The Venture-class probe is the most commonly-used unmanned spacecraft. Whether they are launched from a capital ship, space station, or even from the surface of a planet, their function is the same: observe and transmit.
Their primary function is to maneuver to a destination and perform a set of scans. That data is encoded and transmitted back to whatever organization launched the probe.
In order to keep its mission-profile as diverse as possible, the Venture is constructed out of a set of modular components, allowing it to be customized for a variety of functions and obstacles. These modules include computer, transmitter, engine, maneuvering thrusters, atmosphere shield, landing legs, surface sampler, sensor suite, extended fuel tank, sensor mask, among many others. This has lead shipwrights to call it the "build-a-rocket"
Probes are most commonly used for military reconnaissance, planetary survey, or the study of spaceborn anomalies. Probes are not normally designed for a return-trip, and those that have been recovered are often barely functioning, since the modular design results in numerous points of failure.
Long distance probes are propelled by compact engines
Probes may reorient with maneuver modules, equipped with maneuvering thrusters and reaction-control wheels
Without shielding or armored hulls, probes may deploy a heat shield to protect itself during atmospheric entry
Probes may gracefully land on a surface by extending landing legs
Since most of a probe's operations require only electrical power, solar panels may be extended
Data may be transmitted by or to a probe with a communication module
Probes may be equipped with a wide variety of sensor equipment
Payload modules may be deployed to vacuum or a surface using cranes
Probes may traverse a surface environment using rover wheels