On April 20, 2023, SpaceX conducted its first
integrated flight test of the Starship and Super Heavy booster. This was a monumental achievement for the
Starship program, even though they failed to reach orbit on their first attempt. For the most part, I think we can all agree
that during this test, Starship performed much better than expected. But one could argue that there were also few
opportunities for improvement. As you all know, it took nearly 15 seconds
for Starship to clear the pad, and by the time it did, Booster 7 managed to completely
annihilate the blast surface under the orbital launch mount. This outcome made it painfully clear that
a flat concrete pad located 16 meters below the vehicle would not be enough to support
33 Raptor engines operating at full thrust. While they didn't expect the results to be
as severe as they were, SpaceX was well aware of this fact beforehand. We know this because at the time, they were
already more than six months into developing a new system that could fight back against
the world's largest blowtorch. Fast-forwarding to the present day, it's been
just over two months since the Starship integrated flight test, and crews have been working 24-7
to install a massive, water-cooled steel blast surface ahead of the next launch attempt. As of now, SpaceX is finally nearing the first
major milestone in this process, which is to repair the foundation of the orbital launch
mount. In today's episode, we're going to take an
in-depth look into how SpaceX is accomplishing this retrofit while building around the existing
systems. If you're looking for the How It's Made episode
of Stage 0 2.0, then you've come to the right place. My name is Zack Golden, and welcome to another
CSI Starbase deep dive investigation. Hey everyone, thanks for joining us. On the 19th of May, SpaceX shared this footage
demonstrating a proof of concept of their new protection system for the orbital launch
mount. The goal of this transpirationally-cooled
steel sandwich is to maintain a layer of water between the exhaust plume and the steel plates,
in order to prevent them from melting or disintegrating. This seems to work very well during the single-engine
test. But with all 33 engines firing, there will
still be a tremendous amount of force transferred into the ground through the steel plates. For this system to be successful, the foundation
used to support it will need to be significantly stronger than the original design in order
to prevent the same thing from occurring again. As always, before we get started, I want to
quickly define a few terms that are going to be repeated frequently throughout this
episode. Since we are going to be discussing foundation
repair work, we need to understand the main components that make up the foundation of
this structure. These components include concrete pilings,
a blinding layer, and finally the pile cap. Let's start with the concrete piles. In civil engineering and construction, piles
are long cylindrical structural elements which can be made of steel, timber, or in this case
concrete. They are used to transfer loads from the above-ground
structure into the deeper layers of soil or rock. These are especially useful in situations
where the existing subsoil layer near the surface does not possess sufficient bearing
capacity to support the structure. Next there is the blinding layer, which refers
to a thin layer of concrete or mortar that is placed over the prepared ground before
constructing the foundation. The purpose of this blinding layer is to provide
a clean and level surface for subsequent construction work. The blinding layer also has a secondary purpose
of distributing the loads from the structure to the underlying soil and preventing the
upward movement of groundwater. Finally there is the pile cap, which is a
reinforced concrete slab or structural element that connects and supports a group of piles. It's constructed on top of the blinding layer
and is used to evenly distribute the loads from the superstructure onto the individual
piles. Now that we have a common understanding of
these terms, let's take a look at the process for constructing this new, massively upgraded
foundation. The first step of this process was to excavate
all of the old material from under the orbital launch mount. This includes getting all of the damaged pilings
out of the way and removing any debris that was left over from the failed blast surface. During this time, water was constantly being
removed from under the OLM using several pumps. After the excavation process was complete,
they backfilled the area with sand and gravel in order to prepare for the new auger pilings. There were two separate types and sizes of
pilings used under and around the orbital launch mount. These were installed in three separate zones
and each of these zones serves a different purpose. First we have what are known as rotary board
pilings, or RBP for short. These piles are started off by drilling a
shallow hole into the ground and then lowering a steel casing into the hole. These casings varied in length, but they were
all about 4 feet or 1.2 meters in diameter. After this, the casings are driven into the
