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Comment by melling | Hacker News Reader

Any peace dividend for the research?

Are we a step closer to hypersonic commercial flight?

Worth considering that nearly all of these hypersonic weapons rely on a pretty beefy booster to get the initial altitude and energy. I don't know what the range/time range off between these hypersonic solutions versus a pure ballistic solution would be. In a military context, these hypersonics grant a variety of interesting capabilities, all of which seem relatively irrelevant to civilian applications.

Or rather, back to it.https://en.wikipedia.org/wiki/Concorde

> First, let's establish some terms. Hypersonic is, obviously, supersonic on steroids. But while "supersonic" has the clear cut definition of being faster than the speed of sound (Mach 1), hypersonic is a little fuzzier. Generally, hypersonic speeds are the point at which the molecules of air that surround the aircraft start to change by breaking apart (dissociation) and/or picking up electrical charge (ionization). These things don't happen at one particular speed, so the term "hypersonic" instead refers to the point at which they start to meaningfully affect the mechanics of flight—generally accepted to be Mach 5, or 3,836.35 mph in conditions of 20 degrees Celsius at sea level.

Source: https://www.popularmechanics.com/flight/a28426/hypersonic-sp...

At Mach 2, Concorde was supersonic, not hypersonic

Yes, but we're worst from that now, for commercial flights.

From supersonic back to subsonic...

Concorde was a loss-making government-subsidized program, and you can always make things "advance" by burning money. Although on occasional years it was (barely) operationally profitable, it never made a profit once depreciation of assets was considered, much less the cost of the development program. Given the available technology and society's decision to ban sonic booms over populated areas, this (we know now) was inevitable.

It's worse than that. In order to conserve fuel, most commercial jets fly slower than they used to.

I hear that often, but it seems this doesn't apply to the flights between Asia and France which go over my town.

I know this because when i'm awake in the night i can hear them trough double paned glass in closed windows and then click on flightradar24.com to see who it is.

And then see them between 10.5km to 11.5km up, with speeds between 950 and 1050 kph above ground. Airbus 380 or Boeing 777-ER usually.

This goes both ways between Paris/CDG and many large locations in Asia, easily a dozen per night and direction.

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