Robert Forward has died.

He was a brilliant man, a titan in science, technology and science fiction. Probably no single man came up with and fleshed out more concepts that may ultimately result in our visiting other solar systems.

He was the king of anti-matter propulsion, but he also developed concepts for star travel via light sail. In addition, in more mundane matters (relating only to travel in our own solar system), he was a leading light on the care and use of tethers.

I have many (literally) vivid memories of him, particularly of his sartorial oddness. He was a man quite comfortable in a rainbow hued vest amidst a group of gray suits and ties. His ideas stood out in much the same way. I deeply regret that he didn’t have the opportunity to see many of his ideas come to fruition.