We are developing the science and technology underpinnings for a fusion power source based on direct drive targets and krypton fluoride (KrF) lasers. Direct drive is chosen for its simplicity in the both the target physics and target fabrication, for its capability to achieve high energy gains, and for its unique potential to use a simple evacuated reaction chamber. KrF lasers have inherent physics advantages for achieving the robust high performance needed for the energy application. Gains greater than 140 are predicted with a relatively low laser energy of 1 MJ. Gains of 200 are predicted with energies of around 2 MJ. KrF also has engineering advantages (e.g. the gas the gas medium easier to cool than solid state laser media). Credible technologies have been identified for most of the key components for a power plant using direct laser drive, including: target fabrication, injection, and tracking; the optical system; the reaction chamber; and the major subsystems. In many cases these technologies have been demonstrated in small scale tests. This paper gives an overview of the progress in all these areas, and gives a more detailed discussion on solutions for the reaction chamber (including nano-engineered first wall and magnetic intervention). Further details can be found in the references listed at the end of this paper.