Asimov's role model in this regard was Willy Ley.
(Heinz Haber, Wernher von Braun and Willy Ley)
Willy Ley was born in Germany on December 2, 1906. He grew up in Berlin, and studied astronomy, physics, zoology, and paleontology at the University of Berlin.
After reading Hermann Oberth's book Die Rakete zu den Planetenräumen (By Rocket into Interplanetary Space). He himself published Die Fahrt in den Weltraum (Travel in Outer Space) in 1926, and became one of the first members of Germany's amateur rocket group, the Verein für Raumschiffahrt (VfR - "Spaceflight Society") in 1927. He contributed many articles to its journal, Die Rakete (The Rocket).
In 1935, Ley left Nazi Germany. He first went to Great Britain, but finally settled in the United States. In 1936, he supervised operations of two rocket planes carrying mail at Greenwood Lake, NY.
An avid reader of science fiction, he began publishing scientific articles in American science fiction magazines, beginning with "The Dawn of the Conquest of Space" in the March 1937 issue of Astounding Stories. Ley had a regular science column called "For Your Information" in Galaxy Magazine from its premiere in October, 1950 until his death.
The young Isaac Asimov, therefore, read Ley's articles. His own stories written during the late 1930s were science fiction, but after the war, and after he'd earned his degree, he began trying his hand at non-fiction essays. He wanted to have a regular column, like Ley.
He got his chance in 1957.
A little before September, 1957, Bob Mills, editor of the science fiction magazine Venture (a sistermagazine of Fantasy & Science Fiction) decided he wanted to do a science column, and asked Asimov to write it.
I agrred enthusiastically, for this was just the sort of thing I wanted. I was to make each column 1200 words long and I was to be paid $50 for each column. What's more, I was to have an absolutely free hand on subject matter.
I sat down immediately and wrote "Fecundity Unlimited" my first article on the population problem. I sent it in on September 19, and it was taken at once.
The article appeared in the January 1958 issue of Venture.
The July, 1958 issue of Venture was the tenth and the last. The last issue contained Asimov's fourth science article written for it, "The Clash of Cymbals," about colliding galaxies.
To be sure, Asimov was writing science articles for a variety of other magazines, but he didn't have his own column.
On August 12, 1958, Asimov visited Bob Mills in New York. Mills asked Asimov if he would continue to write his science column for Fantasy and Science Fiction, and Asimov said yes. His first column to appear in F & SF was "Dust of Ages," in the November, 1958 issue...and he never missed another issue until he passed away. Originally the articles continued to be 1200 words, but by the fifth article they had settled at 4,000 words per essay. For each one, Asimov was to receive $100.
Bob Mills also gave Asimov his most well-known nickname, The Good Doctor.
It was in 1958 that Asimov quit (or was rather forced out) of his job as Associate Professor of the Boston University's School of Medicine, and began writing full time.
As Asimov had told one of the men involved in forcing him out of the school, it was his goal to become the greatest living science writer.