SR-91 Aurora: The Supposed Mach 5 Plane That Was Never Officially Confirmed

SR-91 Aurora was a top-secret project that was probably never more than a prototype and remains classified to this day.
Aurora x-plane

The Aurora is little more than a myth to this day because there are still no official reports about its existence. However, many sightings of this mysterious aircraft in 1989 opened speculations about its existence.

Little has been revealed about this aircraft… and officially, the SR-91 Aurora didn’t ever exist. But many experts claim it flew– at least as a prototype.

The unclear existence of the SR-91 Aurora

SR-91 Aurora x-plane
SR-91 Aurora x-plane by Henrickson. Licensed under CC by 3.0

The most well-known event that suggested that the aircraft was actually real was the sighting of a triangular-shaped aircraft over the North Sea in 1989 by oil exploration engineer Chris Gibson. 


However, this report is not even 100% reliable because Gibson could have confused the mysterious SR-91 Aurora with the sighting of a B-2 Spirit – which indeed has a triangular shape, and its bizarre design would shock anyone in the 80s.

B-2 Spirit
B-2 Spirit by Devin Doskey. Public Domain.

Moreover, Gibson could confuse the SR-91 Aurora with a Lockheed F-117 Nighthawk, which also has an unconventional shape.

F117 - RIAT
F117 – RIAT by Airwolfhound. Licensed under CC by 2.0

In the end, the SR-91 Aurora remains an enigma. Almost nothing has been published to indicate that there was ever even a real project – and certainly, this aircraft may have been mistaken with other oddly shaped aircraft.


What is currently known about SR-91 Aurora

Aurora spyplane
Aurora spyplane by Henrickson. Licensed under CC by 3.0

In the 1980s, military strategists envisioned the idea of creating a hypersonic spy plane that could exceed Mach 5, which would make it the fastest manned aircraft ever to fly with a service ceiling of 90,000 feet (27,432 meters).

As a result, the Aurora was born. But, this aircraft may have been an unfinished design that went no further than a prototype at a time when unusually shaped aircraft such as the F-117 Nighthawk, B-2 Spirit, or SR-71 Blackbird was being tested.

SR-71 Blackbird: the Cold War spy aircraft that inspired the Aurora creators

sr -71 blackbird
sr -71 blackbird by Public Domain.

The Blackbird was a spy plane designed to safely fly over hostile territory without being shot down or even spotted due to its immense speed of up to Mach 3.2. It was designed as a reconnaissance plane in an era before spy satellites.


The Lockheed SR-71 was able to fly close to the edge of space and outrun any missile of Soviet design.

In fact, it currently owns the record for the highest speed and altitude for a non-rocket-powered aircraft with 85,069 feet or 25,929 meters and a record speed of 3,529.6 km/h or 2,193.2 mph.

It was secretly built by Lockheed, made entirely of titanium, and painted black (that’s why it was nicknamed the Blackbird) because it had to be made from a material that could withstand extremely high temperatures. Titanium was the only option due to its low weight and high melting point.


But, this state-of-the-art aircraft used to cost $300 million per year to run. Probably, for this reason, the Aurora prototype has probably started development.

The end of the Cold War and the development of the satellite canceled spy plane projects

The Blackbird airframe featured some of the first composite materials ever employed in an aircraft, resulting in an aircraft being hard to detect by enemy radars, and it is believed the Aurora had similar characteristics.

Additionally, flying at an altitude above what anti-aircraft missiles could reach and faster than a missile, the Blackbird could enter hostile airspace virtually unchallenged.


But, in the age of satellites, having spy planes costing hundreds of millions of dollars a year to operate and maintain was no longer necessary.

Spying activities could very well be done from satellites, and this meant that money for high-speed, extremely costly to fly and maintain, wasn’t available anymore.

Presumably, this is the reason the Aurora never made it to mass production, and it didn’t become an official USAF model.


The Aurora remains a mirage in the sky

This almost mythical aircraft has given much to talk about with its uncorroborated sightings… and because of its status as a top-secret project, we may never know the truth about this fascinating aircraft.

In any case, the qualities attributed to the Aurora are impressive, and an aircraft capable of flying at more than five times the speed of sound would impress any nation’s air force in the world. 

In the future, we might see a similar design to the SR-91 Aurora, the Lockheed Martin SR-72 “Son of Blackbird,” which will finally overcome the speed of the Blackbird and the supposed Mach 5,5 of the Aurora.


Feature image credit: Aurora x-plane by Henrickson. Licensed under CC by 3.0

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