
NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold answers questions from the audience after speaking about his time onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold answers questions from the audience after speaking about his time onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold answers questions from the audience after speaking about his time onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks to students in the Science, Discovery and the Universe Scholars Program about his time onboard the International Space Station, Thursday, May 2, 2019 at the University of Maryland in College Park, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks to students in the Science, Discovery and the Universe Scholars Program about his time onboard the International Space Station, Thursday, May 2, 2019 at the University of Maryland in College Park, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks to students in the Science, Discovery and the Universe Scholars Program about his time onboard the International Space Station, Thursday, May 2, 2019 at the University of Maryland in College Park, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks to students in the Science, Discovery and the Universe Scholars Program about his time onboard the International Space Station, Thursday, May 2, 2019 at the University of Maryland in College Park, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks to students in the Science, Discovery and the Universe Scholars Program about his time onboard the International Space Station, Thursday, May 2, 2019 at the University of Maryland in College Park, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks to students in the Science, Discovery and the Universe Scholars Program about his time onboard the International Space Station, Thursday, May 2, 2019 at the University of Maryland in College Park, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold presents a montage from his mission to Alan Peel, program director, and Erin Thompson, program associate, for the Science, Discovery and the Universe Scholars Program following his presentation to students, May 2, 2019 at the University of Maryland in College Park, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut and Maryland native Ricky Arnold signs a baseball for a young fan before the Tampa Bay Rays take on the Baltimore Orioles, Saturday, May 4, 2019 at Camden Yards in Baltimore, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut and Maryland native Ricky Arnold is seen on field before the Tampa Bay Rays take on the Baltimore Orioles, Saturday, May 4, 2019 at Camden Yards in Baltimore, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut and Maryland native Ricky Arnold takes a picture with a young fan before the Tampa Bay Rays take on the Baltimore Orioles, Saturday, May 4, 2019 at Camden Yards in Baltimore, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut and Maryland native Ricky Arnold signs an autograph before the Tampa Bay Rays take on the Baltimore Orioles, Saturday, May 4, 2019 at Camden Yards in Baltimore, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold presents Robert Gabrys, director of the Office fo STEM Engagement at NASA’s Goddard Space Flight Center, a montage from his mission onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold presents Robert Gabrys, director of the Office fo STEM Engagement at NASA’s Goddard Space Flight Center, a montage from his mission onboard the International Space Station, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold is introduced to speak about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold poses for a photo after presenting the Challenger Center with a montage of images from his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold poses for a photo with students after speaking with them about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold presents the Challenger Center with a montage of images from his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold poses for a photo with students after speaking with them about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold is seen during a talk about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold watches a timer while students conduct an experiment on effervescence, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the International Space Station (ISS), and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut and Maryland native Ricky Arnold is interviewed by Paul Mancano of MASN All Access before the Tampa Bay Rays take on the Baltimore Orioles, Saturday, May 4, 2019 at Camden Yards in Baltimore, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut and Maryland native Ricky Arnold talks with Baltimore Orioles shortstop Richie Martin before the Tampa Bay Rays take on the Baltimore Orioles, Saturday, May 4, 2019 at Camden Yards in Baltimore, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut and Maryland native Ricky Arnold is interviewed by Paul Mancano of MASN All Access before the Tampa Bay Rays take on the Baltimore Orioles, Saturday, May 4, 2019 at Camden Yards in Baltimore, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut and Maryland native Ricky Arnold is interviewed by Paul Mancano of MASN All Access before the Tampa Bay Rays take on the Baltimore Orioles, Saturday, May 4, 2019 at Camden Yards in Baltimore, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

A student shakes a glass of water with an Alka-Seltzer tab in it while conducting an experiment on effervescence, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. NASA astronaut Ricky Arnold helped them carry out the experiment which he also conducted during his 197 day mission onboard the International Space Station (ISS) during Expeditions 55/56. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold watches a timer while students conduct an experiment on effervescence, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the International Space Station (ISS), and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold watches a timer while students conduct an experiment on effervescence, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the International Space Station (ISS), and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut and Maryland native Ricky Arnold presents a montage of images from his mission and a Baltimore Orioles hat that was flown aboard the International Space Station to Baltimore Orioles manager Brandon Hyde before the Tampa Bay Rays take on the Baltimore Orioles, Saturday, May 4, 2019 at Camden Yards in Baltimore, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

