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Space launch is the earliest part of a flight that reaches space. Space launch involves liftoff, when a rocket or other space launch vehicle leaves the ground at the start of a flight. Liftoff is of two main types: rocket launch, the current conventional method, non-rocket spacelaunch where other forms of propulsion are employed, including airbreathing jet engines or other kinds...

A POTD is an acronym for "Photo of the Day", "Picture of the Day", "Post of the Day" or "Poll of the Day". It is a term most commonly used by online digital photography communities as an honor to outstanding photos that are selected daily from among that community's membership. They can either be tagged as POTD or displayed in a special page on that site...