Two Weeks Before Bomb Effect Known

Press, Volume CI, Issue 29871, 11 July 1962, Page 13

Two Weeks Before Bomb Effect Known

(A.Z. Press Association—Copyright) HONOLULU, July 10.

I he United States Atomic Energy Commission said yesterday that it would take scientists at least two weeks to determine what, if anything, Sunday night’s high-altitude hydrogen bomb test explosion over Johnston Island did to the Van Allen belt, the natural zone of radiation around the earth.

Scientists were inclined to doubt that it had any measurable effect on the \ an Allen belt, which consists of charged particles trapped in the earth’s magnetic field, I nited Press International reported.

Information about the effect if any on the Van. Allen belt will come from two satellites carrying equipment to measure particle energies and intensities. It will take two weeks or more to process and analyse their data, it was said.

The satellites are Injun, launched on June 29. 1951. and TRAAC. launched on November 15, 1961 Injun carries instruments designed by Dr. James A. Van Allen.

the State University of lowa physicist after whom the radiation zone was named. Four of the Cosmos series of Soviet scientific satellites are still in orbit. But according to the latest information available from the National Aeronautics and Space Administration only one is still transmitting Cosmos V. launched on Mav 28

Little disruption of radio communications by the shot was reported by Federal agencies in Washington. The Strategic Air Command said it experienced no in erruptions. and the Federal Aviation Agency said hardly any communication effects were noted by its officials in the general area of the test.

The Van Allen E>elt dips to an altitude of about 4CO miles a: its nor hern and southern extremities and rises to about 2000 miles over the Equator Space scientists have estimated that the bottom of the zone is 745 to 870 miles high over Johnston Island. The test is believed bv some to have been about 500 miles below the belt. Hawaiian Theory

Scientists in Hawaii estimated that the bomb exploded a record 400 miles in space. U.P.I. reported.

The huge fireball, 700 miles away, was seen clearly last night by scientists on top of 10.000-foot Mount Haleakala on Maui, an observation point from which altitudes of previous explosions have been computed accurately. If the Hawaiian estimate proves correct, it would be the highest United States nuclear test The highest previously announced were 300 miles, with much smaller explosions

In Washington. Atomic Energy Commission officials remained silent on whether an even higher space test would be attempted in the near future—the long-expect-ed “rainbow bomb.”

Yesterday’s test, acknowledged officially to have been of a thermo-nuclear or hydrogen bomb type, took place at an altitude of "hundreds of kilometres," accord-

, would take at least a year i even to begin falling on the earth, scientists estimated. i It would take about five years ! for the first half of it to ‘come down, the Associated I Press reported. ; The A.E.C. refused to make i any sort of an estimate on how much fallout will result i from the blast. Its reasons i were: (!) The A.E.C. will not say just what percentage of I the megaton-range device produced fission j energy, as distinguished l from fusion. The fission is the part that produces the major share of the fallout from a nuclear I explosion. (2) Scientists still disagree, the A.E.C. says, on what happens when a weapon is detonated in the fringes of outer space, as distinguished from one detonated in the earth’s atmosphere or on or near the earth's surface. One view is that about half the radioactive debris from a nuclear explosion ar ! an altitude of several hundred miles would shoot far out into space and never return to the earth. The only official view of the amount of fallout which

mg to the A.E.C. 7 he nuclear device, shot; aloft aboard a Thor booster i rocket, was officially placed j “in the megaton range." giv-, ing it a force equal to at ’ least 1.000.000 tons of T.N.T. but unofficial reports put it; at 10 megatons. No Comment Officials would not give the j exact height. Nor would they ■ comment on a statement by I Dr. D. M. Gadsden, of the j auroral research station at! Lauder. New Zealand, that i he thought indications were, that the momb went off at an i altitude of 1400 miles Although it may not have ‘ disturbed the Van Allen belt, j the explosion undoubtedly did distort magnetic lines of force in the Johnston Island area and may have created a, temporary thin shell of electrons in the magnetic field. The A.E.C. and Defence Department sent up a number of rockets from Johnston Island at tihe time of the shot to gather information on its effects, both scientific and military Scientists today were also examining the fallout potential for the test. Whatever radioactive fallout resulted from the test, it

would eventually reach the earth from the test was the statement of President Kennedy that the current series of tests in the Pacific would contribute only very small amounts of fallout as compared with that produced by the Soviet Union’s latest atmospheric tests. Many scientists in the United States were amazed at the intensity of the longrange effects of the blast, the “New York Times” reported today. However, they saw in the effects no conceivable harm to the earth’s inhabitants.