MarsMissionFactory receives the values for the name and rocket properties of mission, then supplies the remaining values to a builder instance. This narrows the properties required to make a new mission, while still using the builder interface.
This method of combining rather than modifying patterns is preferable in many use cases. Like more established library code, better-known patterns have better-defined contracts and more predictable behavior than custom ones. Their familiarity makes them easier for a newcomer to understand.
