High angular resolution imaging at low frequencies (below ∼ 10 MHz) requires observations from above the ionosphere. A radio interferometer array in space will be able to open new vistas in solar, terrestrial, galactic, and extragalactic astrophysics. A space-based interferometer could image and track transient disturbances in the solar corona and interplanetary medium - a new capability which is crucial for understanding many aspects of solar-terrestrial interaction and space weather. It could also produce the first sensitive, high-angular-resolution radio surveys of the entire sky at low frequencies. The radio sky will look entirely different below 10-30 MHz because new emission and absorption processes become dominant at these frequencies. As a result, low frequency surveys from space will provide a fundamentally new view of the universe and an extraordinarily large and varied science return.