ground using a vibro hammer. The primary purpose of this casing is to prevent
the shallow layers of subsoil from collapsing into the hole. As a secondary function, it is also used as
a guide for the auger as it bores the remaining hole roughly 35 meters down to its final depth. Once this is complete, huge rebar cages are
carefully lowered into the hole and then it is filled with concrete. After the concrete has cured to an acceptable
level, the above ground section of the casing is cut away from the concrete piling. There were 8 of these RBP pilings arranged
in a circular pattern with one more in the center for a total of 9. These are also used to provide support for
the direct blast surface. The original design featured 24 auger pilings
instead of 9. However, these are a larger diameter and likely
much deeper as well. There are 15 more of these RBP pilings installed
outside of the original tension band of the foundation. The placement of these piles creates a bit
of an odd pattern. In general, we would expect it to be somewhat
symmetrical considering there is an equal amount of high pressure exhaust gases escaping
in all 6 directions coming from under the orbital launch mount. Unfortunately there are a few obstacles in
the way of designing a symmetrical base. I'm referring to the concrete trenches that
straddle the launch mount on the eastern and western sides. Originally, I expected that when this job
was performed, SpaceX would end up temporarily cutting into and removing sections of these
ground support equipment trenches. This actually was done on the eastern side
of the launch mount, but likely because these pipes were damaged during the launch event,
so they needed to be replaced either way. Had they done this on the opposite side, we
would have probably ended up seeing 2 RBP piles placed symmetrically between each of
the legs for a total of 12 piles. The problem with cutting into the culvert
on this side is that there are 3 times as many cryogenic and high pressure gas pipes
in here that feed not only the launch mount, but the integration tower as well. It appears that SpaceX was unwilling to break
into this culvert, which is understandable, because it would have probably added a lot
of difficulty to the project and increased the amount of time it takes to get this orbital
pad operational again. As a result, they were unable to place large
RBP piles between these two legs. To compensate for this, they placed 2 additional
piles in this direction and 3 on this side. Some of you are probably wondering how additional
supports on these sides makes up for having zero support in this area, and that's a very
good question, but we will return to that here in a bit. While we are on the topic of strong foundations,
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below. Alright, returning to the orbital launch mount. Let's quickly discuss the second type of piling
used here, which is known as a continuous flight auger piling, or CFA pile for short. CFA piles use an auger similar to what is
used in the RBP pilings, except there is a hollow tube in the center of the drill bit. This allows concrete or grout to be pumped
through the center. In this method, the hole is drilled all the
way to the desired depth, and then the concrete is pumped into the hole as the auger is withdrawn. From here, the reinforcement cage is quickly
lowered into the pile while the concrete remains fluid. From what we have been able to locate so far,
there are 11 of these CFA piles scattered around the launch pad area. These are much smaller than the 24 RBP piles
and are around 18 inches, or half a meter in diameter. All 11 CFA piles are located outside of what
we will consider to be the foundation of this structure. This means that they are probably being used
as anchors for the concrete outside of the base structure, and should prevent large slabs
of concrete from being ripped free, similar to what we observed in the aftermath of the
integrated flight test. We believe there is a chance that there are
additional CFA piles in some of these open areas that haven't been uncovered yet. But as it currently stands, it seems that
the locations were chosen almost at random due to the fact that there are still large
areas of unsupported concrete. In my opinion, there is a chance that these
may not even be necessary at all if the water-cooled steel plates under the launch mount perform
as well as anticipated. Anyways, the next step in this process was
to excavate all of the backfill material that was brought in prior to the installation of
the auger piles. For this, SpaceX needed to dig down nearly
15 feet, or 4 meters, from the height of the original blast surface. Digging this deep into the ground puts the
bottom of the excavated area roughly 2 meters below the local water table, which creates
a bit of a challenge for the construction process. The biggest issue is dealing with the water
that will seep in from below the surface. But there is also possibility of water entering
through the sides, which could cause instability in the subsoil surrounding the excavated area. Preventing this from occurring required a
two-step solution. The first was to create a water-tight perimeter
