AARO Resolves Aguadilla Sphere as Sky Lanterns

Brief

On April 26, 2013, a U.S. Customs and Border Protection infrared sensor aboard a De Havilland Canada 8 aircraft recorded two objects drifting near Rafael Hernandez Airport in Aguadilla, Puerto Rico; the footage circulated publicly as evidence of a transmedium UAP. AARO's Systems Toolkit reconstruction determined the objects moved in a straight line at approximately 8 mph, consistent with the recorded wind speed of 9.8 mph, and remained over land throughout, ruling out the reported water-entry. Apparent high speed was attributed to motion parallax caused by the aircraft's own movement, and apparent splitting was determined to represent two distinct objects traveling in proximity the entire time. AARO assesses with moderate confidence the objects were sky lanterns, citing size estimates under one meter, fluctuating thermal signatures consistent with burning fuel, and vendor confirmation that lantern releases are standard practice at local hotels and resorts.

Metadata

Agency

DoD / All-domain Anomaly Resolution Office (AARO)

Release

2023-01-01

Type

PDF • .pdf

Length

7 pages

Classification

UNCLASSIFIED

Programs

Systems Toolkit (STK)

Tags

sky lantern, infrared, Puerto Rico, 2013, transmedium claim, thermal crossover, motion parallax, CBP, De Havilland Canada 8

Key points

• STK reconstruction placed object speed at approximately 8 mph, matching the recorded wind speed of 9.8 mph from the east/northeast, consistent with passive drift, not propulsion.p.3
• Objects remained over land throughout the encounter; apparent water entry was caused by thermal crossover reducing contrast between the objects and the ocean background.p.3
• Apparent splitting behavior is assessed with high confidence to represent two separate objects traveling near each other, with visible separation events timestamped at 00:29.56, 00:40.76, and 00:47.00 seconds.p.3
• Motion parallax, induced by the aircraft's flight speed, sensor zoom, and changing relative position, accounts for the objects' perceived high velocity.p.3
• Pixel analysis estimated both objects at under one meter (three feet), consistent with sky lantern dimensions.p.5
• Thermal crossover conditions were active at time of recording: sunset occurred at 7:48 p.m. local time; IR footage was captured at 9:22 p.m., within the two-hour crossover window.p.6
• Three compounding sensor effects degraded IR fidelity: thermal crossover, a nearly tripled sensor-to-object distance, and scattered cloud cover at 3,000 ft.p.6
• AARO formally evaluated and rejected three alternative hypotheses: anomalous phenomena, marine birds, and mylar balloons.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

• The reconstruction demonstrates that the objects remained over land during the encounter.

  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

• IR signatures can appear to "vanish" when the thermal contrast between the object and background becomes indistinguishable (Figure 4).

  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 does not concur with this assessment, because it is unlikely that an IR sensor could detect reflected moonlight.

  p.7

Most interesting

• The footage was captured by U.S. Customs and Border Protection, not a military unit, and circulated publicly before AARO formally investigated it more than a decade later.
• The CBP aircraft gained 1,725 feet in altitude during the encounter while the distance between aircraft and objects nearly tripled, directly degrading sensor quality as the video progressed.
• An AARO partner agency assessed the objects as marine birds traveling between 35 and 130 mph, a range AARO rejected after its own STK reconstruction showed straight-line drift at wind speed with no wing features detectable.
• The incident occurred in 2013 but was not formally resolved until March 2025, a twelve-year gap between footage capture and case closure.
• AARO used pixel analysis to rule out one dramatic alternative: that the objects passed behind a utility pole, which would have indicated far lower altitude and far higher speed than assessed.
• Sky lantern thermal signatures gradually weaken as fuel is expended, which explains the objects' diminishing IR return, a pattern AARO found consistent with the footage's declining image quality over time.