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if you've been following starship from
the very beginning you will know that it
didn't always look this good
the first starship prototypes looked
incredibly rough not like something that
could ever survive a journey into space
the starships that spacex produce now
look much more sophisticated with
smoother metal work and welds that are
much less noticeable
so how did starship go from looking like
this to this in just a few years
and will it ever look completely smooth
and shiny like it does in the renders to
answer this question we need to look at
why starship looks like this in the
first place more specifically why it's
big and shiny instead of white and thin
like most rockets
starship wasn't always destined to look
like a 1940s sci-fi rocket in fact it
was originally meant to be made from
carbon fiber and production had already
begun in california this seemed like the
most logical plan since carbon fiber is
extremely strong and spacex already had
most of their workforce based in
california
so it shocked everyone when a stainless
steel starship popped up in a small
village in texas
but over time people started to realize
what a great decision this was
although carbon fiber is very strong it
breaks down at around 200 degrees
therefore it would require a very thick
heat shield in order to survive the 1600
degree temperatures during multiple
re-entries
although stainless steel is heavier it
can deal with much higher temperatures
and so only a very thin heat shield
would be required stainless steel is
also much cheaper than carbon costing
just three dollars per kilogram compared
to an incredible 150
but this wasn't the first stainless
steel rocket to be made
back in the 60s nasa made an atlas
rocket out of an incredibly thin
stainless steel this was so thin that
unless the rocket was constantly
pressurized gravity alone would
completely crush it and it did
but even if spacex had gone with carbon
fiber it's hard to see how starship
would have actually been made
in order to manufacture carbon
composites the fibers have to be layered
in a very specific way in order for the
material to be strong in every direction
then the composites need to be cured in
an enormous pressure oven for starships
nine meter wide sections spacex would
need an oven larger than anything that
exists at the moment
this is where stainless steel excelled
it could be put together quickly using
the most basic and affordable methods
and so spacex began working on the
world's shiniest rocket but for some
reason it wasn't so shiny
one of the biggest challenges with the
initial starship prototypes was the
welding
initially each ring had to be made out
of several sheets of 301 stainless steel
which were 4.5 millimeters thick don't
forget that the original starship crew
was contracted from a water tower
company and didn't have any experience
with building rockets
so the welding standards were well not
great
but what exactly is welding and why is
it so difficult to get right
webster's dictionary defines wetting
as
the fusing of two metals with a hot
torch
the early starship prototypes used a
welding method called flux core with
this method a voltage is passed through
a metallic wire which forms an arc
between it and the metal causing it to
melt the tip of the metallic wire also
melts and falls into the now molten
stainless steel filling up any cracks or
air bubbles with flux core the metal
wire is surrounded by a solid material
that burns and releases a protective gas
around the weld
this protects the weld and stops it from
reacting with the oxygen in our
atmosphere which would cause corrosion
this works well when you're inside a
controlled environment but spacex's main
problem at the time was they didn't have
a proper factory just a fairly large
tent and so with most of the welding
being done outside by welders that had
no rocket experience it's no surprise
starship looked so bad
the welds on the first prototype were
heavily corroded with cracks and rough
edges on the surface
in order to improve these welds spacex
started grinding them down until they
were flush with the surface
although this seemed like a poor attempt
to restore some shininess this process
was actually done to strengthen the
welds
these sharp edges and tiny cracks act as
pressure points which could lead to much
bigger cracks once starship is
pressurized and so grinding the surface
removed these defects and reduced the
chance of a weld failing
in theory each weld would be as strong
as the surrounding metal but the initial
starship test proved that it wasn't
mark 1 exploded when one of the welds
failed and sent the bulkhead flying and
so spacex brought in some major
improvements to the next starship
prototype
each ring was now made from thinner
single sheets of stainless steel which
required much less welding they also
moved from 301 to 304l stainless steel
which was more resistant to corrosion
when welding
at this point they also upgraded to tip
tig welding which gave them much more
control over the welding arc allowing
the welder to tighten it up and weld
much deeper into the metal
this produced thinner welds and didn't
warp the surrounding metal nearly as
much
spacex also started to buy robotic
welding machines similar to the ones
seen in tesla factories
with these upgrades spacex automated a
large chunk of the process and started
to produce cleaner and more precise
welds they also began installing more
stringers on the inside of starship's
hull to stop the metal from buckling
under its own weight
but spacex didn't stop there by now
spacex has likely moved on to laser
welding for many of starship's sections
with laser welding the heat is much more
concentrated and goes deeper into the
metal allowing the ring segments to be
welded in a single pass
but in order to really improve the
strength of each weld another process
has to be done
you see when starship stainless steel is
produced in its factory it goes through
a process called cold rolling this
involves passing the metal through a
series of rollers which can press it
down and stretch out the grains in the
metal this makes the material stronger
and harder
however when starship is welded the heat
causes the metal in that area to soften
up again
this is where spacex's giant planishing
machine comes in planishing involves
hammering the welds down and compressing
them until they match the hardness of
the surrounding metal this has the added
benefit of smoothing the finish of the
welds and improving their look
but will starship ever have a completely
smooth finish like a mirror
to answer this we need to go to chicago
to look at the famous bean sculpture
made from several stainless steel sheets
the structure went through an
eight-month polishing process involving
a crew of 24 people using many different
grades of sanding grit in order to do
this on starship the entire body would
need to go through this process to avoid
having any visible lines around the
welds so it's unlikely that spacex will
ever do this
either way spacex is throwing everything
into starship and it's amazing to see
this project come together so quickly
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