This also means that having a streamlined shape is not really necessary out in space. After the streamlined rocket carries a spacecraft outside the Earth's atmosphere, its smooth outer shell is jettisoned. Solar panels and scientific instruments are unfolded. The Cassini spacecraft shown below is an example of a typical spacecraft shape. Sometimes finding one's way on Earth in a car with a road map can be difficult.
Scientists have to plan a manmade satellite's trip in advance.
They also have to be able to change its course during the trip. Every unmanned spacecraft has on board some type of guidance system. Spacecraft t also carry some sort of optical system for viewing stars. By measuring the angle between the spacecraft and several distant stars, trigonometry can be used to determine its location in space. When the spacecraft arrives at its destination planet, it must slow its speed to enter an orbit around the planet.