around the entire foundation of the launch mount. This was accomplished by installing walls
of sheet pilings into the ground to enclose most of the area. Sheet pilings are long, corrugated steel panels
which are designed to interlock with each other. This helps to keep the water-saturated perimeter
walls from collapsing into the excavated area, but it's not enough to prevent groundwater
from rising to the surface. For this, a dewatering system was installed
along the perimeter of the barrier wall several weeks before the excavation work would take
place. This type of dewatering system is known as
a well-point system. There are several ways of installing a system
like this, but in this case, a hollow pipe is drilled about 6 meters into the ground
using a small drilling rig. This is similar to what you would use if you
were attempting to take a core sample, except there is a water jet in the center of the
pipe that displaces all of the sand and soil as it's being cut away. This creates a water-filled hole in the ground. After this, a riser or well-point, which is
essentially a PVC pipe with a small opening on one end, is lowered into the hole. Then a filler material is added between the
pipe and the well bore. This holds the pipe in place and also acts
as a filter. Shout out to Starship Gazer for capturing
this footage to help us explain this process. Once the network of well points are installed,
they are connected to a larger pipe manifold using collection hoses. This manifold is connected to an external
pump, which is used to pull a partial vacuum on the tubes. The suction force will extract the water from
out of the ground while leaving the sand in place. This dewatering system is an effective method
of temporarily lowering the water table several meters below its natural depth. This ensures that the excavated area doesn't
turn into a giant swimming pool. Anyways, with the dewatering system doing
its job, SpaceX was able to proceed with the excavation work. As they were removing all of the material,
they also demolished the original hexagonal tension band between five of the legs. As you all know, good old Booster 7 handled
the first one. The concrete was completely removed, but several
meters of rebar were left intact on either side, which would later allow them to be tied
in with the reinforcement cages for the new foundation. As I mentioned earlier, all of the casings
for the RBP pilings had been cut away, leaving the tops of the columns exposed. Each of these will have to be cropped down
to the height of the eventual blinding layer. I've explained this before in a previous episode,
but using a cropping machine like the one shown in this example, the concrete can be
pulled free while leaving the rebar intact. After this, the rebar is cut down below the
height of the future pile cap. Just like the demolished tension bands, this
will be used to tie into the massive pile cap. With the concrete piles cropped down to the
proper level, the first half of the blinding layer was set. This concrete base covers the north side of
the base structure and also the entire surface under the launch mount. We aren't sure whether or not they ever completed
the remainder of this blinding layer or if they went straight into laying down rebar
on the south side of the structure. The density of these layers of rebar makes
it nearly impossible to tell whether or not there is concrete underneath it. Moving ahead to the present week, we can finally
see the full shape of the pile cap. On the south side of the pile cap, you can
see that there is actually two separate tiers for the rebar formwork. Looking at the lower level, which is where
all of the pipe manifolds will rest, you can see a gap in the formwork which will create
a ditch for a large water pipe to run underneath another part of the manifold. Thanks to Ryan Hansen's base, we can see what
this will look like. There are two separate pipes that will feed
the water-cooled plates under the launch mount. When we move around to the north side of the
OLM, we can see that there is only a single tier of rebar cages. Without a step down in the concrete, it seems
unlikely that there will be any water supply manifolds on this side of the launch mount. Those of you who are returning viewers to
the channel will remember that we initially expected the water supply to encircle the
launch mount, passing under the GSE pipework that runs up the leg on the west side of the
structure. This would have supplied water from all six
sides, which is how the equivalent system at pad 39A was designed. But that is clearly not the case considering
SpaceX has already begun reinstalling the cryotubes and they appear to be forming the
foundation around the pipes instead of replacing the preformed U-shaped concrete culverts. This means that we should not expect to see
any supply manifolds feeding the water-cooled steel plates on this side of the launch mount. With the way this system has been designed,
or possibly redesigned, the three manifolds on the south side of the table will send water
across the blast surface to supply the sides that don't have manifolds. In order to mount these massive steel plates,
