AARO Website Launch: Puerto Rico Resolution

Brief

On April 26, 2013, a U.S. Customs and Border Protection infrared sensor aboard a De Havilland Canada 8 aircraft near Aguadilla, Puerto Rico recorded two objects that public claims described as splitting, accelerating to high speed, and entering the Atlantic Ocean. AARO's Systems Toolkit reconstruction placed object speed at 8 mph, consistent with recorded wind, and showed the objects remained over land throughout. Apparent high speed is attributed to motion parallax, the apparent splitting to a side-on-to-top-down sensor angle shift as the aircraft climbed, and the apparent ocean-entry to thermal crossover within the two-hour post-sunset detection window. AARO assesses with moderate confidence the objects were sky lanterns, corroborated by local hospitality-industry vendors confirming routine releases at hotel celebrations.

Metadata

Agency

All-domain Anomaly Resolution Office (AARO), U.S. Department of Defense

Release

2023-08-31

Type

PDF • .pdf

Length

7 pages

Classification

UNCLASSIFIED

Programs

Systems Toolkit (STK), Minimum Separation Vectors

Tags

sky lanterns, infrared sensor, Puerto Rico, 2013, transmedium (claimed), motion parallax, thermal crossover, AARO case resolution, CBP aircraft

Key points

• Objects assessed at 8 mph via STK reconstruction, consistent with the recorded wind speed of 9.8 mph from the east/northeast; apparent high speed is produced by motion parallax from the moving aircraft.p.3
• STK reconstruction demonstrates the objects remained over land throughout the encounter, directly refuting the transmedium (ocean-entry) claim.p.3
• AARO assesses with high confidence the video captures two objects traveling together the entire time, not a single object splitting, visible separations occur at 00:29.56, 00:40.76, and 00:47.00 seconds.p.3
• The aircraft's altitude gain of 1,725 feet and a near-tripling of sensor-to-object range during the encounter are identified as primary drivers of the footage's diminishing quality and apparent anomalies.p.1
• Pixel analysis estimates both objects are smaller than one meter (three feet) with indistinct shapes; pixel analysis also ruled out the hypothesis that the objects passed behind a utility pole.p.5
• Sky lantern attribution is supported by vendor interviews confirming that hotels and resorts near Rafael Hernandez Airport routinely release sky lanterns, and by the objects' flickering, weakening IR signatures consistent with fuel burn.p.5
• The recording was made at 9:22 p.m., within the two-hour post-sunset thermal crossover window (sunset at 7:48 p.m.), explaining IR loss of contrast near the ocean background.p.6
• AARO rejected a partner's marine-bird hypothesis because STK shows straight-line wind-speed travel, and birds at these distances would retain wing-structure features or show wingbeat pulsation in IR.p.7
• AARO rejected a mylar-balloon hypothesis from a separate partner, disagreeing that an IR sensor could detect reflected moonlight from balloon surfaces.p.7

Verbatim

• Motion parallax is an optical effect that induces an observer to perceive that a stationary or slow-moving object is moving much faster than its actual speed when viewed from a moving frame of reference.

  p.3

• AARO confirmed with local hospitality industry vendors that it is common practice for hotels and resorts in the area to release sky lanterns during celebrations.

  p.5

• Thermal Crossover: This natural phenomenon reduces the effectiveness of thermal imaging systems in detecting the contrast between an object and its environment during and after a rapid temperature change, such as during sunrise and sunset.

  p.6

• AARO is not a member of the intelligence community. This AARO information report should not be considered finished intelligence.

  p.7

Most interesting

• Three separate analytical partners reached three different conclusions, anomalous phenomena, marine birds, and mylar balloons, before AARO settled on sky lanterns; none of the partner attributions were adopted.
• The CBP footage had already circulated publicly before AARO's investigation, making this a rare case where the primary source was open-source media rather than classified reporting.
• The sensor's shift from a side-on to a top-down viewing angle as the aircraft climbed is identified as the geometric reason the 'split' appeared most dramatic near the end of the video, the opposite of what a genuine splitting event would produce.
• Thermal crossover, which can persist up to two hours after sunset, is cited from a peer-reviewed Optics Express journal article (Felton et al., 2010), giving the sensor-limitation argument a published empirical basis.
• The apparent 'vanishing into the ocean' is explained entirely by a loss of thermal contrast between the lanterns and the ocean surface, not by any water-entry, the objects simply became indistinguishable from their background.
• The case was originally reported as an incident from 2013 but was not formally resolved by AARO until March 20, 2025, a twelve-year gap between event and official closure.