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There are a number of videos of the Starship "serial number 6" or SN6 test hop but this is the official SpaceX one. As such it is shot by a drone and has some shots of the Raptor engine during the flight.

I have always been a rocket/space enthusiast (was planning to be an Astronaut until my vision stopped being 20/20) and one of my favorite books on the subject is Sutton's "Rocket Propulsion Elements." One of the things that was clear from this text was just how difficult it is to manage the thrust of a rocket engine. Many engines had 2 or maybe 3 "settings" but the continuously variable thrust of the Raptor was pretty much considered "impossible" for a long time.

The issue is no one goes back to the primary sources enough? Because life is short and death is forever, we don't have the time to master all the primary sources on all possible topics. So we have to rely on secondary sources for most of our knowledge. That isn't unique to history, that's true of every damn subject.

I actually worked my way through most of Rocket Propulsion Elements by Sutton a few years ago, actually doing the math on how rocket engine design works (I was thinking about building my own as a hobby- had a kid instead and all that free time vaporized). It took me ~9 months of working in my spare time from my day job that had nothing to do with rockets. I don't think it's reasonable to expect people to only have an opinion/understanding if they've done all the work themselves. So we have to rely on secondary works, done by people who have an understanding of the primary sources/equations/whatever. That's not "the reality of the state of the study of History" that's the nature of humanity.

The standard text on the matter is "Rocket Propulsion Elements", by George Sutton. Another recommended reference is "Design of Liquid Propellant Rocket Engines" by Dieter K.Huzel and David H.Huang.

He's talked rocket design specifics on many occasions and "built his own rocket" according to Vector Launch CEO Jim Cantrell [1]:

>He borrowed all of my college texts on rocket propulsion when we first started working together in 2001. We also hired as many of my colleagues in the rocket and spacecraft business that were willing to consult with him. ... I found out later that he was talking to a bunch of other people about rocket designs and collaborating on some spreadsheet level systems designs for launchers. Once our dealings with the Russians fell apart, he decided to build his own rocket and this was the genesis of SpaceX.

Additional info from Jim from a follow-up interview[2]:

>Cantrell ... loaned him some textbooks to study. The books were "Rocket Propulsion Elements," "Aerothermodynamics of Gas Turbine and Rocket Propulsion," "Fundamentals of Astrodynamics," and the "International Reference Guide to Space Launch Systems." He would quote passages verbatim from these books. He became very conversant in the material. ... Musk would absorb this information and then hold his own in conversations — and he didn't hold back.

Additionally, Ashlee Vance's biography [3] describes his day-to-day as "quite involved with rocket design" at SpaceX and goes into a lot of detail about spending time on the floor assisting SpaceX scientists with their designs.

Obviously any single person at a company the size of SpaceX doesn't individually design and build a rocket by themselves, but it's generally agreed upon that Elon is knowledgeable in rocket science and contributes many ideas to the designs.

[1] https://www.quora.com/How-did-Elon-Musk-learn-enough-about-r...

[2] https://www.businessinsider.com/how-elon-musk-learned-rocket...

[3] https://www.amazon.com/Elon-Musk-SpaceX-Fantastic-Future/dp/...

See also: "Rocket Propulsion Elements", by George Sutton. Now in its 9th edition.

"Confused" is probably not the correct word here, if this journalist is similar to western journalists then I would expect them not to have any idea how rockets work or even a passing knowledge of physics. Combine that with a language translation stage and well, accuracy is probably not high.

The book "Rocket Propulsion Elements" [1] which is pretty much everything known about rockets that isn't classified, is pretty dense for a reason. I certainly don't hold it against the journalists who are trying to do their job as best they can.

That said, because launching heavy things into space can also be used to launch heavy things around the globe and into other peoples territory, there are aspects of the technology that are closely watched. One of them is cryogenic turbo pumps. These are pumps which can pump a cryogenic fluid at high pressure and flow rates. Those are an essential part of the space puzzle because once you get a functional cryogenic rocket engine you can add additional engines and fuel at a relatively constant mass/payload ratio. And then that means if you have a payload of mass X, and an orbit of O (or sub-orbit if you're talking ICBM) you can build a delivery system to make that work. Of course other controlled technologies are guidance systems and launch 'racks'.

If Iran was looking for something more than a PR ploy I think they should host a middle east space conference with peer reviewed papers. To get to where SpaceX is, and where Iran wants to be, is rocket science but it is also achievable rocket development. Open discussion would lend an air of legitimacy to the research (today most westerners assume its simply a quest for missile technology) and probably advance their programs more effectively.

[1] http://www.amazon.com/Rocket-Propulsion-Elements-George-Sutt...

In his interviews with Tim Urban from Wait But Why, there's a bit of detail about what he read leading up to his founding of SpaceX. They're all hard science texts – Rocket Propulsion Elements (Sutton), Aerothermodynamics of Gas Turbine and Rocket Propulsion (Oates), Fundamentals of Astrodynamics (Bate). From everything I've heard, he's well-versed in the material in a way that not many CEOs are.