JPL Director Michael Watkins, left, explains to U.S. Vice President Mike Pence, daughter of Mike Pence, Charlotte Pence, and wife of Mike Pence, Karen Pence the progress for the Mars 2020 mission while inside the Spacecraft Assembly Facility (SAF) during a tour of NASA's Jet Propulsion Laboratory, Saturday, April 28, 2018 in Pasadena, California. Photo Credit: (NASA/Bill Ingalls)

U.S. Vice President Mike Pence, his wife Karen, and their daughter Charlotte are shown how to send a command to the Curiosity rover on Mars by Mars Curiosity Mission ACE Walt Hoffman during a tour of NASA's Jet Propulsion Laboratory, Saturday, April 28, 2018 in Pasadena, California. Hoffman asked Charlotte Pence if she would do the honors of sending the command to the rover. Photo Credit: (NASA/Bill Ingalls)

U.S. Vice President Mike Pence, 2nd from left, his wife Karen, and daughter Charlotte are given a tour of NASA's Jet Propulsion Laboratory by JPL Director Michael Watkins, Saturday, April 28, 2018 in Pasadena, California. Photo Credit: (NASA/Bill Ingalls)

Second Lady Karen Pence gives commands to a rover nicknamed "Scarecrow" as NASA Mars Exploration Manager Li Fuk, left, Mars Curiosity Engineering Operations Team Chief Megan Lin, Vice President Mike Pence, daughter of Mike Pence, Charlotte Pence, and JPL Director Michael Watkins, right, look on, Saturday, April 28, 2018 in Pasadena, California. Scarecrow is used to test mobility of rovers on Mars. Photo Credit: (NASA/Bill Ingalls)

U.S. Vice President Mike Pence, his wife Karen, and their daughter Charlotte shake hands with Mars Curiosity Mission ACE Walt Hoffman, right, during a tour of NASA's Jet Propulsion Laboratory, Saturday, April 28, 2018 in Pasadena, California. Photo Credit: (NASA/Bill Ingalls)

U.S. Vice President Mike Pence gives commands to a rover nicknamed "Scarecrow" as NASA Mars Exploration Manager Li Fuk, left, Mars Curiosity Engineering Operations Team Chief Megan Lin, JPL Director Michael Watkins, and daughter of Mike Pence, Charlotte Pence, right, look on, Saturday, April 28, 2018 in Pasadena, California. Scarecrow is used to test mobility of rovers on Mars. Photo Credit: (NASA/Bill Ingalls)

JPL Director Michael Watkins, left, explains the history of NASA's Jet Propulsion Laboratory and the use of the Mission Support Area to Vice President Mike Pence, seated 4th from left, during a tour of JPL, Saturday, April 28, 2018 in Pasadena, California. Joining the Vice President was, JPL Distinguished Visiting Scientist and Spouse of UAG Chairman James Ellis, Elisabeth Pate-Cornell, left, UAG Chairman, Admiral (Ret) James Ellis, Executive Director of the National Space Council Scott Pace, wife of Mike Pence, Karen Pence, daughter of Mike Pence, Charlotte Pence, and JPL Deputy Director Lt. Gen. (Ret) Larry James. Photo Credit: (NASA/Bill Ingalls)

U.S. Vice President Mike Pence, 3rd from right, tours NASA's Jet Propulsion Laboratory along with his wife Karen, and daughter Charlotte, Saturday, April 28, 2018 in Pasadena, California. Joining the Vice President t and his family on the tour are: UAG Chairman, Admiral (Ret) James Ellis , left, JPL Distinguished Visiting Scientist and Spouse of UAG Chairman James Ellis, Elisabeth Pate-Cornell, behind Mrs. Pence, California Institute of Technology President Thomas Rosenbaum, JPL Director Michael Watkins, and JPL Deputy Director Lt. Gen. (Ret) Larry James, right. Photo Credit: (NASA/Bill Ingalls)

JPL Director Michael Watkins, standing, explains the history of NASA's Jet Propulsion Laboratory and the use of the Mission Support Area to Vice President Mike Pence, seated next to his wife Karen and daughter Charlotte Pence, during a tour of JPL, Saturday, April 28, 2018 in Pasadena, California. Joining the Vice President was, JPL Distinguished Visiting Scientist and Spouse of UAG Chairman James Ellis, Elisabeth Pate-Cornell, left, UAG Chairman, Admiral (Ret) James Ellis, JPL Deputy Director Lt. Gen. (Ret) Larry James, and California Institute of Technology President Thomas Rosenbaum. Photo Credit: (NASA/Bill Ingalls)

U.S. Vice President Mike Pence, 3rd from left, his wife Karen, and their daughter Charlotte meet with JPL Director Michael Watkins, and Mars Curiosity Mission ACE Walt Hoffman, right, during a tour of NASA's Jet Propulsion Laboratory, Saturday, April 28, 2018 in Pasadena, California. Photo Credit: (NASA/Bill Ingalls)

U.S. Vice President Mike Pence, 5th from left, joined by his wife Karen Pence, left, and daughter Charlotte Pence. 2nd from left, view the Vehicle System Test Bed (VSTB) rover in the Mars Yard during a tour of NASA's Jet Propulsion Laboratory, Saturday, April 28, 2018 in Pasadena, California. NASA Mars Exploration Manager Li Fuk, 2nd from left, JPL Director Michael Watkins, Mars Curiosity Engineering Operations Team Chief Megan Lin, and MSL Engineer Sean McGill, right, helped explain to the Vice President and his family how they use these test rovers. Photo Credit: (NASA/Bill Ingalls)

U.S. Vice President Mike Pence can be seen with his wife Karen Pence as they toured NASA's Jet Propulsion Laboratory, Saturday, April 28, 2018 in Pasadena, California. The vice President was also joined by his daughter Charlotte Pence, JPL Distinguished Visiting Scientist and Spouse of UAG Chairman James Ellis, Elisabeth Pate-Cornell , UAG Chairman, Admiral (Ret) James Ellis , Executive Director of the National Space Council Scott Pace, JPL Deputy Director Lt. Gen. (Ret) Larry James, and California Institute of Technology President Thomas Rosenbaum. Photo Credit: (NASA/Bill Ingalls)

U.S. Vice President Mike Pence, 2nd from right, is shown the Mars 2020 spacecraft descent stage from inside the Spacecraft Assembly Facility (SAF) by JPL Director Michael Watkins, to the Vice President's left, and NASA Mars Exploration Manager Li Fuk at NASA's Jet Propulsion Laboratory, Saturday, April 28, 2018 in Pasadena, California. Mars 2020 is a Mars rover mission by NASA's Mars Exploration Program with a planned launch in 2020. Photo Credit: (NASA/Bill Ingalls)