U.S. Air Force 2nd Lt. Rebecca Esselstein pauses to

U.S. Air Force 2nd Lt. Rebecca Esselstein pauses to reflect on her longtime dream to become an astronaut, after finishing rowing team practice at the Wallingford Rowing Club, United Kingdom, March 23, 2017. Esselstein, who graduated at the top of her class from the Air Force academy, is also a record-setting athlete and Rhodes Scholar - pursuing a Ph.D. in Astrophysics from Oxford University. (U.S. Air Force photo by Airman 1st Class Zachary Bumpus/Released)