* The 20th century saw the beginnings of space exploration, which was enabled by the development of new and powerful rocket propulsion systems that could lift heavy payloads into space, and give such payloads the ability to control themselves once they were in space. The development of spaceflight propulsion systems continues in the 21st century, with new technologies that offer improved capabilities. This document provides an overview of spaceflight propulsion systems. It is also available in a downloadable archive, formatted in HTML, for reading on a tablet or other viewer.
Those who don't have the time to wade through a detail document may prefer the shorter A Spaceflight Propulsion Primer instead.