A CanSat is a simulation of a real satellite, that can fit inside the volume of a typical soft drink can. A CanSat has to position all the major subsystems found in a satellite, such as sensors, power and communication systems, into a small volume.
The CanSat is then launched to an altitude of a few hundred meters by a rocket or dropped from a drone or captive balloon, and then it carries out scientific experiments and achieves safe landing through a parachute.
CanSat requires the payload to fit inside the volume of a soda can (66mm diameter and 115mm height) and have a mass below 350g. Communication interface like Antenna and sensors has the option to be mounted externally.
The CanSat deployed from a small rocket or a drone reaches a certain height. This height varies depending on the need of the experiment.