GeoSync

Completely free: no in-app purchases (despite what it says above)

Maintain your satellite's orbit above each planet of the solar system! This new offering from TBA Games combines science with fun, challenging gameplay.

-- Avoid rocks, debris, and radiation hazards
-- switch between ion and hull thruster modes to maneuver
-- collect and transmit data
-- upgrade your satellite

Geosync contains:

-- over 70 levels of increasing difficulty
-- all nine planets (and we're counting Pluto!)
-- original soundtrack
-- Free satellite skins: just for fun, play as famous spacecraft including Sputnik, Hubble, and Voyage

If you enjoy this game, please rate!