From a Wright Brothers first flight spanning just 120 feet to breaking the sound barrier to nearing the edge of space, aviation history has trailblazed tremendous progress in little over a century. We went from Mach 0 to Mach 1, and now setting sights on Mach 5. This brings us to the central question…
What sets hypersonic and supersonic aircraft apart, where could they take us, and how close are we to getting there?
As an aviation geek, I decided to crunch the numbers and uncover the realities, ambitions, and possibilities of ultra-fast travel. Let’s compare some key metrics and peer into the future!
Defining High-Speed Flight
First, what do these terms mean?
Supersonic refers to speed faster than the 767 mph (1,235 km/h) speed of sound at sea level, also known as Mach 1. Supersonic aircraft exceed Mach 1 but remain under Mach 5, or about 3,800 mph at sea level.
Hypersonic velocity begins where supersonic ends – at Mach 5 and beyond, which equates to speeds over 3,800 mph up to astonishing figures like Mach 25!
Even as you read this, aerospace engineers around the globe are working feverishly to understand, harness, control and optimize travel at these blistering speeds using advanced engines, materials science and design principles at the bleeding edge.
Key Milestones: Breaking the Sound Barriers
Let’s reflect on some of the first daring attempts to surpass Mach limits:
Supersonic
- 1947 – Capt. Chuck Yeager piloted the rocket-powered Bell X-1 past Mach 1, heralding the age of supersonic flight
- 1976 – The Concorde airliner enters service, crossing the Atlantic in under 3.5 hours with seating for 92-128 passengers
- 2021 – Boom Supersonic rolls out XB-1, a 1/3 scale prototype of its upcoming Overture commercial supersonic jet
Hypersonic
- 1998 – NASA‘s X-43A hit Mach 7 (5,300 mph)
- 2010 – The U.S. Air Force‘s X-51A WaveRider reached Mach 5 (3,900 mph)
- 2020 – China claims successful flight test of a reusable spacecraft capable of Mach 6
As you can see, supersonic flight became viable decades ago while routine hypersonic flight remains an ambitious goal. But the pace of progress is accelerating as entities like DARPA, SpaceX and Boeing ramp up research.
Next, let’s do a head-to-head comparison across some key metrics.
Hypersonic vs. Supersonic In Numbers
| Characteristic | Hypersonic | Supersonic |
|---|---|---|
| Typical Speed Range | Mach 5 – 25 | Mach 1 – 5 |
| Speed in MPH | 3,800+ mph | 767 – 3,800 mph |
| Example Aircraft | USAF X-51 (Mach 5) | Concorde (Mach 2) |
| Engine Types | Scramjets, ramjets | Turbofans |
| Altitude | Up to 50,000 feet | Up to 60,000 feet |
| Current Applications | Experimental & military | Mostly military |
| Sonic Boom Impact | Minimal | Significant |
As the stats show, hypersonic aircraft start where supersonic tops out in terms of speed. They also cruise at higher attitudes. Interestingly, their high-altitude hypersonic booms dissipate before hitting the ground, reducing noise pollution.
Now that we’ve seen some figures, let’s digest the history…
Supersonic Timeline – Fast, Faster, Too Costly
The supersonic Concorde cruised at Mach 2.0 as one of humanity’s aviation marvels back in 1976. But this turbojet-powered giant consumed a gigantic amount of fuel. Prone to fluctuations in oil prices and global events, operating Concorde profitably proved an uphill battle.
After a horrific 2000 crash, orders dried up. By 2003, Concorde flew its last flight into retirement after just 27 years pressurized by high maintenance bills.
However, smaller startups aim to succeed where Concorde failed. Boom Supersonic aspires to activate history’s first commercial supersonic travel in 2029 with its Mach 2.2 Overture jet. Advances in engines and lightweight composites could make this 75-seater aircraft cost-effective at $100 million per copy.
Make no mistake, Boom and contemporaries have their work cut out to make supersonic economically viable once again. From sonic boom concerns to high fuel usage, environment regulations, and infrastructure requirements, the barriers persist as generations of engineers can attest.
The Hypersonic Frontier Still in Flux
Now to the bleeding-edge. Hypersonic flight remains entrenched in experimentation with control, reliability, and real-world operating challenges aplenty. Materials able withstand blistering temperatures for prolonged durations stay elusive. Runway needs for safe takeoff and landing remain unspecified. Traditional turbo-machinery won’t cut it propulsion-wise past Mach 5, demanding new systems like:
-
Scramjets: Only operate efficiently at hypersonic velocities, allowing air to flow supersonically throughout the engine
-
Ramjets: Rely on high aircraft speed to compress inflowing air with no mechanical compression needed
Plus, potential militarization of hypersonic missiles elicits anxiety. All reasons why mastering hypersonic speed sits on technology’s greatest frontier.
Yet, the allure persists.
DARPA’s partnerships with companies like Boston-based Reaction Engines hover around Mach 5 aspirations. Their synergetic engine cycles between turbojet and ramjet configurations from take-off to soaring hypersonic with the best of both worlds.
CAFE Foundation’s efforts with Boom focus on catalytic engine solutions for sustainable hypersonic flight.
Orbital altitude providers like Virgin Galactic convey optimism for commercial space access.
Clearly, boundaries still require some bending before crossing this Rubicon.
Government aviation agencies project we’ll crack open economically feasible hypersonic travel in the 2040s-2050s timeframe. But assuming steady progress in testing, hypersonic flight could necessitate infrastructure and economic changes on a scale rivaling mainstream air travel itself.
Yet for risk-takers with deep enough pockets like NASA, SpaceX or Blue Origin, expectations remain markedly ambitious. The next decades will prove telling!
For now, supersonic flight revival seems closest as the next attainable hop. As engineers further that work, iterating in computer models and test chambers, the hypersonic future remains in the distance but not beyond theoretical reach.
Social & Environmental Considerations
Transportation breakthroughs require diligence to assess and mitigate unintended consequences. As seen from Concorde’s retirement and growing climate change awareness, society won‘t accept technical achievements blindly.
Sonic booms worry environmental groups and policy makers. Fuel usage and emissions need sharpening before expansion. Noise pollution near airports and waste byproducts demand consideration too.
Industry leaders acknowledge these factors during development, but benefit from maintaining open communication channels with citizens regarding testing timelines, progress and impact.
On the flip side, skeptical citizens have proven receptive to measured introduction when positive business and social use-cases come forward.
Striking the right balance remains key.
The Future of Flight Beyond Mach
Engineers pursue hypersonic heights as the new Everest. In exploring these altitudes and possibilities, arising technologies could reshape aviation but also transform space exploration. The passion persists in the community which makes me optimistic.
Perhaps one day, routine access to suborbital or orbital space becomes commonplace thanks to hypersonic opening this door. Maybe continents connect faster than ever envisioned. Or, micro-satellites deploy in minutes versus months.
Are outposts on the Moon or Mars easier to construct? Do emerging economies access congested hubs instantly? Can last-mile critical payloads like organs or medicines reach remote regions in time to save lives?
The promise resides in the problems these velocities could ameliorate if harnessed appropriately. But significant hurtles remain at present.
Rest assured, the brightest minds stay fixed on provocative questions of if, how and when we tame hypersonic flight for societal good. Momentum and investments continue rising to manifest answers over the coming decades.
Personally, I can’t wait to someday chronicle the next history-making Mach number smashed as we charge further past sound and imagination at lengths thought infeasible. What a time to be alive during this age of aviation wonders!
Let’s fasten our seatbelts and find out together where it takes us.
