The class-5 probe or level-5 probe was a medium-range probe carried aboard Federation starships and used as a reconnaissance probe and for planetary analysis. It was equipped with visual sensors, as well as sensors that could detect the chemical contents of an atmosphere and geological sensors. It maintained orbit with impulse thrusters. The probe had an operational life span of over two hundred years, by which time its thrusters would permanently degrade. (VOY: "Blink of an Eye")
In 2376, Chakotay ordered B'Elanna Torres to modify a class-5 probe to scan the geography and take pictures, every ten microseconds, of Kelemane's planet. USS Voyager gathered information about the planet when the ship was trapped in orbit above the planet. Data returned by the probe indicated that the civilization on the surface had advanced to an industrial level. It also reported the frequency of the seismic disturbances caused by Voyager's presence. (VOY: "Blink of an Eye")
The Star Trek: The Next Generation Technical Manual (p. 117) provides more detailed information on the class-5 medium range reconnaissance probe. It is powered by a small matter-antimatter engine, providing power for extended duration sublight and a limited duration warp travel at a maximum of warp factor 2 speed. It has a range of 43 billion kilometers and is designed with planetary atmosphere entry and soft landing capability. The probe has low observability hull materials and coating. Its sensors are designed for extended passive data-gathering and recording. The probe is designed to function as a full autonomous craft in executing its mission and returning home. Telemetry includes 6,320 channels at 2.5 megawatts. The probe can also be modified for tactical applications with the addition of a customized sensor countermeasure package.