NASA astronaut and Maryland native Ricky Arnold talks with Baltimore Orioles manager Brandon Hyde after presenting a montage of images from his mission and a Baltimore Orioles hat that was flown aboard the International Space Station before the Tampa Bay Rays take on the Baltimore Orioles, Saturday, May 4, 2019 at Camden Yards in Baltimore, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

A student holds up a glass of water with an Alka-Seltzer tab in it while conducting an experiment on effervescence, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. NASA astronaut Ricky Arnold helped them carry out the experiment which he also conducted during his 197 day mission onboard the International Space Station (ISS) during Expeditions 55/56. Photo Credit: (NASA/Aubrey Gemignani)

A student observes a glass of water with an Alka-Seltzer tab in it while conducting an experiment on effervescence, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. NASA astronaut Ricky Arnold helped them carry out the experiment which he also conducted during his 197 day mission onboard the International Space Station (ISS) during Expeditions 55/56. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold is interviewed for a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold speaks with Beth Wilson of Smithsonian National Air and Space Museum's Stem in 30 production, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold answers questions from the audience about his time onboard the International Space Station (ISS) during a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold answers questions from the audience about his time onboard the International Space Station (ISS) during a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold answers questions from the audience about his time onboard the International Space Station (ISS) during a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold answers questions from the audience about his time onboard the International Space Station (ISS) during a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold reacts as Marty Kelsey from Smithsonian National Air and Space Museum's production, Stem in 30, makes large bubbles behind him, while he speaks about his time onboard the International Space Station (ISS), Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold answers questions from the audience about his time onboard the International Space Station (ISS) during a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold answers questions from the audience about his time onboard the International Space Station (ISS) during a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold answers questions from the audience about his time onboard the International Space Station (ISS) during a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold answers questions from the audience about his time onboard the International Space Station (ISS) during a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold answers questions from the audience about his time onboard the International Space Station (ISS) during a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold, center, and Smithsonian National Air and Space Museum's Beth Wilson, left, and Marty Kelsey, right, react after a model volcano erupted with fire during a Stem in 30 segment, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold poses for a selfie with an audience member after speaking about his time onboard the International Space Station (ISS) during a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold answers questions from the audience about his time onboard the International Space Station (ISS) during a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold, center, and Smithsonian National Air and Space Museum's Beth Wilson, left, and Marty Kelsey, right, jump backwards as a model volcano erupts with fire during a Stem in 30 segment, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold answers questions from the audience about his time onboard the International Space Station (ISS) during a Smithsonian National Air and Space Museum production of Stem in 30, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

Robert Gabrys, director of the Office fo STEM Engagement at NASA’s Goddard Space Flight Center, introduces NASA astronaut Ricky Arnold prior to a presentation to employees, Thursday, May 2, 2019 at NASA’s Goddard Space Flight Center in Greenbelt, Md. During Arnold’s 197 days onboard the International Space Station, as part of Expeditions 55 and 56, he ventured outside the space station on three spacewalks in addition to conducting numerous experiments and educational downlink events. Photo Credit: (NASA/Joel Kowsky)

U.S. SECRETARY OF EDUCATION ARNE DUNCAN, ALONG WITH NASA ASTRONAUT RICKY ARNOLD AND OTHER GUESTS, ANSWER STUDENTS’ QUESTIONS DURING AN EDUCATIONAL TOWN HALL MEETING AT THE SPACE & ROCKET CENTER. THE SECRETARY’S VISIT WAS PART OF HIS TOUR TO PROMOTE EDUCATION, WITH STOPS IN GEORGIA, ALABAMA AND TENNESSEE

JSC2004-E-47576 (17 Aug. 2004) --- Richard R. (Ricky) Arnold II, mission specialist-educator candidate in NASA's 2004 class of astronauts.

Students are seen in the audience as NASA astronaut Ricky Arnold speaks about his time onboard the International Space Station (ISS) during Expeditions 55 and 56, Friday, May 3, 2019 at the Challenger Center in Lanham, MD. During Expedition 55/56, Arnold completed three spacewalks for a total of 19.5 hours outside the space station, and concluded his 197 day mission when he landed in a remote area near the town of Zhezkazgan, Kazakhstan in Oct. 2018. He also flew to the space station on shuttle mission STS-119 to deliver the final pair of power-generating solar array wings. Photo Credit: (NASA/Aubrey Gemignani)

iss055e004444 (March 24, 2018) --- NASA astronaut and Expedition 55 Flight Engineer Ricky Arnold rests inside the seven-windowed cupola as the International Space Station orbits above the south Atlantic Ocean.

