Hello, it's Scott Manley here. At SpaceX's facility in Boca Chica - people are working hard, very hard
I mean they've been working over the holidays weekends overnight on a giant stainless steel. Well starship, I mean
This is this is really kind of crazy normally looking at the quality of what they're building here out of you know sheet
Stainless steel with internal bracing I would not think this is a flight article. I would dismiss. I mean the people working on it are
Apparently there's a company on site that normally builds water towers which is why you know
One of the reasons why I thought it was a water tower, but you Elon Musk keeps telling us
No, this really is a starship
And of course I'm using finger quotes for starship because it's not going to the stars
but if you're one of those people that wants to complain about this
Please show with your also complaining of a Boeing Starliner and at Lockheed Starfighter
Otherwise, I'll presume you're biased against Elon Musk's specifically, but yeah
this thing I don't know it it's being pitched as a starship hopper and
well what we see now is that it's in three sections and they do come down and they should in theory bolt together. We can
see tabs, and we can see bolts. The top two sections are much more polished stainless steel and they look just to be empty
Whereas the bottom section with the legs appears to have had a lot of stuff being put into it
it has vent holes it now has rocket nozzles and that
Those are worth talking about on their own. It also has landing legs, which they've actually
Covered up with a sheet steel. I believe to make them look like fins, but the engine nozzles
That's really interesting. Now, we can't tell whether these are real Raptor engines
But there's one curious feature
That's got everyone talking and that is the shape of the engine Bell, has this weird kink in it, now
That's not something that's been seen on any rocket that's been flown before but it is a legitimate
Technology. So if these are just placeholder engines, why would you build this complex engine shape?
Maybe they are actual engines.
So the the kink in the nozzle is a design. It's called an altitude compensating nozzle,
if you watch my video on rocket nozzles, you'll know that to get maximum efficiency from a rocket
You want the nozzle to expand slowly enough so that when the exhaust leaves it matches the exterior pressure
that way it doesn't expand out and waste energy
So this means that vacuum nozzles nozzles designed for deep space tend to be much wider
If you look at the Falcon 9 the first stage engines, there's nine on the first stage, but on the second stage
There's a single Merlin engine with an engine bell that covers almost the entire width of the rocket
Now the problem is if you have an engine bell that big then if you use it at atmospheric
you know sea level as the engine exhaust comes out
It kind of it has to detach from the interior of the nozzle because the atmospheric pressure is pushing inwards
so it creeps up the side and
Causes the rocket exhaust to detach at some point and it's not going to be symmetric. It's an unstable situation
So it creates these big banging forces in either direction
So you have to have two different engine sizes. The Space Shuttle has a weird
lip on it to compensate for this but
This to state this is what we think of as a two-stage nozzle
It's got one section
Which is quite narrow and then it has a big lip on the inside where the flow separates out and produces a clean exhaust
then at lower pressures higher altitudes
it's imagined that the flow still has enough power or has enough pressure over there ambient to slip over this Ridge and then
Use the full engine nozzle
so in theory this engine
Works well at low altitudes and then once it reaches a certain altitude
the flow starts to use the full nozzle and it gets higher specific impulse.
Now, obviously at low altitude you're paying a bit of a weight penalty for this, uh,
heavier nozzle and at high altitudes you've got this ridge, which is kinda ruining your perfect flow out the outside
But it seems to be a nice compromise solution
If you are say building a spaceship which needs to be able to land on earth and also
Operate in the upper atmosphere and we know that the Raptors on the upper stage of the starship are supposed to do that
So, you know, this has been tested I've seen some papers on I was very helpfully linked those and read them. It does show
Yeah, you get as you go through this transition
there's a
It's kind of not entirely smooth to so you could start up which is kind of rough
And then as you'd fly through this you get these site loads which bang the thing around a bit and then you get smooth flight
after that
And then if as you're coming down the reverse happens this may not matter on
the starship because the starship of course is gonna light its engines in the upper atmosphere and then or relight
When it's coming down presumably by the point the atmospheric pressure has become high enough. There's only using the interior nozzle
But I imagine you could also adjust your throttle to cleanly push through this as these transitions as quickly as possible
So ask the question as to whether this thing is gonna fly. I mean like as I said Elon telling us it's gonna fly and
It doesn't look flight worthy. But you know, they're building it in a tent which I'm gonna say is hardly a
Point against it because Elon Musk has built lots of things in tents, which became real objects
The SpaceX back in November did apply for an FCC license to operate a radio equipment RF equipment at altitude.
They talked about the tests in that know the exact and the actual application is secret
but the FCC had to share some details of it and they talked about test flights that go between
up to 500 meters and then later up to 5,000 meters that's 15,000 feet and
durations of up to 5 minutes, so
Yeah, looking at this and knowing what we know about the Raptor, knowing what we know about the density of methane and liquid oxygen
Well that bottom stage should have enough
Tank volume to actually contain enough fuel for five minutes of flight with an object this size. So
That is reasonable on the other hand
We haven't seen any of these
Carbon-fiber tanks getting shipped and we build the carbon-fiber
Tanks right now in Los Angeles and it's a 9 meter tank so that you'd have to ship this via barge
I don't know where they would have brought this in. So there's not one of their fancy new carbon-fiber tanks in there
Maybe they're gonna just, you know, weld some bulkheads in. Hey, you know, they got water tank company on there
I I just don't know there's so many questions going on about this and
Obviously looking forward to seeing what happens here
and the I mean the other question is
Why are they working so hard that it really doesn't make so too much sense to me
But there's a couple of reasons first of all
They're launching the DM one mission
That is the test of the crew program the Dragon 2 capsule that is supposed to launch in January
It was originally scheduled for about the 17th. I think I forget but at this point
it's been definitely delayed because there's a lot of stuff that they cannot do without official sign-off from government and
Government is of course shut down. They have been putting on the launch pad and putting it vertical
So those photos that came out yesterday?
It's yesterday off the Dragon 2 capsule with its the trunk section is now half coated in solar cells
Which is kind of cool unlike other spacecraft. It's not going to fold out a solar panel and flight
It's just got the solar cells stuck to the outside. So that's been tested that's getting to top. I don't know
when you know how much NASA is gonna be able to support them on this and when they're gonna be able to fly this but
At the same point at the same time. It does seem reasonable. They might get it out before the end of January
So maybe they want to have this shiny stainless steel starship on show at least before the end of the month
the other possibility is that
They haven't got investors from the government. You know, they were passed over for various government grant options recently. So
Maybe they're doing this to try and pitch it to investors. Also, perhaps their one public investor Yusaku Maizawa
Perhaps he has some you know
Contingencies some milestones that have to be hit in that make his funding contingent on those
So perhaps they're pushing this together as quickly as possible to get something flying
as it stands, you know, I don't know why you would make it from stainless steel because if your plan is
You know stainless steel for re-entry testing
Then this isn't gonna be flying fast enough for that this I'm not even sure it's just gonna be flying like the grasshopper
did it's just gonna be a whole lot bigger and
Looking like a giant Christmas tree ornament to be honest. I
Don't know why you would need three
Raptor engines so
Because I think somebody that the math has said actually the Raptor spec should be good for one, but you know
I guess having three allows them to test more, you know different reentry or landing options
yeah, there's just so many questions about this thing and so many cryptic comments from Elon and
leaks from SpaceX
Yeah, I would love to know what you guys think. I'm Scott Manley fly safe
