I am currently an Emeritus Professor of Aerospace Engineering. I have left the Penn State campus and relocated to Northern Virginia, where I continue to work in the aerospace industry.
Along with my co-author, Dr. Davide Conte, we have created the textbook, Interplanetary Astrodynamics. If you are interested in the book, you can find it at various places, such as Amazon.com.
We are compiling an errata for corrections and suggestions for the next edition. If you have suggestions, error corrections, or comments, please contact us at interplanetaryastrodynamics@gmail.com
Thanks,
David Spencer