Elon Musk secretly ordered his engineers to turn off his company's Starlink satellite communications network near the Crimean coast last year to disrupt a Ukrainian sneak attack on the Russian naval fleet, according to an excerpt adapted from Walter Isaacson's new biography of the eccentric billionaire titled "Elon Musk."

As Ukrainian submarine drones strapped with explosives approached the Russian fleet, they "lost connectivity and washed ashore harmlessly," Isaacson writes.

Musk's decision, which left Ukrainian officials begging him to turn the satellites back on, was driven by an acute fear that Russia would respond to a Ukrainian attack on Crimea with nuclear weapons, a fear driven home by Musk's conversations with senior Russian officials, according to Isaacson, whose new book is set to be released by Simon & Schuster on September 12.

Musk's concerns over a "mini-Pearl Harbor" as he put it, did not come to pass in Crimea. But the episode reveals the unique position Musk found himself in as the war in Ukraine unfolded. Whether intended or not, he had become a power broker US officials couldn't ignore.

The new book from Isaacson, the author of acclaimed biographies of Steve Jobs and Albert Einstein, provides fresh insights into Musk and how his existential dread of sparking a wider war drove him to spurn Ukrainian requests for Starlink systems they could use to attack the Russians.