Today, Kerbal Space Program 2 will be receiving its biggest update yet, For Science! This update brings a brand-new game mode known as Exploration Mode, which adds progression and Science collection to the game through missions, an unlockable tech tree, and a campaign journey through the Kerbolar System. In addition to the new mode, there will also be new Science collection parts and a new interface for managing your Science collection. Atmospheric re-entry heating effects and thermal part behavior are also now available, and there are multiple quality of life improvements for the game in this update.
You can view the new gameplay trailer covering the update here:
Additional details can be found on the forum post here: https://forum.kerbalspaceprogram.com/topic/221185-for-science-ksp2s-first-milestone-update-is-available-now/