Science and History Expert interviewed frequently in space documentaries.International experience in relating science, engineering, astronomy, and wildlife to general audiences through classes, workshops, public speaking, television and documentary productions. Author of bestselling space history books. International keynote speaker at conferences.Media work on in-depth space stories for the Discovery Channel, History Channel, The Military Channel, from in-depth documentaries to news television and radio. International radio shows such as the BBC World Service, and NPR's All Things Considered. Undertook detailed work with NPR in preparing space stories. Undertook live reporting for radio from the 2017 total solar eclipse. In 2011, provided live space coverage for Al-Jazeera English: reaching 130 million homes, at the time it was the biggest global television audience.