sparse, so there probably won't be much to see on the ground. Must do wonders
for the local wildlife though.

~~~
dsfyu404ed
Unless it's laced with some exotic heavy metal it's probably better for the
environment than most plastics.

~~~
mnw21cam
If it's thin aluminium foil, then it'll probably decompose fairly quickly. I'm
more concerned about what will try eating it before it does so.

------
mcguire
" _The Red Hills MOA is relatively large, including areas of both Illinois and
Indiana. We don 't know if the MOA was active at the time the plume appeared
on radar, but it might help explain the incident._"

The military releases "notices to airmen" (NOTAMs?) indicating when a MOA is
in use, no?

------
mothsonasloth
I wonder if they will be able to put AI into missiles to detect Infrared
decoys (flares, IR laser) or radar countermeasures (chaff, jamming).

Military countermeasures are really cool, if you can get past the whole moral
dilemmas in working with technology like that.

~~~
jhayward
> _I wonder if they will be able to put AI into missiles_

Missiles arguably already have AI. It is a source of mild frustration for
control systems engineers to note AI researchers "discovering" techniques and
algorithms that are mathematically identical, or very similar to, things that
have been known and used in control systems for years, decades even.

~~~
sterlind
That's the downside of working on classified tech, right? You get huge budgets
and work a decade ahead of civilian gear, but you're doomed to see civs
reinvent your stuff and take all the credit.

For instance, the NSA had public key crypto long before RSA was discovered.

~~~
jhayward
Yes, it happens in secret vs open but I'm talking about all open stuff. It
just isn't sexy when control systems engineers do it.

------
FlyMoreRockets
You do realize we're in the middle of a fairly intense meteor storm, where
lots of sand sized particles are turned to plasma when they hit the
atmosphere, right?

It was even today's Google Doodle.

------
avoutthere
"chaff was released by a military C130 [sic] northwest of Evansville."

Not exactly a mystery.

~~~
edkennedy
Uncorroborated seemingly random claim on twitter as stated in the article.

------
time-domain0
If the chaff had maximum surface area-to-weight ratio approaching spiders
ballooning, <2.5 um dust particles and dandelion seeds, and there were enough
thermals upwelling air in the area, it's entirely possible for chaff to
persist as long as there is an average slight updraft gradient to periodically
relift material.

Granted, it's of limited military value unless it were dumped in large
quantities (such as an/several E- prefixed US mil aircraft flying air defense
suppression/Wild Weasel) and such upwelling wind conditions were present. It's
usually intended to create false echoes to misdirect a missile or break a
radar lock in real-time with a starting velocity similar to the original
aircraft, and then it has no purpose once it separates far from the launching
aircraft.

~~~
dylan604
Doesn’t the chaff need to be of certain lengths to match the frequencies of
the incoming radar. I thought I read something about that in one of my
previous wake cycles

~~~
madengr
Yes, peak scattering will occur at 1/2 wavelength, and multiples of that.

------
mnw21cam
"By clicking continue below and using our sites or applications, you agree
that we and our third party advertisers can:" break EU law and screw us over.

No thanks.

[https://outline.com/36cJVa](https://outline.com/36cJVa)

~~~
everyone
It seems I need to use Outline to read the majority of articles linked here.
Outline is a great site!

~~~
psychometry
Does it work on paywalled pages like WSJ?

