Data on the nuclear test in question is as follows, extracted
from this URL:

http://www.envirolink.org/issues/nuketesting/hew/Usa/Tests/Dominic.html

note this is a longish URL and may wrap around if your mail window isn’t
wide enough… The highest level of this URL ahs a considerable amount
of history of nuclear weapons, btw.

Also at this location is data on the Swordfish test of a live nuclear
ASROC from
the USS AGERHOLM (FRAM GEARING class) and several photos of this test
including
an ovehead view of the spray dome which I had not previously seen.

“The Soviet Union had abrogated the 34 month old de facto nuclear
testing moratorium on 1 September 1961 by
initiating an unprecedented series of atmospheric nuclear
tests….Numerous atmospheric tests, many at high yield, were of course
on the drawing board at the weapons labs, some
carried over from planning for previous test series. Official U.S.
action on convening its own atmospheric series did
not begin until 10 October 1961 when President Kennedy approved
planning for one. Final approval was given on 2
March 1961, 7 weeks in advance of the first planned test.

” Dominic included 36 tests…..Conducted as part of Operation Dominic
was a series of high altitude tests known as Operation Fishbowl. These
tests
were Thor missile launched warheads detonated at very high altitudes
(30-248 miles) to evaluate the destructive
mechanisms and effects of high yield explosions against ballistic
missile RVs.”

After going through each of several air-dropped Dominic tests in some
detail, we eventually get to this:

“Test:Starfish Prime
Time: 9:00 9 July 1962 (GMT)
Location: Johnston Island
Test Height and Type: Missile Airburst; 248 miles
Yield:1450 Kt

Device Diameter (inches):20
Device Length (inches):54.3
Device Weight (lb.):1665

“This was the second attempt to launch the Starfish test. The original
Starfish was launched on 20 June, but the Thor
missile engine cut out only 59 seconds after launch. The range safety
officer sent the destruct signal 65 seconds after
launch, and the missile was destroyed at 30-35,000 ft. The warhead high
explosive detonated in 1-point safe fashion,
destroying the warhead without producing nuclear yield. Large pieces of
the missile fell back on Johnston Island, and
more wreckage along with plutonium contamination was found on nearby
Sand Island.

“Starfish Prime was successful. The Thor missile carried the test
instrumentation and the W-49 warhead/Mk-4 RV
payload to 248 miles. The test appeared quite spectacular from Hawaii
(800 miles away) and at Kwajalein (1600 miles
away), with impressive light displays from an artifical aurora lasting
up to seven minutes. The electromagnetic pulse
(EMP) from this test sent power line surges throughout Oahu, knocking
out street lighting, blowing fuzes and circuit
breakers, and triggering burglar alarms.

“The W-49 warhead used in this test was used on the Thor, Atlas,
Jupiter, and Titan missiles, and was a descendant of
the versatile Mk-28 thermonuclear bomb.”

The two phtographs provided showing the aurora-like visual effect of
this test are at URL’s:

http://www.envirolink.org/issues/nuketesting/hew/Usa/Tests/Dstarfish1s.jpg

and as above but /Dstarfish2.jpg

-Brooks