[Music]
imagine traveling from New York to
London in just a couple of hours or
waking up in California and flying to
China in time for lunch hypersonic
flight could advance travel in ways we
haven't seen since the invention of
flight itself but flying at hypersonic
speed isn't easy
it presents incredible engineering and
logistical challenges so how close are
we
hypersonic travel before we get the
hypersonic speed we should probably
really talk about supersonic speed
basically supersonic speed is when
you're traveling faster than the speed
of sound which is something we can and
frequently do certain military airplanes
will fly above Mach 1 and the concorde
commercial plane famously flew at
supersonic speeds from 1976 to 2003
supersonic speed is really really fast
but hypersonic speed is in a league of
its own so hypersonic means typically
velocities above Mach 5 or equivalently
velocities above 3,800 miles per hour
now going at least five times faster
than the speed of sound may seem crazy
but it's actually a milestone we've
reached multiple times in the past from
the general public's perspective
probably the most visible example of
hypersonic flight is watching a space
shuttle reenter the atmosphere now okay
sure the space shuttle reaches
hypersonic speed just by falling back to
earth but in the 1960s NASA did achieve
manned hypersonic travel through actual
propulsion with an x-15 jet setting a
speed record that Wow unofficial has yet
to be broken and there's pretty good
reason for that the effects of flying
hypersonically in the atmosphere are
catastrophic for the airplanes now we
know parts of the
fuselage they would actually chart right
you were met because the studio of the
aircraft was getting consumed this is
where the problem with long-duration
hypersonic travel starts when you're
traveling below the speed of sound the
temperature around the aircraft stay as
close to the ambient temperature but
once you break the sound barrier a shock
wave is created and the gas molecules
behind the shock wave become compressed
this makes the air around the plane hot
like really really hot near hypersonic
speeds it's so hot that it can damage
the materials that make up the body of
the airplane now traditional airplanes
are made of aluminum alloys that have a
melting temperature of about 600 degrees
Celsius an advanced aircraft will have
titanium bodies with even higher melting
points but the air around an aircraft
flying at Mach 10 can reach 3,000
degrees Celsius so how did vehicles like
the Space Shuttle
not burn up completely when they reenter
the atmosphere at hypersonic speeds
historically what we've done is we just
put on the heat shield that's five six
eight ten times heavier than it needs to
be and thicker than it needs to be
because you can never be too careful
you want your your people or your
payload to get back in one piece but
those heat shields typically burn off
completely during reentry and reapplying
a heat shield for every single flight
wouldn't exactly be practical or
possible for hypersonic commercial
travel different materials are needed to
withstand these extreme temperatures and
researchers are exploring all kinds of
options from tantalum carbide to boron
nitride nanotubes
if hypersonic speed does this kind of
damage to planes what about the people
inside fortunately traveling at
hypersonic speeds isn't harmful as long
as it's constant rapid acceleration or a
sudden change in direction is another
story so some simple money overs that
can be done with our liners if you were
to do the same turn and Mach 10 the
accelerations that we'll be generating
with the cabin
for the passengers will be about 40 G's
right 40 times the gravitational
acceleration which will basically kill
everybody on board
another potential concern could be
increased radiation from flying at
higher altitudes which a hypersonic jet
would need to do there's also the issue
of losing cabin pressure while traveling
that high up in the stratosphere but
flying commercially already comes with
similar risks that airlines prepare for
of course none of these problems really
matter if we aren't able to reach speeds
of Mach 5 and above in the first place
just because we've done it before
doesn't mean it's easy to replicate
historically we have just strapped
people to a rocket and fired him into
space but if you wanted to fly from New
York to Los Angeles on a hypothetical
hypersonic airliner a rocket is not a
very efficient way to do things one idea
is to use something called a supersonic
combustion ramjet or scramjet a rocket
has to carry the liquid oxygen it needs
for combustion making it incredibly
heavy and not efficient for commercial
travel a scramjet on the other hand is
able to use oxygen from the atmosphere
to create combustion even at hypersonic
speeds but the scramjet is still a work
in progress in 2015 Boeing's scramjet
equipped x51 flew at Mach 5.1 but only
for about three and a half minutes it
was also unmanned and was launched from
an aircraft already in flight which
isn't exactly what we have in mind for a
long duration hypersonic flight despite
this there is real progress being made
in hypersonic engineering just in a
different kind of setting so if you
think about like a cruise missile flying
at five times the speed of sound that's
incredibly hard to stop and so that's
what's driving a lot of the interest in
the topic right now both China and
Russia have claimed to have tested
hypersonic weapon systems and the u.s.
is currently trying to catch up and this
wouldn't be the first time hypersonic
research started in military
applications it was after the war -
during the development of
intercontinental ballistic missiles
during the Eisenhower administration
that there was a lot of research done in
hypersonics most of the fundamental
concepts that we know today are derived
from those things
Boeing is one company that's hoping to
make the jump from military applications
to commercial flight its concept for a
hypersonic airliner comes after working
with DARPA on a hypersonic space plane
and working on the scramjet powered x51
with the airforce Boeing plans for this
potential airliner to be able to travel
at Mach 5 reducing your transpacific
commute to a measly two hours I mean we
doesn't want to travel from New York to
Los Angeles in 15 minutes right you know
every time the airlines make my seat
narrower and make me have lesser legroom
I wish even harder that we were flying
at Mach 5 and I could get to where I'm
going in 15 minutes and only have to be
stuck in the cattle car for that long
and that's the potential of hypersonic
speed the ability to connect to anywhere
in the world in that amount of time
would be an incredible achievement it's
also critical to study as we plan to
explore places like Mars because
entering that planet's atmosphere would
be done at hypersonic speed the public
imagination or perspective and the
desire to have successful space missions
we need to do a good job of and working
through these technologies and these
research problems it's their dynamics
its material science its computer
science for controls and electrical
engineering it's all of these things
that it's all a group that plays into
this bigger hole I see hypersonic travel
similar to what prehistoric fish did 300
million years ago when they left water
and they began the life on land
so the conquest of air and space is also
fundamental step in the evolution of
humankind similar to LACMA
the next step in connecting our little
blue planet and eventually exploring
planets outside of it might be
conquering hypersonic speed so how close
are we to hypersonic travel I think
sustained hypersonic flight in
military since you know in the form of
say an unmanned missile or something you
might see that in the next three four or
five years I mean I think that would be
a pretty quick turnaround on that as
long as the funding keeps up so I
believe that with the correct level of
funding and with the enthusiasm of a
population it will not be difficult to
put two-person group for instance in an
aircraft and fly beyond the mark six
point seven I was active in next 15
within the next ten years that dream of
commuting around the world in a few
hours though for now you'll still have
to deal with a long red-eye
intercontinental flight thanks for
watching how close are we and let us
know in the comments what topics you
want us to cover in future episodes if
you want more help those are we click
here to watch our playlist and don't
forget to Like share and subscribe