there needs to be a way of anchoring them to the foundation. So while these rebar cages are being laid,
several cranes have been busy placing steel embeds on top of the rebar cages. An embed is a steel plate that typically has
studs welded to one side. This is the side that is embedded into the
rebar cage and will later become part of the concrete structure. They are used as an interface between the
concrete and structural steel members. On the top side of these plates can either
be a flat surface for welding or threaded studs to allow structural members to bolt
down onto the surface. There are square embed plates placed in various
locations in the lower tier which are likely for attaching brackets that will be used to
support the pipe manifolds. There are also significantly larger U-shaped
embed sections which is where the water-cooled steel plates will actually rest on. These are placed between each of the six legs
to form a pattern like this. The edges of the steel sandwich will rest
on top of these embeds which will give them a surface to weld them in place. You can see that there is a different design
for the positions where the water manifolds will be located. So with the remaining formwork installed around
the perimeter of the lower level, they were able to begin the first half of this massive
concrete job. The bottom layer of this foundation is about
1.8 meters thick and the top layer is 2.2 meters, so this job had to be divided into
two sections. Starting at 10pm on June 25th and continuing
over a period of 10 hours and 47 minutes, 132 mixer trucks were used to deliver just
over 1000 cubic meters of high strength concrete. This number is assuming that each mixer truck
has a capacity of 7.6 cubic meters. We expect the second layer will require about
858 cubic meters, so that will be an additional 113 loads. For those of you who are wondering, this is
roughly 4600 tons of concrete and enough to fill 3 quarters of an Olympic sized swimming
pool. Overall, this is a drastic upgrade from the
original foundation. Looking back at it one more time, in the original
design, the actual foundation was the six piles that tie into each of the legs and the
tension band that joins them together. In the center of the pad was the blast surface,
which in my opinion was a completely separate structure because it didn't actually tie into
the tension band or the six columns. As we mentioned, the blast surface was formed
using 24 CFA pilings and there was a concrete pile cap that was about 18 to 36 inches thick
and on top of that was 8 to 12 inches of Fondag RS. I'm not certain of these numbers, but this
is what I was able to determine by examining the debris that was left over after the launch. As we covered in our deep dive investigation
into the aftermath of this flight test, SpaceX was essentially relying on this layer of Fondag
to protect the concrete pile cap underneath. The expected mode of failure here would have
been for the booster to burn through the layer of Fondag and then destroy the pile cap, but
that is not when it ended up occurring. Instead, the pile cap failed first as it bent
under the force of the stagnation pressure from the Raptor engines. Had the blast surface been structurally tied
into the foundation, there was a good chance that the outcome would have been much different. This time around, the 9 pilings under the
blast surface, 6 original pilings for the leg columns, and 15 perimeter piles are all
tied together to form a massive foundation capable of redistributing the expected load
across a much greater surface area than before. The next step after this will be to install
the upside down shower head. At this point, we have only seen about half
of the water cooled plates that will be involved in this system. In the weekly flowers from RGV Aerial Photos,
we have seen the rectangular plates for the three sides of the blast surface that will
have water manifolds attached to them. We have also found three of the six trapezoids
that will make up the ring around the central hexagon. But, we still have not seen the plates for
the three remaining sides, which will not have a direct water supply, nor have we found
the triangular sections that will be located in the center of the pad. We believe all of these missing sections are
currently hidden inside of this inventory tent at the Sanchez site. Looking through the open doorway, we have
been able to see at least one or two of these plates being worked on inside of here, but
that is only a fraction of what is missing and we can't even say for certain which pieces
we are viewing, although they do appear to be the rectangular sections we are looking
for. The only problem is that this piece has large
holes on the end of it, which are threaded as if pipes will later be fit into those positions. But from our current understanding… Woah. What the f**k. Okay, so, time out. As I'm recording this episode, it appears
that SpaceX has just removed the sidewall of this inventory tent and we are finally
able to see what is on the inside. Shout out to Starship Gazer for capturing
this footage, because this fills in a lot of blanks for us. As you can tell, it appears that the centerpiece
