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Declassified: 18 little-known facts about US Air Force stealth program (pictures)

This is how the B-2 Stealth Bomber, F-22 Raptor and F-35 Lightning II avoid detection from enemy radar and infrared.

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Fox Van Allen
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1 of 18 SrA Brian Ferguson/HQ AFNEWS

This is the first modern stealth fighter

Militaries have been pursing stealth aircraft technology since the advent of the airplane. But no one has mastered it quite like the US military.

This is the Lockheed F-117 Nighthawk. It's the first truly modern stealth aircraft...one that spent most of its life as a top-secret black project.

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2 of 18 Airman 1st Class Leah Ferrante/USAF

The creators called the design "hopeless"

The F-117 owes its unusual shape to the limits of 1970s computer technology; Lockheed had to make its sides flat and angular so its computer program could more easily minimize its radar cross section.

Lockheed scientists called its design the "hopeless diamond," diamond for its faceted shape and hopeless because of how difficult it is to stay airborne.

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3 of 18 USAF

The shape makes it impossible to pilot manually

These planes are designed around their stealth feature, not performance or aerodynamics. The F-117's design, for example, is aerodynamically unstable across all three of its axes.

This means the plane is impossible to pilot manually. Its onboard computers must constantly calculate and make flight corrections to keep it from crashing.

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4 of 18 USAF

The B-2 Bomber was designed to carry nukes

The F-117 was built to fight, but the iconic B-2 Stealth Bomber was built to nuke. It was designed to carry up to 16 2,400-pound nuclear bombs deep into guarded Soviet airspace...should the need have ever arisen.

By the time the B-2 underwent its first mission in 1999, though, the Cold War had long ended.

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5 of 18 SSgt Bennie J. Davis III/USAF

The B-2 is flat for a reason

The more vertical surfaces on a plane, the easier it is to spot on a radar screen. That's why the B-2 was designed as flat as possible, without a traditional tail.

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6 of 18 SrA Kenny Holston/USAF

This plane is covered in tiny iron balls

B-2 Stealth Bombers are covered in a substance known as iron ball paint. This coating of microscopic iron spheres resonates with incoming radar waves, absorbing their energy as heat.

The dark paint color, meanwhile, makes the B-2 difficult to spot during its late-night missions.

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7 of 18 Master Sgt. Val Gempis/USAF

The B-2 is maintained in near-pristine condition

The paint job of the B-2 is so important to maintaining stealth that its surface is inspected for chips and scratches after every flight.

"Our pilots' lives depend on how well we do our job. There's no room for mistakes," said Staff Sgt. Jeff Schroeder.

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8 of 18 Airman 1st Class Joel Pfiester/USAF

It's one crazy-expensive aircraft

That level of attention to detail doesn't come cheap, though. Each B-2 Stealth Bomber costs the US roughly $2.13 billion. And that doesn't include the $135,000 it costs per-flight-hour to operate.

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9 of 18 Bobbie Garcia/USAF

The stealthy secret? Triangles

The jagged tail end of the B-2 uses an important design feature called "re-entrant triangles." When radar hits it, the waves are reflected back onto the plane multiple times, lowering the waves' energy.

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10 of 18 Master Sgt. Val Gempis/USAF

Even its exhaust is stealthy

The B-2 must also maintain a low heat signature to avoid detection by infrared.

To this end, the plane's internal fuel tanks act as heat sinks. The B-2 also mixes cool air into its exhaust, lowering its exit temperature.

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11 of 18 Staff Sgt. Madelyn Brown/USAF

This is the USAF's new $1.5 trillion stealth fighter

This is the F-35 Lightning II, the latest generation of stealth fighters. The US is expected to spend over $1.5 trillion(!) to design, purchase and operate 2,457 of these planes through their expected retirement date of 2070.

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12 of 18 SrA Christopher Callaway/USAF

Even the cockpit is built with stealth in mind

The F-35 Lightning II may be largely invisible to radar, but its pilot's helmet isn't. Neither is its instrument panel.

To keep the interior invisible, the cockpit is covered in a thin film of vapor-deposited gold or indium tin dioxide to scatter radar waves away from the receiver.

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13 of 18 Senior Airman Brett Clashman/USAF

This may be the most advanced helmet in the USAF

The F-35 utilizes a helmet-mounted display system that provides pilots with the data they need (for example, speed, altitude, targeting) projected on the helmet's visor.

The helmet also collects data from the plane's six infrared cameras, allowing the pilot to "see through" the plane and view the ground simply by looking between his legs, for example.

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14 of 18 Tom Reynolds/USAF

The F-35's weapons systems are well hidden inside the plane

Exterior mounted missiles are easy to detect on radar, so the F-35 has four hidden weapon bays instead: Two with air-to-air missiles, and two with air-to-surface missiles. It also carries a GAU-22/A cannon (25mm) in its gun pod.

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15 of 18 Alex R. Lloyd/USAF

The new F-35 is pretty terrible at flying

The F-35 Lightning II, years behind schedule and billions over budget, is riddled with problems.

Its software doesn't work right, the ejector seat has the potential to fail, the plane is incredibly difficult to maneuver and fuel inefficient, and its radar system is a mess. Oh, and its fuel tank is unusually susceptible to being struck by lightning.

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16 of 18 Senior Airman Anthony Nelson/USAF

This thing is as hard to spot as a marble

Not all stealth planes are clunky to fly, though. The F-22 Raptor can maintain supersonic flight, and is supermaneuverable.

And it's stealthy as hell. According to the USAF, its radar cross section is equivalent to that of a metal marble.

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17 of 18 MSGT Edward Snyder/USAF

Only one stealth plane has ever been shot down

Stealth planes do have a major weakness: They briefly lose their stealthiness when they open their bomb doors. This fact was a key contributor to the only downing of an F-117 by the enemy, during the 1999 NATO bombing of Yugoslavia.

The pilot ejected from the plane unharmed.

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18 of 18 John Rossino/USAF

The F-22 Raptor is our quarterback in the fight against ISIS

The F-22 Raptor flew its first mission in 2014, when it took out ISIS targets in Syria. It has been described as the "quarterback" plane of the USAF in the theater.

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