At present, after purchasing the Apollo Lunar Missions, the feature is only available from the In-App Purchases page from within SkySafari Settings. By contrast, the Interactive H-R Diagram option, subsequent to purchase, becomes visible as an explicit item within the main Settings list.
Exposing the Apollo Lunar Missions via the In- App Purchases page (View Missions), within Settings, introduces a fundamental problem; for devices where in-App purchases are intentionally prohibited within ScreenTime restrictions, the purchased Apollo Missions are not accessible. The only workaround is to remove the system-wide purchasing restriction.
Please consider moving the purchased Apollo Lunar Missions from the In-App Settings page - and expose the option, after purchase, in the same manner as the Interactive H-R Diagram.