Ben Bova, the legendary science fiction novelist and multiple Hugo Award winner, has died at 88, Tor.com reports. The cause of death was complications from pneumonia and a stroke related to Covid-19.

Bova, a Philadelphia native, began his career as a technical writer for the U.S. Naval Research Laboratory. He made his literary debut in 1959 with the novel The Star Conquerors and followed that up two years later with a nonfiction book, The Milky Way Galaxy.

Over the next decades, he wrote more than 100 books, including several installments in his Grand Tourseries of novels, which included Privateers, Return to Mars, and Titan. His most recent book, Uranus, was published in May, and a follow-up, Neptune, is slated for publication in 2021.

He won six Hugo Awards over his long career, all for editing the magazine Analog Science Fiction and Fact. He also edited the magazines Analog and Omni.

Admirers of Bova remembered the author on social media. Author Scott Edelman tweeted, “The first editor who ever took the time to send me a personal rejection letter—even though based on the story 17-year-old me submitted, I certainly didn’t deserve one—was…Ben Bova. I have always been grateful to him for that moment of grace. RIP.”

And editor John Joseph Adams wrote, “So sorry to hear of the death of Ben Bova. He was one of my major gateways to science fiction. I read his novel MARS and then tried to read *everything* of his—including his short fiction collections, which were probably the first short fiction I ever read. RIP.”

Michael Schaub is a Texas-based journalist and regular contributor to NPR.