Galaxy Map and Stars and Planets are two free apps in the Education category on both Apple App Store and Google Play.
The first one focuses more on the galactic scale (galaxies, nebulae, clusters, supernova remnants) and the second one takes a more in-depth look at star systems and exoplanets
You can explore the Solar System and land on terrestrial planets and moons in both of these apps.
A paid app exists in both app stores (called Galaxy Map - Stars and Planets) that combines the two free apps into a single one and has no ads and all in app purchases (+future purchases) included. The paid app is stripped of analytics, ads and payments libraries.
Stars and Planets is a beautifully crafted app with awe inspiring visuals within an exciting virtual universe. The sheer volume of information can excite even the most confident scientist and challenge them to expand their current understanding and curate their passion for all things ‘Space’.