NASA runs various Centennial Challenges to encourage the development of technology it might find useful and to generally promote the state-of-the-art. There is a history in aerospace of challenges, such as the Orteig Prize that was won by Charles Lindbergh for crossing the Atlantic. A more recent example is the Ansari X Prize for repeated suborbital commercial spaceflights.
The full rules for the Sample Return Robot (SRR) Challenge are on the WPI web site. NASA summarizes the challenge as:
The Challenge requires demonstration of an autonomous robotic system to locate and collect a set of specific sample types from a large planetary analog area and then return the samples to the starting zone. The roving area will include open rolling terrain, granular medium, soft soils, and a variety of rocks, and immovable obstacles (trees, large rocks, water hazards, etc.) A pre-cached sample and several other samples will be located in smaller sampling zones within the larger roving area. Teams will be given aerial/geological/topographic maps with appropriate orbital resolution, including the location of the starting position and a pre-cached sample.
Since these robots are presumed to be on another planetary surface they cannot use GPS for localization nor a compass for bearing, as these are not available on other planets. An additional restriction, for safety, imposed is that the robots may not move faster than 2 meters per second. The competition area is specified as 80,000 square meters but the actual park area, a portion of Institute Park in Worcester, MA, is significantly smaller.
In addition to the robot there is a home beacon that is positioned at the back of the starting platform. It may contain a structure with size and weight limitations defined by the rules. The home beacon may not have moving components, in general, but may contain lights, computers or other static devices to aid the robot. The purpose of the home beacon, generally, is to provide a mechanism for the robot to sight and home on when returning to the starting platform. It is possible, for example, that a computer on the home beacon might contribute processing capabilities.
A comment on naming: the rules consider a robot to be the total material positioned on the starting platform at the start of a competition run. The rules allow for spawn which are portions of the original robot. In general, the competitors have taken to calling the individual spawn, rovers. My Team Mystic robot consists of a base that remains on the starting platform and three rovers that search for and return samples.