There were plenty of space games on the Atari 2600. It was a futuristic device when it came out, and back then the future meant space. Solaris was one of the most ambitious of them, with flight simulator controls and an entire galaxy to explore. Alien fleets moved around its map, eventually attacking human worlds that had to be defended before they were destroyed, or the fleets could be caught in space and fought there.
On the map screen you selected a destination and then leapt into hyperwarp, but first you had to line up the trajectory by keeping your shivering, twitching ship synced up with a ghost of itself on the centre of the screen. It was weird. Solaris treated space travel as an unsettling thing. If you didn't save a planet in time it got blown up and the entire quadrant became a Red Zone, where the screen flashed with disorientating lightning and all flight controls were reversed. There were 'corridors' blocking some quadrant exits in which you hurtled through a tunnel and had to fly over a key without which you'd hit a wall and explode, and minefields of spinning buoys.
Like the Stanislaw Lem novel with which it shares a name, Solaris makes space seem eerie and unnatural, a place humans should not be. For a game that's all of 16 kilobytes that's a hell of an achievement.