Re: Aug, 21, 1956; near Hamilton AFB, California (BB): AVCAT

Date: Wed, 14 Dec 2011 10:50:09 -0500 (GMT-05:00)
From: Jan Aldrich <>
Subject: Re: [Current Encounters] Aug, 21, 1956; near Hamilton AFB, California (BB): AVCAT

Ah, McDonald would have loved this one. Reference points. UFO against a contrail. Ah, but we don't know how high the contrail was. However, it is a limit problem. No exact measurements, but within limits things can be said about this one.



From: "Martin Shough" <>
To: <>
Date: Wed, 14 Dec 2011 18:08:17 -0000

within limits things can be said about this one<

It's a shame there isn't more information given, but we can say something:

The Joint Message form says the pilot thought the object "appeared to" go under the B-47 contrail. The phrase implies a matter of judgment, some possible uncertainty. Unfortunately there is no questionnaire or signed statement from the observers to help us gauge what this means.

Assuming the pilot's impression was correct, we could infer brackets on the object's altitude. It would be between the minimun typical height for formation of such a contrail and the maximum likely altitude of the B-47.

Since we know the B-47 was above the F-89's 20,000ft it was presumably leaving a jet contrail not an aerodynamic contrail, and the typical minumum for this is given as about 26,000ft. The likely max altitude of the B-47 would be the service altitude or about 33,000ft. So the trail would have been somewhere between 6000ft and 13,000 ft above the F-89.

The initial elevation angle of the object from the F-89 cockpit was 45 deg. Taking this as indicative we could infer (ht / SIN 45deg) a slant distance from the F-89 in the range 8600 - 18, 600 ft.

The angular size of the object is given as a dime at arm's length, which assuming 0.7 / 33 inches is about 1.2 deg, implying a physical diameter 170 - 370 ft.

This is huge. The B-47 was on the same 180 deg heading as the F-89, which was therefore below and behind it. The B-47 is 107ft long and 116 ft across the wings, The object would have completely dwarfed the B-47, being not only in the region of twice its physical size but also significantly nearer than the B-47 (below and behind it).

It seems unlikely that this would not have been noted, or that the position of the object in relation to the B-47 trail would have been in any doubt. Perhaps the angular size of > twice the size of the full moon is overestimated? This would be the norm.

The observers said they had thought it might be a "possible balloon of some sort" and ATIC tried to make that work although no known weather balloon was in the area. And the high power climbing pursuit with a total time in sight of ten minutes seems to rule out a nearby balloon. The obhect was sighted 90 deg to the right of the F-89 course therefore at 270 due West. The file says the object itself appeared to be on a heading of 270 deg, and the pilot turned to pursue on a heading of 270 deg at 250 kt, apparently for several minutes, but the object appeared to "pull away and up". Moreover the winds at all reported a;ltiudes from 5 to 45,000 ft were from the SW (200-210 deg) so the 270 deg heading would be substantially against the wind, making nonsense of the claim that "size, shape, ascending, westerly course are characteristics of balloon sighting" and the particular balloon they came up with - the best they could do, launched 5 hours earlier from Vernalis, Ca.

The impression given is that the object stayed at about the same bearing from the F-89 from the first sighting and that they abandoned the attempt to close and left it there, still visible as they headed back north. One wonders if the apparent position below the contrail could have been an illusion? Could it have been a much larger object moving slowly at much greater distance and altitude? If so one possible candidate is the Moby Dick balloons being launched around this era. It was desctibed as "clear silver" in appearance, which might fit the reflectivity of polyethylene in sunlight. Note the comment from the Director if Intelligence, 28th Air Div., regarding a balloon from a possilble "Air Force demonstration elsewhere".

Perhaps Joel or someone can comment on that possiblity?

Martin Shough


From: Joel Carpenter <>
Date: Fri, 16 Dec 2011 14:46:07 -0500
Subject: Re: [Current Encounters] Aug, 21, 1956; near Hamilton AFB, California (BB): AVCAT

Hi Martin,

Most of 1956 seems to have been a lull for Air Force balloon activity
after the big efforts leading to the recon project over Russia in
Jan-Feb. If this UFO was a large plastic balloon, it was either some
stand-alone project, or possibly a Navy flight. There were projects
called Grab Bag and Ash Can that collected emissions from nuclear
reactors and weapons tests that continued after Moby Dick stopped.
Also, it's obvious that something was going on at NAS Vernalis, a
short but intensive special launch effort called BARBERSHOP (no info
on which service sponsored it or what it was for), earlier in August.
Also one of the infamous Anthropomorphic Dummy drops at White Sands,
NM the same day as the sighting. But it's hard to believe any of those
would have been in the area of the sighting on the 21st.



From: "Martin Shough" <>
To: <>
Date: Fri, 16 Dec 2011 20:42:59 -0000
Subject: Re: [Current Encounters] Aug, 21, 1956; near Hamilton AFB, California (BB): AVCAT

Thanks, Joel. It occurs to me that one reason it might have been a question whether the object was above or below the contrail is if it was translucent. This would fit the description quite well. When you think about it the words "clear silver" are actually a little odd for an opaque solid but would fit a clear plastic. Given that they did at first think it might be "a balloon of some sort"; that the 28th Air Div DI advised about balloon launches from some "demonstration elsewhere"; that ATIC fingered NAS Vernalis as the source of a balloon; that the local winds argue strongly against a small nearby weather balloon; and that the failure to close during interception at 250kt could fit a sighting of a very distant large balloon ... given all this, the fact that Vernalis was operating some kind of unusual balloon programme assumes significance. So I'd be inclined to log this as "possible large balloon". Does anyone disagree?



Date: Sat, 17 Dec 2011 06:29:43 -0500 (GMT-05:00)
From: Jan Aldrich <>

I think this might have been a 4602nd AISS case. I copied only a sample of the files. I don't find a copy in my files. The 4602nd at this date did not provide Project BB with much backup material unless the case was unidentified and needed further analysis. Any questionaires or addition details might be in these files which are not on microfilm or readily available to the public.

Jan Aldrich


Date: Sat, 17 Dec 2011 12:15:10 -0000
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Thanks Fran.
I notice that on the main page it is carried as Rating 5

1 - Explainable or explained
2 - Probably explainable with more data
3 - Possibly explainable, but with elements of strangeness
4 - Strange; does not conform to known principles
5 - Highly strange: suggests intelligent guidance

This is supposed to be the average of all analyst ratings. I don't personally know of any analysis except by myself, Joel and ATIC, and I would guess (Joel can speak for himself) that an average of these would put it somewhere around 2 or 3, maybe 2 1/2 - Possibly or probably explainable with more data, though with elements of strangeness. Are there other sources not mentioned?

The only thing that might suggest "intelligent guidance" is the failure to close in intercept. This *can* be interpreted as a nearby object "pulling away" from the F-89, but can also fit a distant large object. Note the answers to the AFR 200-2 question 2 which give the apparent heading of the object when pursued (up and away in a straight line) as being the same as the position, i.e. the inferred motion was always in the line of sight. They climbed straight at it, at 45 deg elevation, yet the two crew disagreed about whether the object itself was climbing or not. But if it was an evasive nearby object flying directly away from their own 45 deg climb at 250kt IAS as stated, then of course it must have climbed or they would have overhauled it. On the other hand if it was really a very large balloon tens of miles away and miles above them, they would not reach it in a couple of minutes of climb but the apparent size of the object ought to have increased proportionately to the distance travelled (maybe order of 1/10). The pilot said that when they broke off the attempt to head home the object did appear larger.