Dept. of DefenseUnresolvedAnomalous kinematics

High-speed white substance observed by RB-29 crew — estimated 4,200 mph, Pacific

Jun 8, 1949Pacific Ocean, 12°25'N, 140°20'E30,000 ft60s

Analysis — our summary

On June 8, 1949, crew of RB-29 from the 514th Reconnaissance Squadron (weather reconnaissance mission Vulture Baker) at 18,500 ft observed a white billowing substance at 30,000-35,000 ft. Two crew members — 1st Lt. Ernest Swanson (weather observer) and Sgt. Walter Rogers (engineer) — watched a traveling contrail-like substance moving ENE to WSW, estimated by triangulation to travel at approximately 4,200 miles per hour. The substance was observed for about one minute. No sketches or photographs available.

As reported — verbatim from the document

“What appeared to be a traveling contrail was moving from east north east to west south west at an estimated speed of 4200 miles per hour, this speed was determined by means of triangulation... The substance was traveling in a straight line and was definitely white.”

Analyst notes — caveats & confidence

Speed estimate of 4,200 mph by triangulation from a single moving aircraft platform is inherently imprecise and potentially unreliable. A contrail-like substance at high altitude could have multiple explanations including a rocket test or atmospheric phenomenon. Two witnesses.

Provenance

Source document342_HS1-416511228_box186_319.1-Flying-Discs-1949.pdf

Document typeadministrative correspondence

Reporting agencyDept. of Defense

Source pages143

DeclassifiedFirst public at this release (2026)

Held classified~77 years (≥, to this release)

Extraction confidence ModerateHow cleanly this record could be parsed from the source — driven by legibility & redaction. It is not a measure of how credible or anomalous the sighting is.