Expedition 56 Flight Engineer Ricky Arnold of NASA rests outside the Soyuz Capsule after he, Expedition 56 Commander Drew Feustel of NASA, and Expedition 56 Flight Engineer and Soyuz Commander Oleg Artemyev of Roscosmos, landed in a remote area near the town of Zhezkazgan, Kazakhstan on Thursday, Oct. 4, 2018. Feustel, Arnold, and Artemyev are returning after 197 days in space where they served as members of the Expedition 55 and 56 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Expedition 56 Flight Engineer Ricky Arnold of NASA rests in a chair just minutes after he and Expedition 56 Commander Drew Feustel of NASA, and Expedition 56 Flight Engineer and Soyuz Commander Oleg Artemyev of Roscosmos landed in a remote area near the town of Zhezkazgan, Kazakhstan on Thursday, Oct. 4, 2018. Feustel, Arnold, and Artemyev are returning after 197 days in space where they served as members of the Expedition 55 and 56 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA astronaut Ricky Arnold, Portrait, Friday, June 28, 2019 at Michoud Assembly Facility, New Orleans, LA. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold, Portrait, Friday, June 28, 2019 at Michoud Assembly Facility, New Orleans, LA. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold, Portrait, Friday, June 28, 2019 at Michoud Assembly Facility, New Orleans, LA. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold, Portrait, Friday, June 28, 2019 at Michoud Assembly Facility, New Orleans, LA. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold, Portrait, Friday, June 28, 2019 at Michoud Assembly Facility, New Orleans, LA. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold, Portrait, Friday, June 28, 2019 at Michoud Assembly Facility, New Orleans, LA. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold, Portrait, Friday, June 28, 2019 at Michoud Assembly Facility, New Orleans, LA. Photo Credit: (NASA/Aubrey Gemignani)

NASA astronaut Ricky Arnold, Portrait, Friday, June 28, 2019 at Michoud Assembly Facility, New Orleans, LA. Photo Credit: (NASA/Aubrey Gemignani)

iss056e021157 (June 19, 2018) --- Expedition 56 Flight Engineer Ricky Arnold of NASA (foreground) performs maintenance inside the Combustion Integrated Rack to set up the Advanced Combustion via Microgravity Experiments (ACME), a series of five independent studies of gaseous flames. Expedition 56 Commander Drew Feustel of NASA is seen in the background.

iss056e097421 (July 19, 2018) --- NASA astronaut Ricky Arnold swabbed surfaces in the International Space Station to collect microbe samples. He then processed the microbial DNA using the Biomolecule Sequencer, a device that enables DNA sequencing in microgravity, to identify microbes able to survive in microgravity.

iss056e097438 (July 19, 2018) --- NASA astronaut Ricky Arnold swabbed surfaces in the International Space Station to collect microbe samples. He then processed the microbial DNA using the Biomolecule Sequencer, a device that enables DNA sequencing in microgravity, to identify microbes able to survive in microgravity.

iss056e097429 (July 19, 2018) --- NASA astronaut Ricky Arnold swabbed surfaces in the International Space Station to collect microbe samples. He then processed the microbial DNA using the Biomolecule Sequencer, a device that enables DNA sequencing in microgravity, to identify microbes able to survive in microgravity.

iss056e050302 (6/28/2018) --- Cosmonaut Oleg Artemyev and NASA astronaut Ricky Arnold during the Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES) maintenance session two, in the Japanese Experiment Module (JEM) Pressurized Module (JPM).

iss056e050304 (6/28/2018) --- Cosmonaut Oleg Artemyev and NASA astronaut Ricky Arnold during the Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES) maintenance session two, in the Japanese Experiment Module (JEM) Pressurized Module (JPM).