for this system has been welded together as one massive section. This was quite unexpected, but it should drastically
reduce the amount of time it takes to install this system once it is ready. Give me a few minutes, I'm going to see if
Ryan can put something together for us. Alright, thanks to some quick work from Ryan
Hanson Space, we can see what this massive section looks like when viewed from above. By the looks of it, there are still at least
three missing sections that will end up resting on top of these embed plates. It will be interesting to see how SpaceX is
able to maneuver something this large under the launch deck. There is zero chance of this being lowered
in through the top of the launch mount, even with the clamps retracted. Because of this, it will actually have to
be transported in vertically between two of the legs, using this custom transport stand. From there, it can carefully be lifted into
position from above. This is an extremely tight fit, so it will
take some finessing to get it into position. Because this was a rather last minute development,
we will cover it more in depth in part two of this deep dive investigation. While we wait for the next steps to be completed,
let's check in with the other component of this system which SpaceX has been making a
lot of progress on. As a lot of you are aware by now, the high
pressure water system is located on the opposite side of the integration tower from the orbital
launch mount. Four water supply tanks were installed shortly
before the integrated flight test. These were delivered to Starbase in February
of this year along with several large sections of pipe and these two manifold pieces right
here. We initially believed that these were intended
to control the flow of water to the deluge system. These have since disappeared and have likely
been scrapped so it's possible that they were never part of the design. However, it wouldn't really make sense to
transport them all the way from Florida to Texas just to end up scrapping them, so we
do believe that there was some sort of change in plans. In place of where we expected these manifolds
to be located, they installed two even larger water tanks next to the original set of four. There is space for a third tank and the pedestal
is already on site, so we believe an additional one will be transported across the country
in the coming weeks. These tanks were originally used as vertical
storage tanks in their past life, so there is a bit of modification work that will need
to be performed. In particular, they will be installing large
flanges onto the bottom of the tanks, similar to what exists on the first group. These flanges will connect to a 4 foot diameter
manifold that runs along the larger 5 foot diameter pipe for the four smaller tanks. So as you can tell, there are two separate
water supplies feeding the water-cooled plates, which gives this the appearance of a two-stage
water system, although we are unsure if that's actually the case. One interesting thing to note is that the
larger storage tanks have a smaller discharge manifold than the first group of tanks. For this reason, it seems like the smaller
water tanks are meant to be emptied in a rather quick burst, lasting just a few seconds, while
the larger tanks could be a secondary water supply for longer duration tests. As of now, SpaceX has begun to assemble the
high-pressure gas discharge manifold, which would be used to split the gas supply between
the two groups of water tanks. As you can see with the first group of tanks,
the gas is injected through a port in the top, which forces the water out at the bottom. The flow of gas into the water tanks, and
likely the pressure as well, are regulated by the number of valves open on this manifold. After the water leaves the tanks, it turns
upwards into what is known as a weir pipe. At the apex of this weir, there is a small
pipe that branches off from the top, which is likely an anti-siphoning vent. This system is still incomplete at this point,
so we will hold off on explaining how all of this works for now. There are a large number of high-pressure
gas tanks sitting off to the side, which are yet to be installed, as well as several other
components which I believe are still missing from this area. With that being said, we will pick up where
we left off in part 2 of this deep dive investigation. If you enjoyed this episode, then do us a
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and check out some of our recent investigations that you may have missed. This is our 20th episode, and we're hoping
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of these episodes and can also gain access to the CSI Starbase Discord server. I want to say a huge thank you to all of our
current members, because without you, we seriously wouldn't be able to do this. Before we go, I also want to thank all of
the photographers and 3D artists whose content was used in today's investigation. You can find the links to all of their various
platforms in the description. Last but not least, thank you to Squarespace
for sponsoring today's episode. I hope to see you all on part two of this
deep dive investigation. For now, this is Stage Zero Zack signing off.
