spacex recently launched their crew 1
mission to the international space
station using the iconic merlin engine
but now spacex has developed an entirely
new raptor engine to realize an even
further goal
mars and it starts with a new kind of
fuel that's not only less dense
but also more efficient and eco-friendly
so how does this new fuel
compare to ones used in the past and
what does it mean for sending humans to
other planets
in terms of the mixture needed to launch
a rocket we need two things
a fuel or what's also known as a
propellant and
an oxidizer to release oxygen in 1926
legendary engineer dr robert goddard
used a combination of gasoline and
liquid oxygen to launch the very first
rocket
it was a great starting point but as
better mixtures were developed
gasoline really lost its popularity
because when considering the safety of a
crew
it's just an all-around bad idea to have
an extremely volatile substance
as your main propeller now let's jump to
1981
when manned space shuttles started using
liquid hydrogen
to power their acceleration into orbit
in combination with an oxidizer like
liquid oxygen
you got the fuel that launched over 130
shuttles
when burned this combination actually
yields the highest specific impulse
of any known rocket fuel specific
impulse is a measure of how effectively
the energy content within the propellant
actually is converted into thrust
so we can basically think of this as a
rocket's fuel economy
similar to what you find with your car
shopping knowing the efficiency of the
propellant
actually helps us to calculate just how
far we can go but a major drawback of
using liquid hydrogen
is its density with a relatively low
density of only 70 grams per liter
this requires engineers to use much
bigger fuel tanks than they would use
for higher density fuels
like kerosene which was the fuel that
brought astronauts to the moon back in
the apollo era
so having a propellant with a higher
density means a smaller fuel tank
a lighter rocket and the ability to go
further distances
fast forward another 20 years to the
2000s where russia's rd-180 engine
and the spacex merlin engine utilize a
combination of rp1
and liquid oxygen nrp1 is really just a
highly refined form of kerosene
this is mainly used for its incredibly
high density of about 806 grams per
liter
making rp-1 the ideal fuel to pack as
much power as possible
into a smaller fuel tank and with a
boiling point of over 420 degrees kelvin
it's also really good at withstanding
heat increases that you see during
launch
a higher boiling point also means less
installation is needed for the fuel tank
which means more space for your fuel and
a lighter rocket
but rp-1 has some drawbacks that are
leading spacex scientists to look at a
different propellant which could be used
specifically for mars exploration
enter the spacex raptor engine and its
next generation propeller
this engine uses a combination of liquid
methane and liquid oxygen to create
what is in my opinion the perfect
mixture for a reusable vehicle on mars
not only is this an efficient fuel but
it can easily be created using resources
that we can find on the red planet and
this is great because one of spacex's
main goals is to create a system
that can take humans to mars and back
both methane and co2 could be extracted
from the atmosphere
using solar power and water could be
mined near the surface of mars
using whales and when compared to rp1
methane not only has a higher specific
impulse and the cooler combustion
temperature
but it also prevents coking which is the
buildup of deposits in the engine
preventing coking
is a more eco-friendly approach because
it allows the same engine to be used
over and over again
while not depositing toxic chemicals
into the atmosphere now we've never sent
humans to mars before
we've sent a ton of robotic missions
there but never actual humans
and now spacex is making it even easier
as recently as august 2020 spacex's
raptor engine passed a major milestone
in their engine development
process when their chamber pressure
reached 330 bar
without exploding this beats out the
previous record
held by the soviet union's rd 701 engine
and spacex's merlin engine to me this is
an absolutely incredible accomplishment
because it could be the foundation for
the interstellar travel that we've all
been waiting for
hey everyone i'm kenny harris a
satellite engineer and one of seeker's
new host
i've always been in love with space and
engineering so i'm extremely excited to
be able to share my interest with you
as a new member of the seeker family
thank you so much for watching this
video
and let me know what you think in the
comments below and if you want more
engineering news like this
go ahead and subscribe i'll see you next
time on seeker