This is an online book that covers Astronomy of the Earth's Motion in Space, Newtonian Mechanics, The Sun, Spaceflight and Spacecraft, and a Math Refresher. It was originally intended for high schoolers, but the author has fleshed out many sections and some information is at the college level. The author also has a number of resources at this link: http://www.phy6.org/readfirst.htm
The appearance of any information in the Davidson Institute's Database does not imply an endorsement by, or any affiliation with, the Davidson Institute. All information presented is for informational purposes only and is solely the opinion of and the responsibility of the author. Although reasonable effort is made to present accurate information, the Davidson Institute makes no guarantees of any kind, including as to accuracy or completeness. Use of such information is at the sole risk of the reader.