TL;DR
Three companies — Boom Supersonic, Astro Mechanica and Hermeus — are pursuing new engines, airframes and business models to revive affordable supersonic travel. Recent technical demonstrations and a U.S. regulatory change have removed some major barriers, but commercial service still faces years of testing and certification.
What happened
The author visited Boom Supersonic and Astro Mechanica and interviewed the founder of Hermeus to survey recent progress toward a renewed era of supersonic passenger flight. Boom’s one-third-scale XB-1 demonstrator became the first privately developed jet to exceed Mach 1 while using “Mach cutoff” and AI to keep the sonic boom from being heard on the ground. That demonstration coincided with a U.S. executive order (14304) permitting supersonic flights over land provided they do not produce an audible boom. Boom is developing a full-scale airliner called Overture and its own non-afterburning turbofan, Symphony, and has recorded 130 orders; the company projects first test flights in about three years. Astro Mechanica is pursuing a turboelectric adaptive engine that shifts modes between efficient subsonic operation and ramjet-like performance for supersonic flight, and has progressed through three rapid engine generations. Hermeus was included among the innovators but specific developments from that company are not detailed in the source.
Why it matters
- Reduced travel times could reshape long-haul routes and business travel economics.
- A regulatory change in the U.S. opens the possibility of supersonic flights over land if sonic booms are inaudible.
- New engine designs aim to address Concorde-era fuel inefficiency, lowering operating costs and ticket prices.
- Different business models — selling jets to airlines versus operating on-demand small supersonic services — could broaden access.
Key facts
- Boom’s XB-1 was the first privately developed jet to break the sound barrier and did so without an audible ground-level sonic boom.
- Boom used a concept called 'Mach cutoff' and AI to shape flight profiles so sonic booms dissipate upward.
- On June 6, an executive order (14304) restored the right to fly supersonic over U.S. land provided the aircraft do not produce an audible sonic boom on the ground.
- Boom is developing Overture, a Mach 1.7 airliner, and an in-house non-afterburning turbofan engine called Symphony; Symphony is designed specifically for cruise at Mach 1.7.
- A fully assembled Symphony engine is reported to weigh about 14,000 pounds; individual nickel-alloy components seen at Boom weighed hundreds of pounds.
- Boom has recorded about 130 orders for its Overture aircraft.
- The author estimates first Overture test flights in roughly three years and FAA certification requiring extensive flight hours over about two years, with commercial service plausibly around 2033.
- Astro Mechanica is developing a turboelectric adaptive engine that shifts between turbofan, ramjet and rocket-like modes and has completed three rapid engine generations (Gen 1–3), with Gen 3 in hot-fire testing.
- Astro emphasizes using liquefied natural gas (LNG) as a fuel; the source states LNG burns about 30% less CO2 than kerosene, offers about 60% more range, and is roughly 10 times cheaper than kerosene.
What to watch next
- Boom’s timeline for Overture: first test flight in about three years and subsequent FAA certification testing over roughly two years.
- Progress and results from Astro Mechanica’s Gen 3 hot-fire engine tests and further demonstrations of its turboelectric adaptive concept.
- Adoption and operational plans: whether Boom’s sales model to airlines or Astro’s on-demand, small-aircraft service model gains traction.
- Hermeus developments: not confirmed in the source
Quick glossary
- Sonic boom: A loud sound associated with shock waves created when an object travels through the air faster than the speed of sound.
- Mach cutoff: A flight technique and aerodynamic concept that uses altitude and atmospheric conditions to direct sonic boom energy upward so it does not reach the ground audibly.
- Turbofan: A type of jet engine that uses a fan to generate thrust and is commonly used on commercial airliners for efficient subsonic cruise.
- Ramjet: An airbreathing jet engine that relies on high forward speed to compress incoming air, useful at supersonic speeds but inefficient at low speeds.
- Liquefied natural gas (LNG): Natural gas cooled to a liquid state for transport; it has a higher energy-per-mass density than gaseous fuel and different combustion characteristics than aviation kerosene.
Reader FAQ
When might passengers fly supersonic again?
The author estimates commercial flights on Boom’s Overture could arrive around 2033, after test flights and FAA certification.
Are supersonic flights allowed over U.S. land now?
An executive order (14304) permits supersonic flight over land provided the aircraft do not produce an audible sonic boom on the ground.
Will supersonic travel be as expensive as Concorde was?
Boom projects a NYC–London round-trip could cost about $5,000; Astro aims for prices under $1,000 on some point-to-point routes, per the source.
Has the noise problem been solved?
Boom demonstrated an XB-1 flight that exceeded Mach 1 without an audible boom on the ground using Mach cutoff; broader noise performance will depend on certification and operational practice.
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Sources
- Dude, where's my supersonic jet?
- SFO to Tokyo in 6 hours? Startup breaks the sound barrier
- Where's the Second Supersonic Age We Were Promised?
- Boom's Quest to Make Supersonic Flights a Reality (Again)
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