Boom Supersonic wants to rejuvenate intercontinental travel

Is the aviation sector ready for another supersonic age?

Image credit: Boom Supersonic

Nearly two decades since Concorde retired, the world is edging closer to again having passenger jets that can fly faster than the speed of sound. Beyond safety issues, Concorde was expensive and environmentally damaging – a new aircraft needs to overcome these major obstacles.

Somewhere between starting fires and flinging electric cars into space, human beings became disconnected from technology. Progress, long contingent on people doing things, was pushed across some invisible psychic line to become its own force.

Moore’s Law is not an industry insider’s term – it’s a capitalist philosophy. Every year, tech brands release shinier, newer, and nebulously ‘better’ versions of the dusty, scuffed and concretely ‘worse’ things we bought last year, because this is what technology does.

When it doesn’t – if, say, a global pandemic were to hobble the production of a new games console – the professionally furious will skitter out from the craterous hellscape of social media to shriek at technology until it can once again keep pace with their entitlement. Come war, come pestilence, come famine or plague, the engines must be stoked, the line must be kept clear, the train must never slow down.

This makes supersonic flight a singular anomaly. In the 1950s, teams of British and French engineers met to build an aircraft that would, from the 1970s to early 2000s, ferry around 100 passengers at a time back and forth across the world at over twice the speed of sound. For 30 years, if you wanted to cross the Atlantic in three hours, you could. And now, 20 years later, you can’t.

That might be about to change. Aviation start-up companies like Boom Supersonic are pursuing, for the moment, what they believe to be a lucrative market in supersonic business jets (Boom’s first planned commercial airliner, the ‘Overture’, which will seat between 65 and 88 passengers, cruises at around 60,000ft, flies at Mach 1.7 with a range of around 5,000 miles, and is already on order from US carrier United Airlines). While the coronavirus pandemic has helped sink at least one other big start-up (Aerion Supersonic and its diminutive private jet, the AS2), Virgin Galactic announced in late 2020 that it too would be turning its engineering talent at least partially away from spacecraft and towards its own supersonic transport (SST) that will fly at Mach 3 – or one-and-a-half times as fast as Concorde.

Each would-be SST developer is at pains to highlight new technologies that will ensure their aircraft avoid the two major criticisms of the Concorde: that while it was a technological marvel, it was also prohibitively expensive to fly and – even at the time – a wonderful target for environmentalists looking for something to stick on placards.

Across all their interviews and PR materials, SST companies eagerly explain how affordable their flights will be (‘affordable’ in the context of supersonic business travel actually means ‘about $5,000 (£3,500) one way’). As for the environmental impact of tens of thousands of very rich people zipping around so affordably, SST manufacturers have promised everything from new synthetic aviation fuels to carbon capture to fuselages that are completely recyclable. None of the companies as yet claim to weave their planes from hemp – but you get the distinct feeling that it’s only a matter of time.

However cheap and green the next generation of SSTs turns out to be, whether they will emerge as the heralds of a second supersonic age is far from clear (as their creators and cheerleaders insist they will be: Boom CEO Blake Scholl dreams of a future in which one can fly anywhere on the planet in under four hours for $100 (£70) – a goal on which the company’s press office would not expand).

Former British Airways pilot Captain John Hutchinson, who flew Concordes for 15 years, sees one important differentiator between the production of the Concorde and that of the new SSTs. “Concorde itself was so far ahead of its time, I would rank it on the same level as the lunar landing,” he says. “It was in many ways the European equivalent... [It] was a project that involved national pride. The nation accepted and rose to that challenge and achieved something that did exactly what it said on the tin. And I think the country has always had this passion for that aeroplane – a passion that still exists today.”

That passion is something that, unfortunately for builders of next-generation SSTs, cannot obviously be bought. Concorde’s origin story is one not only of international cooperation between two great engineering nations, but also of competition between those two European nations and the Soviet Union. We got Concorde (“absolute perfection; a fusion of pure art and technology into one sublime whole”, Hutchinson says) and the Soviets, with their rival Tupolev Tu-144 ‘Concordeski’, got an airborne collection of mechanical faults hammered together into the shape of an aeroplane. That’s a better story than “we saw an opportunity to take five grand a pop off impatient business people, so we built this”.

If supersonic flight becomes cheap enough, perhaps slightly dull origin stories won’t matter. It’s worth remembering that Concorde had no competitors for its entire 30-year lifespan. British Airways ticket prices, as Hutchinson recalls, were at one point set after polling the aircraft’s regulars on what they thought their tickets had cost and then inflating the prices – with a pressure hose – to match. With competing designs and operators, market forces might plausibly drive prices down, making supersonic flight less glamorous, but more commonplace.

Except here the new SST manufacturers bump up against another challenge that Concorde was never able to overcome: the sonic boom.

“The sonic boom was not something that was easy to quantify,” says Hutchinson, who spent the better part of 15 years inside one. “The intensity of that boom depends on all sorts of different variables: the structure of the upper atmosphere on a particular day, the temperature gradients, the jetstream, the weight and size of the aeroplane... There are all sorts of variables [which] became more understood as experience with the aeroplane was gained – but there has never been a solution to that sonic boom.”

At least, not an engineering solution. A legislative solution has been in place since the early days of Concorde: practically speaking, you cannot fly a supersonic civilian aircraft over land. Without an engineering solution – in lay terms: a way to fly at supersonic speeds without blowing out the nation’s windows and deafening the citizenry – new SSTs will be restricted to trans-oceanic crossings, severely limiting their areas of operations. Supersonic aircraft can of course fly over land at subsonic speeds, in the same way you could use a Lamborghini to move house: it’s doable, but why?

Going fast will never not be a thing that people will pay money for. Going as fast as possible will never not be a thing that draws engineering minds away from the practical and into areas where things that go wrong do so in fireballs. But the previous supersonic age didn’t end because the technology was unreliable, unsafe, or unpopular. It ended because the industry saw the same limiting factors for supersonic flight as exist today. The questions of affordability and accessibility that were first asked more than half a century ago have still not been answered.

Concorde weathered these restrictions for 30 years because it inspired wonder, pride, and reverence. Business jets don’t do that – no matter how fast or recyclable they may be.

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