Advances in sensor technology are needed to meet this challenge.  Here we see the current generation of US polar-orbiting environmental satellites (POES), which carry a variety of conventional sensors. The POES instruments depend primarily on passively sensing natural atmospheric emissions or reflected sunlight in the visibile, infrared and microwave bands. While these methods perform well on clear, benign days, they can degrade where weather is acting up. Infrared radiation, for example, does not penetrate heavy clouds.