Expedition 56 Flight Engineer Ricky Arnold of NASA is helped out of the Soyuz MS-08 spacecraft just minutes after he, Expedition 56 Commander Drew Feustel of NASA, and Expedition 56 Flight Engineer and Soyuz Commander Oleg Artemyev of Roscosmos, landed in a remote area near the town of Zhezkazgan, Kazakhstan on Thursday, Oct. 4, 2018. Feustel, Arnold, and Artemyev are returning after 197 days in space where they served as members of the Expedition 55 and 56 crews onboard the International Space Station. Photo Credit: (NASA/Bill Ingalls)

Marty Kelsey of Smithsonian National Air and Space Museum's Stem in 30 production heats a panel of a spacecraft to demonstrate it's ability to stay cool during a segment with NASA astronaut Ricky Arnold, Friday, May 3, 2019 at Six Flags America theme park in Upper Marlboro, MD. Photo Credit: (NASA/Aubrey Gemignani)

Expedition 55 prime crew members Ricky Arnold of NASA, left, Oleg Artemyev of Roscosmos, center, and Drew Feustel of NASA, right, are seen in quarantine, behind glass, during a press conference, Tuesday, March 20, 2018 a the Cosmonaut Hotel in Baikonur, Kazakhstan. Expedition 55 Soyuz Commander Oleg Artemyev of Roscosmos, Ricky Arnold and Drew Feustel of NASA are scheduled to launch to the International Space Station aboard the Soyuz MS-08 spacecraft on Wednesday, March, 21. Photo Credit: (NASA/Joel Kowsky)

Expedition 55 flight engineer Ricky Arnold is seen in quarantine, behind glass, during a press conference, Tuesday, March 20, 2018 a the Cosmonaut Hotel in Baikonur, Kazakhstan. Arnold and his fellow Expedition 55 crew members Oleg Artemyev of Roscosmos and flight engineer Drew Feustel of NASA are scheduled to launch to the International Space Station aboard the Soyuz MS-08 spacecraft on Wednesday, March, 21. Photo Credit: (NASA/Joel Kowsky)

Expedition 55 flight engineer Ricky Arnold of NASA is seen in quarantine, behind glass, during a press conference, Tuesday, March 20, 2018 a the Cosmonaut Hotel in Baikonur, Kazakhstan. Arnold, Soyuz Commander Oleg Artemyev of Roscosmos, flight engineer Drew Feustel of NASA are scheduled to launch to the International Space Station aboard the Soyuz MS-08 spacecraft on Wednesday, March, 21. Photo Credit: (NASA/Joel Kowsky)

Expedition 55 flight engineer Ricky Arnold answers a question during a press conference, Tuesday, March 20, 2018 a the Cosmonaut Hotel in Baikonur, Kazakhstan. Arnold, Soyuz Commander Oleg Artemyev of Roscosmos, and flight engineer Drew Feustel of NASA are scheduled to launch to the International Space Station aboard the Soyuz MS-08 spacecraft on Wednesday, March, 21. Photo Credit: (NASA/Joel Kowsky)

NASA International Space Station Program Manager Kirk Shireman escorts Expedition 55 flight engineer Ricky Arnold of NASA as he prepares to board the Soyuz MS-08 spacecraft for launch, Wednesday, March 21, 2018 at the Baikonur Cosmodrome in Kazakhstan. Arnold and his crewmates Drew Feustel of NASA and Oleg Artemyev of Roscosmos will spend the next five months living and working aboard the International Space Station. Photo Credit: (NASA/Joel Kowsky)

Expedition 55 flight engineer Ricky Arnold of NASA performs the traditional door signing at the Cosmonaut Hotel prior to departing the hotel for launch on a Soyuz rocket with fellow crewmates Oleg Artemyev of Roscosmos and Drew Feustel of NASA, Wednesday, March 21, 2018 in Baikonur, Kazakhstan. Arnold, Artemyev, and Feustel will launch in their Soyuz MS-08 spacecraft to the International Space Station to begin a five month mission. Photo Credit: (NASA/Joel Kowsky)

Expedition 55 flight engineer Ricky Arnold of NASA waves farewell as he and Soyuz Commander Oleg Artemyev of Roscosmos and flight engineer Drew Feustel of NASA depart Building 254 for the launch pad a few hours before their launch, Wednesday, March 21, 2018 at the Baikonur Cosmodrome Kazakhstan. Launch of the Soyuz rocket will send Arnold, Artemyev, and Feustel on a five month mission aboard the International Space Station. Photo Credit: (NASA/Victor Zelentsov)

Expedition 55 flight engineer Ricky Arnold of NASA is seen during the State Commission meeting to approve the Soyuz launch of Expedition 55 to the International Space Station, Tuesday, March 20, 2018. Arnold, Soyuz Commander Oleg Artemyev of Roscosmos, and flight engineer Drew Feustel of NASA are scheduled to launch to the International Space Station aboard the Soyuz MS-08 spacecraft on Wednesday, March, 21. Photo Credit: (NASA/Joel Kowsky)