  Space exploration is of paramount importance to advancing fundamental science
and providing global services, such as navigation and communications. However,
today's space missions are hindered by limitations of existing propulsion
technologies. Here, we examine the use of laser-driven light-sailing for agile
Earth orbital maneuvering and for fast-transit exploration of the solar system
and interstellar medium. We show that laser propulsion becomes practical at
laser powers around 100 kW and laser array sizes ~1 m, which are feasible in
the near term. Our analysis indicates that lightweight (1 g - 100 g)
wafer-scale (~10 cm) spacecraft may be propelled by lasers to orbits that are
beyond the reach of current systems. We further compare our findings with
previous interstellar laser propulsion studies, and show that our approach is
less constricting on laser architecture and spacecraft photonic design. We
discuss material requirements and photonic designs. We show that light-sails
made of silicon nitride and boron nitride are particularly well suited for
discussed applications. Our architecture may pave the way to ubiquitous Earth
orbital networks and fast-transit low-cost missions across the solar system.
