 In the past five years, Earth observation has advanced beyond conventional space agency-based platforms to include sensing opportunities provided by CubeSats, unmanned aerial vehicles, UAVs, and smartphone technologies. Space agency efforts have brought forth well-known satellites such as Landsat and Grace, with costs typically of $1 billion per satellite and concept to launch timelines of two decades for new missions. Recently, the proliferation of smartphones has helped miniaturize sensors and energy requirements, enabling advances in CubeSats that can be launched by the dozens and provide ultra-high-resolution sensing of the Earth on a daily basis. Startup companies now operate more satellites in orbit than any space agency, at costs that are a fraction of. This article was authored by M. F. McCabe, M. Roddl, D. E. Alstorf and others.