Short answer: Yes, but officially deprecated.
The official SpaceEngine website (spaceengine.org) now redirects all new users to the Steam store page for the paid version. However, the developers have left the legacy 0.990 version available for download as a free "demo." You cannot get the latest 0.990 features (like volumetric accretion disks) for free, but the base 0.990 build is still legally downloadable. space engine 0990 download free upd
Search engines are flooded with fake "Space Engine 0990 download free upd" links. These often appear on domains like: Short answer: Yes, but officially deprecated
These are 99.9% malicious. They typically host: These are 99
Red flags to watch for:
Look for a filename containing 0_990_39 or 0_990_40. This is the final "upd" (update) before the Steam migration.