According to its website, MapQuest gathers its satellite image data from third-party provider i-cubed (Information Integration & Imaging), LLC. According to the website, i-cubed collects its satellite imagery from a variety of Earth observation satellites, including DigitalGlobe's Worldview 1, 2 and 3 and Airbus's Pleiades.
I-cubed describes itself as providing "vendor-agnostic" geospatial data and information management for commercial and government clients. It maintains a list of satellites and spec data that can be utilized in providing imagery for MapQuest. The satellites currently providing services for i-cubed are Digitalglobe's Quickbird, FORMOSAT-2, IKONOS, GeoEye-1 and Worldview 1, 2 and 3, as well as Airbus's Pleiades 1 and SPOT 4, 5, 6 and 7, as of 2015.