Jonathan McDowell, an astrophysicist, recently spoke about the "Dawn of the Space Age" at the Library of Congress. He told the story of the first five years of the Space Age, from 1957 to 1961, using once-secret materials declassified in the 1990s by the United States and the former Soviet Union.

McDowell discussed questions such as: Where does space begin? Whose rockets were really more reliable? Was the contemporary perception of a Soviet lead correct? Who invented the "apogee kick motor" (a rocket motor that sends the craft into orbit)?

McDowell is an astrophysicist in the Science Data Systems Planning Group in the Harvard-Smithsonian Center for Astrophysics, which is based at Harvard University. He received a degree in mathematics from Churchill College, University of Cambridge, and a doctorate from the Institute of Astronomy at Cambridge.

McDowell writes a monthly column for Sky and Telescope Magazine and a weekly e-mail-distributed newsletter, "Jonathan's Space Report."