Final Product (FOIA 23-F-0010)

They were characterized by a size of3-12 meters and speeds up to 15 kilometers per second at a
distance ofup to 10-12 kilometers. If real, such objects exceed the capabilities ofhuman-made
aircrafts or rockets. I quickly realized that the distance of these dark objects must have been
incorrectly overestimated by an order of magnitude, or else their bow shock in the Earth's atmosphere
would have generated a bright fireball with an easily detectable optical luminosity.
The interest in UAP stems from their potential non-human origin. Extraterrestrial equipment could
arrive in two forms: space trash, similar to the way our own interstellar probes (Voyager 1 & 2,
Pioneer 10 & 11 and New Horizons) will appear in a billion years, or functional equipment, such as
autonomous devices equipped with Artificial Intelligence (AI). The latter would be an ideal choice for
crossing the tens ofthousands oflight years that span the scale ofthe Milky Way galaxy and could
survive even if the senders are not able to communicate.
It is likely that any functional devices embedded in the Earth's atmosphere are not carrying biological
entities because these would not survive the long journey through interstellar space and its harsh
conditions, including bombardment by energetic cosmic-rays, X-rays and gamma-rays. Interstellar
gas and dust particles deposit a kinetic energy per unit mass that exceeds the output of chemical
explosives at the speed of tens of kilometers per second characterizing rockets. However,
technological gadgets with AI can be shielded to withstand the hazards of space, repair themselves
mechanically, or even reproduce given the resources of a habitable planet like Earth. With Machine
Learning capabilities, they can adapt to new circumstances and pursue the goals of their senders
without any need for external guidance.
As argued by John von Neumann in 1939, the number of such devices could increase exponentially
with time if they self-replicate, a quality enabled by 3D printing and AI technologies. Physical artifacts
might also carry messages, as envisioned by Ronald Bracewell in 1960.
In principle, the fastest gadgets could be launched by lightsails, pushed by powerful light beams up to
the speed of light. Natural processes, such as stellar explosions or gravitational slingshot near black
hole pairs, could launch objects to similar speeds. However, it would be difficult for relativistic
payloads to slow down below the escape speed of Earth, smaller by 4.5 orders of magnitude than the
speed oflight, without having around the same facilities that generated their high initial speeds.
A better suited propulsion technique that was used in all space missions from Earth is chemical
rockets. Since rockets carry their fuel, they can navigate to a desired planet and slow down near it.
The tyranny of the rocket equation, requiring that the fuel mass must increase exponentially with
increasing terminal speed, explains why all human-made spacecraft reached a speed limit of tens of
kilometers per second, 4 orders of magnitude below the speed oflight. Interestingly, this speed is
comparable to the escape speed from the Earth's orbit around the Sun, 42 kilometers per second,
making it possible for humanity to launch probes to interstellar space by taking advantage of the
motion of the Earth around the Sun at 30 kilometers per second. Chemical propulsion may not be
sufficient for probes to escape from the habitable zone around dwarf stars, like the nearest star,
Proxima Centauri.
In summary, chemical propulsion allows escape from the habitable zone of Sun-like stars and enables
slowing down near a destination. The Ukranian report suggests objects with comparable speeds of up
to 15 kilometers per second.
Devices which need to refuel would favor a habitable planet where liquid water or combustible
organic fuel are available. Planets can be identified from a distance as they transit their star or
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