By both dramatically reducing spacecraft cost and size, along with development schedule, the proposed Hummingbird spacecraft provides the opportunity to meet multiple Earth science and solar system exploration mission needs. Missions being considered for the Hummingbird spacecraft, constellations, or clusters include GPS Radio Occultation (GPSRO), Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS), Global Atmospheric Composition Mission (GACM), Gravity Recovery and Climate Experiment (GRACE-II), Comet Surface Sample Return (CSSR), Trojan Tour and Rendezvous (TTR), and Lunar Geophysical Network (LGN). All of these missions could benefit by having constellations of satellites, satellites able to orbit at much lower altitudes, or a combination of the two. For example, the GPSRO mission could significantly increase the number of satellites in the constellation from the 6 currently being planned and still end up with an overall mission cost much less than the planned $150M. The CSSR, TTR, and LGN missions all would benefit from the very large delta-V capability that is inherent in the current NanoEye spacecraft that can be modified to accommodate the different needs of these 3 missions, which is especially easy relative to adding delta-V capability at low non-recurring cost. The principal non-NASA Hummingbird application is for military missions, with additional applications for weather monitoring, disaster monitoring and news photography, that provides rapid revisit opportunities and real-time or near real time viewing of the Earth's surface through the use of Hummingbird constellations, in particular. Weather monitoring represents a major application area that could benefit greatly from the low cost aspect of Hummingbird that would allow large constellations of spacecraft focused on data collection of selected latitude ranges of interest. Approximately 30 satellites would provide repeat coverage of selected regions approximately every 10 minutes 24 hours per day, seven days per week, and both during the day and at night. In addition, even when not over a specific area of interest, weather data could still be collected for use by others.