Tsu Shima, Japan, September 1952September 1952

Insufficient Data

Summary

# Summary

In September 1952, radar operators at Tsu Shima, Japan, detected an unusual radar signature on several occasions. When military aircraft made outbound flights from nearby Itazuke Air Base, a series of radar targets appeared directly behind each plane as it passed through a particular airspace. The targets looked roughly like a normal aircraft on radar but were rounder in shape, and they maintained a distance of approximately two to three miles behind the main aircraft being tracked. The operators noted these echoes appearing and disappearing within two to four radar sweeps, with no indication of independent speed or direction.

The radar signatures were recorded on multiple passes: at 2035, 2041, 2050, 2052, 2156, and 2209 hours (all times in local time). Two radar operators, Airman Hall and Airman Groverstein, observed the phenomenon. Both called attention to the unusual presentation, though the site's scope was otherwise normal, with only minor sea clutter visible. Not all aircraft passing through the same area produced these echoes. Notably, no aircraft managed to intercept any physical object, and no physical evidence was recovered.

The Air Force's investigation concluded that the radar presentation was likely caused by atmospheric changes (ionization and extraneous radar echoes) triggered as the aircraft passed through that particular area. This explanation was offered by the Deputy for Intelligence at the 527th Air Control and Warning Group, the unit responsible for the radar station. The file's conclusion checklist marks the sighting as "Probably Balloon," though the actual investigation focused on atmospheric and radar propagation effects rather than any observed object.

The complete case file is reproduced below as held by the National Archives, comprising 12 pages.

Reported location

Tsu Shima, Japan, September 1952

Date of incident

September 1952

State / country

? / XX

Page count

12 scanned pages

USAF evaluation

unknown

Microfilm

T1206, Roll 15

JTS CL ————— ER EE SS EE geist SR BE BED SS ODE idiom in Dei | PROJECT 10073 RECORD CARD : 1 DATE : ( 2 12. LOCATION ( 112. CONCLUSIONS | _ 22 800 She Tsu Shima, Japan CG Was Balloon ii {Q Probably Salloon | 3. DATE-TiuE GRIVP "4 TYPE OF OBSERVATION 1Q TNT. Sewn | . Ll ~ 1 ap mb | “eral RIL TR oe , 0B Ground-Visvel L Grounc-Redor ‘a Paatte Avih | 1 Ter ATR gad 5 Ave Visual 0 Aur-intercept Radar 1G Possibly Mierais *5. PHOTOS “V8. SOURCE sy “G0 Wes Astronomicel ! C Yas i ‘01 Probobly Autrenomical i \ military © Possibly Asrrennamica. | Es C No PRs ~ : ried JERS '7. LENGTH OF CBSERVATION 8. NUMBER OF OBJECTS ' 9. COURSE 3 Other bea 43 oth ! ' 5 insuificient Data ror Evaluator ] - : i & Uni Ow 1 hr 34 minutes. : several | gee SECRETIN AR TR | otis donations oi i ms des soe ig es ie Sn ees ES + ln SOS A A ree ein ite vos SE rm le @ PO BD DN oF as gar ine (10. BRITF SUMMARY OF SIGHTING 11. COMMENTS peCalaliin : : . we . | foOn two @parate outbound tracks roa | DfT ¥F3NF CCITT - The presentation | itazuka AD, a series of targets appeared appears to be due to Luocphere chance : directly venind the alrcraly wun entering | caused Ly passage of the tarzet a/c an azimuth of 050° to 076° in ra2lation to | through this particular area, resuliiny : TTU, SAKI. OCbjJects appeared as a noraal in ionization and extraneous cchoes. ; | i a/c, but rounder in shape vith a trace and | 1Y | trailed approx 2-3 miles '° aar ot a/c. , | | | AR | i SERINE CRT TN A ROA 0 1 BRE | ATIC FORM 129 (REV 36 SEP 52) PE ———— C—O Ha AD SE — C—O er Wa mw