Detonated:    6 February 1951    

Time:     1347    GMT

TYPE OF DETONATION:     Airburst    
 
ALTITUDE OF DETONATION:   440  m (above ground) 
 
REPORTED YIELD:     22    kilotons 
 
RADIOIODINE (I-131) PRODUCED:   3.2 x 10E6 Curies 
 
STABILIZED CLOUD HEIGHT:  Top  12.8  km, msl;  
                          Base  No Report  
 
MEASUREMENTS AVAILABLE FROM GUMMED FILM COLLECTORS:  No  
                                                    
 
RADIOIODINE IN COUNTIES WITHOUT GUMMED FILM COLLECTORS  
     ESTIMATED BY:    Meteorological Model   
 
CLOSE-IN FALLOUT PATTERN AVAILABLE:  No     
            Trajectory and Fallout Characteristics 
 
 
                                Ranger, Fox. 
 
 
Close-In Fallout 
 
     No close-in fallout data have been located for this test. 
 
Town Data Base 
 
     No Town Data Base observations have been located for this test. 
 
County Data Base 
 
     No County Data Base fallout estimates were made for this test. 
 
Upper-Air Trajectories 
 
 
     Upper air trajectories were started from NTS at four levels (5.5 to 12.2 
km) by Machta et al (1957) at the time of detonation.  Since the yield was 
nearly three times that of the other two Ranger tests presented here, a 12.2 km 
trajectory was included in the trajectory analysis in anticipation of a much 
higher debris cloud top.  A 3.0 km trajectory was calculated by use of upper air 
charts especially for this test to complete the trajectory set for this report. 
 
     All trajectories, 5.5 km and above, moved toward the south-east, initially, 
between 8 and 10 m s-1 but quickly accelerated to considerably higher speeds 
(Fig.RA/3/T). The highest three crossed the Texas coast near Corpus Christi near 
the end of the first day after the explosion (1347 GMT, 6 Feb. to 1800 GMT, 7 
Feb.). They crossed Cuba near the end of the second day then crossed the Bahamas 
early on the third day. The slower 5.5 km trajectory followed nearly the same 
track but turned to the left in the Gulf just north of the higher three 
trajectories' tracks. It did not reach Key West until early on the fourth day.  
Turning slowly to the left, it was extended for this report to a point 950 km 
east of Cape Hatteras.  Unlike the others, the 3.0 km trajectory moved slowly 
southward into southern California, made a tight clockwise loop, then headed 
eastward across central Arizona on the second day after detonation (1800 GMT, 7 
Feb. to 1800 GMT, 8 Feb.). Turning to the southeast it reached El Paso, Texas, 
(early on the third day), and proceeded along the Rio Grande River to Great Bend 
(Texas) and turned to the south-southwest into Mexico late on the third day.   
 
     The Deposition of radioactive iodine (I-131) across the United States was 
estimated by the Meteorological Transport and Deposition Model because no 
ground-level radioactivity detection system was deployed for the Ranger test 
series. This model is described in Hoecker and Machta (1990) and in Chapter 3. 
 
     Only small areas of the United States received any I-131 fallout from this 
test according to the model. A moderate amount (10 - 27 nCi m-2) was deposited 
in one isolated county in central New Mexico. The major deposition occurred in 
an arc-shaped area extending inland from the northern Gulf coast between Corpus 
Christi, Texas, to Georgia. This area extended inland as far as northern 
Louisiana and covered the southern two-thirds of Missis- sippi and Alabama.  It 
had mainly spotty depositions of light to moderate (10 - 27 nCi m-2) fallout.  
Surrounding this area and interspersed among the light to moderate deposition 
areas was very light fallout (1 - 3 nCi m-2). Scattered areas of very light 
fallout covered much of Georgia and some of southern North Carolina. 
 
     Florida had areas of very light to light fallout south of Cape Canaveral.  
These depositions were derived from that portion of the radioactive debris cloud 
stretched between the 3.0 and 5.5 km trajectories that lay over the area on the 
sixth day after detonation (about 0600 GMT, 11 February). 
 
 
                            References 
 
Hoecker, W.H. and L. Machta, 1990: Meteorological modeling of radioiodine 
transport and deposition within the continental United States. Health Physics, 
59(5): 603-617. 
 
Machta, L., H.L. Hamilton, Jr., L.F. Hubert, R.J. List, and K.M. Nagler, 1957: 
Airborne measurements of atomic debris. Journal of Meteorology, 14(4): 165-175.  
 
Figure RA/3/T. Estimated trajectories, at several altitudes, of the radioactive cloud resulting 
               from the test FOX of 28 February 1951.  Numbers indicate the position of each 
               trajectory at 0000 GMT for several days following the explosion. 
 
Figure RA/3/F. 
Figure RA/3/CD.