Finjan made the outlandlish claim during a press conference in the southern Iraqi province of Dhi Qar.
In a speech, he said that the ancient civilisation had built the world's first airport in the area around 5,000 BC.
Finjan went on to claim that the airport had served as a hub for space exploration, and that the Sumerians discovered Pluto falsely claiming it to be the solar system's "twelfth planet" and discovered by NASA.
In front of a beleaguered audience Finjan sought to back up his claims asking sceptics to study the works of Sumerian experts such as Russian professor Samuel Kramer.
The academic wrote about the Sumerian awareness of the solar system evident in the ancient society's creation myths.
The Sumerians represent the oldest known civilization in Iraq and according to historians reached their peak in 2,700-2,400 BC when Iraq - or ancient Mesopotamia - was regarded as the "cradle of civilisation".
However, most hold that the first manned space journey took place under the Soviet space programme in 1957.
Cosmonaut Yuri Gagarin boarded Vostok 1 and embarked on a single orbit of the Earth lasting 108 minutes before Gagarin ejected at 23,000 ft and parachuted back to earth.
It's still not clear if he spotted any ancient Sumerians on his intergalactic travels.
|— Hayder al-Khoei (@Hayder_alKhoei) September 29, 2016
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