I believe one would be hard pressed to prove it is. Nomenclature is what sways many to think such a term as,
astronaut, (a term coined in the 20's as relates to Sci-Fi) today marks no credibility for the subject of spiritual extra-terrestrial (not of earth) beings in ancient scripture.
What do we think Angels were?
Angelos "messenger, envoy, one that announces,".
Ezekiel and his wheel. The fire that guided Moses and the Hebrews through the desert.
Suffice to say, the human family leaves glyphs, earth shrines that aren't able to be discerned as a pattern or shape terrestrially but can be seen from above, like the Nazca plains. The Egyptian pyramids, like the great pyramid on the Giza plateau that is immense in its footprint and yet even in the deepest part of it there is no soot on the stones.
What does that mean? A question. How was that structure constructed when those deepest halls and chambers are pitch black for lack of natural light today, back when the pyramid was constructed? No soot!
In an age when electricity as we know it did not exist.
I'm familiar with Sitchin and his books though it has been years since I cracked one and read it over again.
In his career writing of these things he had a lot of critics. And yet, what were they except those who were arguing against what he and his knowledge of ancient Cueniform text, the first writing, extrapolated and brought forth for consideration?
He said repeatedly that he was not promoting his own agenda when he delivered these translations in his books. Rather, he was bringing to light what the ancients put on the record. And where there were breaks in those tablets, as scholars do with Bible fragments, he extrapolated what was there and what could be bridged as the message therein in absence of those writings. And yet, as he admitted, it did not mean that was the absolute conclusion to be reached. It was subject to change, because his was a matter of research in what was written by the ancient Sumerian (now Iraq region) culture.
A culture that recorded the Annunaki, ( "Those who from heaven to earth came". ) also related in the Bible as the Nephilim, and appearing in Genesis.
Were the Anunnaki the Nephilim in the Bible? - YouTube
I think if you are inspired to read his work you should do so and discern for yourself. And in matter of the charge that his work was "un-godly", consider that Zecharia Sitchin was a practicing Jew.
Do we think then he was an instrument of ha Satan? Or rather was he a seeker of God's wondrous and other mysteries?
You Tube -Sitchin
Then there's Hebrew scholar
Mauro Biglino.
And what he offers as relates to Anunnaki.
Keep in mind if you consider this, Genesis again.And the creation story that was predated by that what appears in the Sumerian text as the Enuma Elish.
We humans were created in the image and likeness of God. Remember also the plural texts such as that in Genesis 1:26. Let us make mankind in our image and likeness.
And the etymology of Elohim. The plural form of Eloh, God. Elohim being a singular or plural noun for God. (God's)
Follow where the spirit leads. Gnosis does not lead you to Hell. Ignorance does.