Cosmologist, Professor of Physics & Astrophysical Sciences at Princeton and Author of "Our Universe: An Astronomer's Guide"
Speleologist; Associate Director of the National Cave and Karst Research Institute
NASA Aerospace Engineer & Mission Lead for the Mars Curiosity Rover; STEM Education Advocate
Former NASA Astronaut; Educator & Earth Scientist
Research Scientist; NASA Goddard Spaceflight Center
Former NASA Astronaut & First African-American In Space