NASA Administrator Jim Bridenstine, left, meets with NASA astronaut Randy Bresnik, Wednesday, May 9, 2018 at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

Students listen as NASA astronaut Randy Bresnik and ESA astronaut Paolo Nespoli speak about their time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

Students listen as NASA astronaut Randy Bresnik and ESA astronaut Paolo Nespoli speak about their time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

A student raises her hand to ask a question after NASA astronaut Randy Bresnik and ESA astronaut Paolo Nespoli spoke about their time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

Students listen as NASA astronaut Randy Bresnik and ESA astronaut Paolo Nespoli speak about their time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik's wife Rebecca and her friend Shiela present the Washington School for Girls a necklace that was flown in space onboard the International Space Station, Friday, May 11, 2018 at the Washington School for Girls in Washington. The necklace is a graduation gift for each student when they complete 8th grade. Photo Credit: (NASA/Aubrey Gemignani)

ESA astronaut Paolo Nespoli speaks about his time onboard the International Space Station during expeditions 52/53, Thursday, May 10, 2018 at the Smithsonian National Air and Space Museum in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, left, and ESA astronaut Paolo Nespoli speak about their time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, right, and ESA astronaut Paolo Nespoli, left, speak about their time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, left, and ESA astronaut Paolo Nespoli answer questions about their time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik speaks about his time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, left, and ESA astronaut Paolo Nespoli speak about their time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

ESA astronaut Paolo Nespoli speaks to an audience member during a break about his time onboard the International Space Station, Thursday, May 10, 2018 at the Smithsonian National Air and Space Museum in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik speaks about his time onboard the International Space Station during expeditions 52/53, Thursday, May 10, 2018 at the Smithsonian National Air and Space Museum in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik speaks about his time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, right, and his friend Shiela, center, present the principle of the school Dr. Beth Reaves, with a montage of images and items from Expedition 53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, left, and ESA astronaut Paolo Nespoli answer questions about their time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

ESA astronaut Paolo Nespoli gives a patch to a teacher for Teacher Appreciation Week after speaking about his time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

ESA astronaut Paolo Nespoli speaks about his time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

A student asks NASA astronaut Randy Bresnik a question about his time onboard the International Space Station, Thursday, May 10, 2018 at the Smithsonian National Air and Space Museum in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, left, and ESA astronaut Paolo Nespoli answer questions about their time onboard the International Space Station during expeditions 52/53, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA Administrator Jim Bridenstine, center, meets with ESA astronaut Paolo Nespoli, left, and NASA astronaut Randy Bresnik, Wednesday, May 9, 2018 at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Jim Bridenstine, left, makes a photograph with NASA astronaut Randy Bresnik, center, and ESA astronaut Paolo Nespoli, Wednesday, May 9, 2018 at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Jim Bridenstine meets with NASA astronaut Randy Bresnik, right, Bresnik's wife Rebecca and ESA astronaut Paolo Nespoli, Wednesday, May 9, 2018 at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Jim Bridenstine, left, meets with NASA astronaut Randy Bresnik, Bresnik's wife Rebecca, and ESA astronaut Paolo Nespoli, right, Wednesday, May 9, 2018 at NASA Headquarters in Washington. Photo Credit: (NASA/Bill Ingalls)

NASA astronaut Randy Bresnik, left, and ESA astronaut Paolo Nespoli, right, speak about their time onboard the International Space Station during expeditions 52/53, Thursday, May 10, 2018 at the Smithsonian National Air and Space Museum in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, left, and ESA astronaut Paolo Nespoli, right, speak about their time onboard the International Space Station during expeditions 52/53, Thursday, May 10, 2018 at the Smithsonian National Air and Space Museum in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, second from right, and ESA astronaut Paolo Nespoli, right, speak about their time onboard the International Space Station during expeditions 52/53, Thursday, May 10, 2018 at the Smithsonian National Air and Space Museum in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik and ESA astronaut Paolo Nespoli speak about their time onboard the International Space Station, Friday, May 11, 2018 at the Washington School for Girls in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, right, and ESA astronaut Paolo Nespoli, left, speak about their time onboard the International Space Station during expeditions 52/53, Thursday, May 10, 2018 at the Smithsonian National Air and Space Museum in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, left, and ESA astronaut Paolo Nespoli, right, speak about their time onboard the International Space Station during expeditions 52/53, Thursday, May 10, 2018 at the Smithsonian National Air and Space Museum in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, second from right, and ESA astronaut Paolo Nespoli, right, are introduced by STEM in 30's Marty Kelsey before speaking about their time onboard the International Space Station during expeditions 52/53, Thursday, May 10, 2018 at the Smithsonian National Air and Space Museum in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, left, and ESA astronaut Paolo Nespoli, right, speak about their time onboard the International Space Station during expeditions 52/53, Thursday, May 10, 2018 at the Smithsonian National Air and Space Museum in Washington. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Randy Bresnik, left, and ESA astronaut Paolo Nespoli, right, present Marty Kelsey, second from right, and Beth Wilson, of STEM in 30 with their sticker that flew in space onboard the International Space Station during expeditions 52/53, Thursday, May 10, 2018 at the Smithsonian National Air and Space Museum in Washington. Photo Credit: (NASA/Aubrey Gemignani)