The book cover for this edition of Orbit Unlimited by Poul Anderson was created by John Schoenherr (July 5, 1935 – April 8, 2010). It depicts a crew of astronauts tethered to a spacecraft of some sort, near what appears to be an asteroid.
Here’s a closer look of the image without the bordering:
Schoenherr is perhaps best known for creating the original cover art for Dune, and he also did the art for The Illustrated Dune. Schoenherr did many other sci-fi covers, including Quest for the Future by A.E. Van Vogt and The Synthetic Man by Theodore Sturgeon. His work was also featured on many covers of Analog magazine.
Schoenherr’s work won him a handful of awards, including the Hugo Award for Best Professional Artist in 1965 and the Caldecott Medal in 1988 for his illustrations for Owl Moon. He was posthumously inducted into the Science Fiction and Fantasy Hall of Fame in 2015
