[[File:WFink in 2007 5.jpg|thumb|250px|right|Tier-Scalable Reconnaissance:Three-tiered utilization on Mars. Tier 1: spaceborne orbiter; Tier 2: airborne blimps; Tier 3: ground-based rovers.]]Tier-scalable reconnaissance is the term for an approach to deploying and controlling vehicles in multiple areas of interest, such as in the exploration of planets or diverse regions on Earth. It is not a rigid or fixed paradigm, but is infinitely extensible. It uses hierarchical levels of oversight called tiers, each tier commanding or controlling the vehicles within the tier beneath it. The size of each tier can be scaled from one to many vehicles. Origination The tier-scalable reconnaissance paradigm was originated by Dr. Wolfgang Fink et al. at the California Institute of Technology. History Robotic planetary exploration missions typically use a single lander or rover. This is by design, driven primarily by safety and engineering constraints, at the expense of mission reliability and science return. Rovers are generally capable mobile platforms, but they are incapable of exploring multiple distant sites on a planetary surface. They are usually not used to explore potentially hazardous, scientifically interesting regions. At the other extreme, orbiting satellites have the benefit of a global perspective, but miss much surface detailed information. In either case, using a rover or orbiter, monitoring changing events on the surface is difficult, if not altogether impossible. Tier-scalable reconnaissance, on the other hand, distributes the burden of data gathering across different logical tiers. In this way, a mission is more distributed, goal-driven, and less constrained. And, because of the numerous vehicles in each tier, a mission is more survivable and more capable. Consider the following scenario: The vehicles in the spaceborne and airborne tiers have overhead perspectives at different scales and resolutions. They map out areas of interest and acquire terrain data, and then choose targets for visiting and sampling by the ground vehicles. The overhead perspective also allows the higher tiers to determine paths for safe passage of these vehicles to their targets. The ground-tier vehicles gather local data that complement the remote sensing data obtained by the spaceborne and airborne vehicles. In addition to the spaceborne and ground tiers, there may be several airborne tiers having vehicles such as balloons, blimps, and unmanned aerial vehicles (UAVs) at different altitudes. The tier-scalable reconnaissance paradigm is not limited to space, aerial, and ground applications but can be applied as well to water, subterranean, and ocean floor scenarios for scientific, commercial, or military