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 purposes.
The tier-scalable reconnaissance paradigm is also highly automated. Spaceborne orbiters command and control the airborne vehicles autonomously, and the airborne vehicles in turn command and control the ground-tier reconnaissance vehicles. This allows orbiters, airships, and rovers to act in a unified, controlled manner. A mission that uses this paradigm is also considered more survivable. Since the airborne and ground-tier vehicles can be quite inexpensive, even expendable, many such vehicles can be used collectively to explore numerous science targets with complementary suites of instruments. Even if one or more vehicles should fail, others are present to take up the slack and continue the mission.
Read more about this topic: Tier-Scalable Reconnaissance
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