Updated August 13, 2021
Potential Military Roles for Supersonic Transports
A new generation of supersonic (faster than the speed of
Figure 1. Boom Overture
sound in level flight, also called Mach 1) passenger aircraft
Artist’s Rendering
is now under development. Using “low-boom” technology
developed through NASA research to minimize sound
signatures on the ground, advanced engines, and alternative
fuel concepts, these new supersonic transports (SSTs)
advertise the ability to fly over populated areas with
minimal disruption, cruise more economically, and avoid
some of the potential negative environmental effects of
carbon-based fuels in high-altitude flight.
These new aircraft have attracted interest and some
Source: Boom Supersonic.
investment from the U.S. military, and have on occasion
Boom was founded and is run by Blake Scholl, a former
been proposed for military missions by their developers.
software engineer. It has raised backing primarily from
The potential roles differ with the size and capabilities of
Silicon Valley venture funds and is partnering with Rolls -
each aircraft.
Royce to develop engine concepts.
History
Exosonic
Aircraft first went supersonic in 1947. Since then, two
supersonic transport aircraft (SSTs) served in commercial
Exosonic, of Los Angeles, is designing a 70-passenger,
Mach 1.8 low-boom airliner with a 5,700-mile range. CEO
airlines. The Soviet Tupolev Tu-144 flew from 1968 to
Norris Tie comes from the aerospace engineering world.
1999, although it was only in commercial service (with
The company has yet to announce a timeline for its aircraft,
Aeroflot) for three years. The Anglo-French Concorde flew
from 1969 to 2003, most of that time in service with British
although a subscale demonstrator is reportedly slated for
Airways and Air France.
2025.
Figure 2. Exosonic Airliner
Due to the technology of their time, those SSTs were
hampered by high operational costs (particularly for fuel)
Artist’s Rendering
and operational restrictions resulting from many countries’
prohibitions against sonic booms over land. (A sonic boom
results when the shock wave created by a supersonic
aircraft touches the ground, and is heard as a sharp, loud
report resembling an explosion.) These restrictions
relegated earlier SSTs to trans-oceanic service, excluding
them from a number of potentially profitable routes.
Current Principal Developers
Source: Exosonic.
Two companies are leading the development of new SSTs ,
with a few others newer to the field, and one previous
Aerion
leader having now shut down. The three main firms are at
Although having led in development of a new-generation
different stages in the process, and targeting somewhat
low-boom SST, Aerion, of Melbourne, FL, ceased
different markets.
operations in May 2021, having completed wind tunnel
Boom Supersonic
tests of its AS2, intended as an 8- to 10-passenger business
jet with a 5,400-mile range at a top speed of Mach 1.4. The
Denver-based Boom is developing the Overture, a 65- to
three-engine jet was anticipated to enter service in 2027 at a
88-passenger airliner designed for Mach 2.2 with a range of
target price of $120 million. The company was founded by
5,100 miles. The company expects to fly a one-third-scale
entrepreneur Robert Bass and was run by Tom Vice,
demonstrator this year. Projected to enter service in 2029,
formerly head of Northrop Grumman Aeronautics. Boeing
the Overture is targeted to cost $200 million for the basic
held a stake in the company, and General Electric had been
aircraft.
designing the AS2’s engines.
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Potential Military Roles for Supersonic Transports
Figure 3. Aerion AS2
Continuity of Operations/Continuity
Artist’s Rendering
of Government
Rapid relocation of national leaders in time of crisis could
enable their presence at command posts and reduce the
impact of interrupted or degraded communications
networks.
Special Operations
Deploying small teams to trouble spots quickly for missions
like hostage rescue or embassy defense has been cited as a
role where increased speed can be decisive. (It is less clear
how such a deployment could be kept covert if the teams
are using an aircraft not in common service around the
Source: Aerion.
world.)
Organizations at earlier stages of development include
Nuclear Security
Virgin Galactic, a private space company, which has
Using high-speed aircraft to transport warheads for nuclear
teamed with Rolls-Royce to study a 9- to 19-passenger,
weapons to forward units could allow those warheads to be
Mach 3 jet;
stored in the United States with high security, then sent
forward only when they might be needed—or when
Boston-based Spike Aerospace, which is proposing a
national commanders wanted to send a signal of possible
12- to 18-passenger low-boom aircraft aimed at Mach
consequences to an aggressor and/or reassure allies.
1.6;
Intelligence, Surveil ance, and Reconnaissance
Hermeus, of Atlanta, which proposes a Mach 5, or
hypersonic, aircraft. Its capacity and schedule are not
Adaptation of a supersonic platform that flies at very high
altitude could give U.S. forces highly responsive, easily
yet announced. However, on August 5, 2021, the U.S.
redirected intelligence platforms of a sort absent from the
Air Force, in cooperation with some private venture
capital firms, announced a three-year, $60 million
inventory since the retirement of the SR-71.
contract with Hermeus to further advance its
Humanitarian Relief
development.
In a number of scenarios, rapid dispatch of relief supplies,
Possible Military Uses
medical teams, and/or other specialists to areas suffering
The U.S. military already has supersonic fighters and
from natural disasters, virus outbreaks, or other events
bombers. Some other military missions could potentially
could make a positive difference in outcomes.
benefit from higher-speed travel for people and/or small
Rapid Reinforcement
loads of cargo, including but not limited to the following:
Moving additional troops to areas under siege or suffering
Executive Transport
from surprise attack could enhance commanders’ options
and allow the United States to multiply force on short
In September, 2020, the Air Force Research Lab awarded
contracts to Boom (reportedly $2 million) and Exosonic ($1
notice at times and places of its choosing.
million) to explore the use of their aircraft for executive
Medical Evacuation
transport. This followed an earlier $1.5 million contract
Moving wounded personnel to high-level care facilities in
with Hermeus for the same purpose.
roughly half the time of current airlifters could significantly
The Air Force executive transport fleet currently includes a
increase the chances of survival.
wide range of aircraft used for moving senior commanders,
Crew Replacement
congressional delegations, and government officials ,
including the President. Those aircraft are derivatives of
Dispatching relief crews for ships or submarines stricken by
existing commercial airliners and business jets.
illness could minimize downtime and restore U.S. sea
presence in vital areas.
Adding speed to personnel transport offers several potential
benefits. Getting senior diplomats to meetings in times of
A basic configuration could allow a number of these
crisis could help defuse tensions. Moving senior officials to
missions to be carried out by the same aircraft. Having to
reconfigure the aircraft for specialized missions could
remote meetings or site visits in ways that minimize time
reduce the time advantage a supersonic aircraft would have
away from their principal duty station could allow them to
over those currently in the fleet.
work more efficiently.
Jeremiah Gertler, Specialist in Military Aviation
IF11778
https://crsreports.congress.gov
Potential Military Roles for Supersonic Transports
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