Small satellite missions can be achieved by using different approaches and methods. One possible approach takes full advantage of ongoing technology development efforts leading to miniaturization of engineering components, development of micro-technologies for sensors and instruments, and others which allow the design of dedicated, well-focused Earth observation missions. Application Specific Integrated Micro-instruments (ASIM) are enabled by Micro-Electro-Mechanical Systems (MEMS) using microelectronics for data processing, signal conditioning, power conditioning, and communications. These micro- and nano-technologies have led to the concepts of nano- and pico-satellites, constructed by stacking wafer-scale ASIMs together with solar cells and antennas on the exterior surface. Space sensor webs are one outcrop of this technology. Further milestones in the cost-effective Earth observation mission developments are the availability and improvement of small launchers, the development of small ground station networks connected with rapid and cost-effective data distribution methods, and cost-effective management and quality assurance procedures. The paper is based on the outcomes of the study “Cost.Effective Earth Observation Missons” by an international team of experts in the framework of the International Academy of Astronautics [1]. It deals with general trends in the field of small satellite missions for Earth observation as well as trends specific for the segments of a misson: space segment, launch segment, ground segment. Visions are given for their further developments in the direction of improvement of cost-effectiveness of Earth observation missions