1) Early rockets in ancient Greece and China used steam or gunpowder for propulsion.
2) In the 15th century, improvements were made to rocket design and gunpowder mixtures which increased rocket range.
3) In the late 19th century, rockets were used experimentally for applications like delivering mail and harpooning whales.
4) Pioneers like Robert Goddard and Wernher von Braun experimented with liquid-fueled rockets in the early 20th century and helped enable the beginning of the Space Race between the US and USSR after World War II.