Russian security officers inspect the tracks before the Soyuz rocket is rolled out to the launch pad on Monday, April 17, 2017 at the Baikonur Cosmodrome in Kazakhstan. The Soyuz MS-04 spacecraft, scheduled to launch April 20 Baikonur time, will carry Expedition 51 Soyuz Commander Fyodor Yurchikhin of Roscosmos and Flight Engineer Jack Fischer of NASA into orbit to begin their four and a half month mission on the International Space Station. Photo Credit: (NASA/Aubrey Gemignani)

The moon is seen as Russian security officers inspect the tracks before the Soyuz rocket is rolled out to the launch pad on Monday, April 17, 2017 at the Baikonur Cosmodrome in Kazakhstan. The Soyuz MS-04 spacecraft, scheduled to launch April 20 Baikonur time, will carry Expedition 51 Soyuz Commander Fyodor Yurchikhin of Roscosmos and Flight Engineer Jack Fischer of NASA into orbit to begin their four and a half month mission on the International Space Station. Photo Credit: (NASA/Aubrey Gemignani)

A Russian security officer is seen as the Soyuz MS-04 spacecraft is rolled out to the launch pad by train on Monday, April 17, 2017 at the Baikonur Cosmodrome in Kazakhstan. Launch of the Soyuz rocket is scheduled for April 20 and will carry Expedition 51 Soyuz Commander Fyodor Yurchikhin of Roscosmos and Flight Engineer Jack Fischer of NASA into orbit to begin their four and a half month mission on the International Space Station.Photo Credit: (NASA/Aubrey Gemignani)

A Russian security patrol officer stands watch along the railroad tracks as the Soyuz rocket is rolled out to the launch pad Monday, Sept. 28, 2009 at the Baikonur Cosmodrome in Kazakhstan. The Soyuz is scheduled to launch the crew of Expedition 21 and a spaceflight participant on Sept. 30, 2009. Photo Credit: (NASA/Bill Ingalls)

KAZAKHSTAN -- Russian security officers walk along the railroad tracks as the Soyuz rocket is rolled out to the launch pad Monday, Sept. 28, 2009 at the Baikonur Cosmodrome in Kazakhstan. The Soyuz is scheduled to launch the crew of Expedition 21 and a spaceflight participant on Sept. 30, 2009. Photo Credit: (NASA/Bill Ingalls)

KAZAKHSTAN -- Russian security officers walk along the railroad tracks as the Soyuz rocket is rolled out to the launch pad Monday, Sept. 28, 2009 at the Baikonur Cosmodrome in Kazakhstan. The Soyuz is scheduled to launch the crew of Expedition 21 and a spaceflight participant on Sept. 30, 2009. Photo Credit: (NASA/Bill Ingalls)

Russian security officers walk along the railroad tracks out to the launch pad Monday, Nov. 11, 2011 at the Baikonur Cosmodrome in Kazakhstan. The Soyuz TMA-22 is scheduled to launch the crew of Expedition 29 on November 14. Photo Credit: (NASA/Carla Cioffi)

Russian security officers walk along the railroad tracks as the Soyuz rocket is rolled out to the launch pad Monday, Sept. 28, 2009 at the Baikonur Cosmodrome in Kazakhstan. The Soyuz is scheduled to launch the crew of Expedition 21 and a spaceflight participant on Sept. 30, 2009. Photo Credit: (NASA/Bill Ingalls)

A Russian security officer stands guard as the Soyuz TMA-18 spacecraft is rolled out by train to the launch pad at the Baikonur Cosmodrome, Kazakhstan, Wednesday, March, 31, 2010. The launch of the Soyuz spacecraft with Expedition 23 Soyuz Commander Alexander Skvortsov of Russia, Flight Engineer Mikhail Kornienko of Russia, and NASA Flight Engineer Tracy Caldwell Dyson is scheduled for Friday, April 2, 2010 at 10:04 a.m. Kazakhstan time. Photo Credit (NASA/Bill Ingalls)

Russian security officers and their dog patrol the railroad track ahead of the Soyuz TMA-18 spacecraft as it is rolled out by train to the launch pad at the Baikonur Cosmodrome, Kazakhstan, Wednesday, March, 31, 2010. The launch of the Soyuz spacecraft with Expedition 23 Soyuz Commander Alexander Skvortsov of Russia, Flight Engineer Mikhail Kornienko of Russia, and NASA Flight Engineer Tracy Caldwell Dyson is scheduled for Friday, April 2, 2010 at 10:04 a.m. Kazakhstan time. Photo Credit (NASA/Bill Ingalls)

A Russian security officer stands guard as the Soyuz TMA-18 spacecraft is rolled out by train to the launch pad at the Baikonur Cosmodrome, Kazakhstan, Wednesday, March, 31, 2010. The launch of the Soyuz spacecraft with Expedition 23 Soyuz Commander Alexander Skvortsov of Russia, Flight Engineer Mikhail Kornienko of Russia, and NASA Flight Engineer Tracy Caldwell Dyson is scheduled for Friday, April 2, 2010 at 10:04 a.m. Kazakhstan time. Photo Credit (NASA/Bill Ingalls)

Security guards check the tracks ahead of the Soyuz. The Soyuz TMA-5 vehicle rolled to its launch pad at the Baikonur Cosmodrome in Kazakhstan, Tuesday, October 12, 2004, in preparation for its launch October 14 to send Expedition 10 Commander and NASA Science Officer Leroy Chiao, Flight Engineer and Soyuz Commander Salizhan Sharipov and Russian Space Forces cosmonaut Yuri Shargin to the International Space Station. Chiao and Sharipov will replace the Expedition 9 crew of Gennady Padalka and Mike Fincke, while Shargin will conduct eight days of scientific experiments. He will return to earth with the Expedition 9 crew October 24. Photo Credit: (NASA/Bill Ingalls)

Security controls access to the Soyuz capsule and test stand area, Friday, Oct. 5, 2004, at the Baikonur Cosmodrome. Expedition 10 Commander and NASA Science Officer Leroy Chiao, Flight Engineer and Soyuz Commander Salizhan Sharipov and Russian Space Forces Cosmonaut Yuri Shargin donned their launch and entry suits and climbed aboard their Soyuz TMA-5 for a dress rehearsal of launch day activities leading to their liftoff October 14 to the International Space Station. Chiao and Sharipov, the first crew of all-Asian extraction, will spend six months on the Station. Shargin will return to Earth October 24 with the Stations' current residents, Expedition 9 Commander Gennady Padalka and NASA Flight Engineer and Science Officer Mike Fincke. Photo Credit: (NASA/Bill Ingalls)