It is a spacecraft that is designed to travel to a distant planet and enter into its orbit. It must be equipped with propulsive capability and must be able to decelerate at any moment to enter into the orbit. The spacecraft's production of electrical power can be cut off during solar occultation. (Occultation is the blockage of light due to the intervention of another object) Thus it must be designed to withstand thermal variations. Earth occultation's may also occur cutting the uplink and downlink communication with earth. They are used for the second phase of solar exploration thus enabling in-depth study of various planets.
Eg- gallileo, which entered Jupiter orbit