From space travel to the World Wide Web, email to nanoscale robots, humanity’s constant drive for improvement and innovation has changed the course of history. So hop aboard and get comfortable — the time machine is all fired up and ready to relive the top scientific discoveries of decades past. Let’s go!
Today we’re heading to the last decade of the 20th century for science that’s hiding in plain sight: stealth technology.
’90s Kids Remember…
Technology in the ’90s wasn’t subtle. While advancements in ’60s microchips, ’70s PCs and ’80s cellular solutions made it possible to reduce overall size and boost processing power, the 1990s harnessed this unparalleled power to create cultural novelties like virtual pet, keychain-sized Tamagotchi, hand-held voice recorders like the TalkBoy and instantly recognizable computer solutions like the gummy-colored 1998 iMacs.
But scientists were also at work behind the scenes streamlining a breakthrough in stealth technology. Let’s break down what it does, why it matters and what comes next for stealth.
Now You See It
In 1887, Heinrich Hertz discovered that when a radio wave encounters an object, some of the wave is reflected back to its source. The nature of the object impacts how much of the wave is reflected and at what strength. For example, radio waves encountering precipitation will create an “echo” that provides general location data, while radio reflections from aircraft or other large objects will provide more precise positioning. Combined with the Doppler effect — which makes it possible to calculate speed based on frequency shifts in waves — radio reflectivity vastly improved human potential for perception.
The military applications were obvious: Radar (radio detection and ranging) became the de facto standard to detect gunfire, locate ships and find potentially hostile aircraft. It also fueled a new branch of scientific theory: stealth technology.
Now You Don’t
With radar stations broadcasting radio waves around the globe, military minds faced a challenge: How could they make planes disappear?
Broadly speaking there are two stealth solutions: absorption and deflection. Absorption requires planes to be coated in radio-converting materials that translate electromagnetic energy to heat, or by using pyramid-like structures that capture waves and dissipate their energy by causing successive contained reflections.
Deflection is — in theory — less complicated and more effective. Here, plane shapes are altered so radar pulses are deflected away from the receiver station, making it appear that there’s nothing in the sky when in fact a stealth bomber or fighter jet is sailing overhead.
Tacitly Tactical
In 1975, the Defense Advanced Research Projects Agency (DARPA) began tapping private companies for new ways to improve stealth technology. Why? Because despite the name, no aircraft is truly “invisible” — with the right radar setup and the right operators, even well-engineered craft can be detected. The goal is to achieve “low observability” by reducing the number of aligned aircraft edges and creating shapes that allow radar to effectively slide off airplane surfaces instead of being reflected.
Northrop Grumman’s Tacit Blue craft leveraged new advancements in computing and processing to create smoothly flowing, complex curvature surfaces that were elegant, aerodynamic and more effective at deflecting radar than their predecessors. While Tacit Blue never engaged in active military service, its research advancements paved the way for the rapid development of stealth technology in the ’90s including the F-117A Nighthawk and the B-2 bomber. As noted by Business Insider, even 30 years later the B-2 remains one of the world’s most formidable military achievements.
The Future of Sight Unseen
So what’s next for stealth technology? As noted by The Drive, “morphing wings” offer the potential to change airplane shape on-demand by seamlessly integrating flaps and joints into wings and virtually eliminating any visible control surfaces.
Also in development? “Quantum radar” technologies designed to unmask stealth planes by leveraging the concept of quantum entanglement. Radar-absorbing nanomaterials may provide the scientific counterargument to quantum detection, but aren’t yet viable at scale.
Simply put? Commercial technology in the ’90s focused on the frivolous but just out of sight. Great strides were being made in stealth solutions. As detection and reflection tools continue to evolve, it’s a safe bet that this under-the-radar research still has decades of development to deliver.
Up next? We crash Y2K and march into the new millennium. Join us as we take on the 21st century.
