Moon Rocket Gave No New Radiation Data

Press, Volume XCVII, Issue 28728, 28 October 1958, Page 11

Moon Rocket Gave No New Radiation Data

(Rec. 10 p.m.) NEW YORK, October 27. Analysis of data from the Explorer satellites had revealed a complex but symmetrical shape of the' regions of intense radiation near the earth, said a report from lowa City, lowa, in the “New York Times” today.

But, contrary to earlier belief, the moon rocket, Pioneer, fired on October 11, added little to present knowledge of the phenomenon. No usable information on radiation appeared to have been received from the vehicle until it was 18,000 miles from the earth. By then it had passed beyond the radiation zone. What the Pioneer did show was that at that distance and beyond there was virtually no radiation. Initial reports on the Pioneer’s information mentioned moderate levels of radiation in this region, but corrections made in lowa City for instrument errors showed the readings to be zero. Responsibility for planning and analysing the satellite and moon rocket exploration rested with the physics laboratory of the University of lowa, under the direction of Dr. James van Allen. Recordings of the Pioneer’s signal had been received at the university from all the stations primarily responsible for following it toward the moon. In al] cases background noise spoiled the data signals to the 18,000 miles. Mr Carl Mcllwain, who was plotting much of the data, said he clung to the “forlorn hope that a tape recording made near the launching site at Cape Canaveral, Florida, might fill in part of the gap. The Pioneer's batteries went

dead eight or 10 hours before it came back to earth, and hence no data were available for its return through the critical 18,000 miles. It was reported that part of the difficulty in obtaining a clear signal from the Pioneer was the existence of an unsuspected minor defect in the giant radio-telescope at Jodrell Bank, England, which followed the rocket for the first several hours of the journey, but apparently did not receive the signal at full strength. Mr Mcllwain already had plotted enough information from the Explorer satellites to construct a diagram showing the pattern of the radiation. It was reported after the Pioneer’s flight that the maximum intensity of radiation seemed to lie about 5000 miles from the earth. Mr Mcllwain and Dr. Ernest Ray, Dr. van Allen’s deputy, were sceptical. of this. They did not think the Pioneer’s data supported it, and pointed out that the Pioneer’s flight path did not pass near the equatorial plane of the earth’s magnetic field. This geomagnetic equator formed, roughly, a circle connecting those points on the earth’s surface equidistant from the magnetic poles. It was near this plane, they believed, that the most intense radiation would be found.