Former Microsoft software developer Charles Simonyi flies during a parabolic flight aboard a zero-gravity simulator, a Russian IL-76 MDK aircraft used for astronauts' training flights in weightlessness, in Star City outside Moscow, on Feb. 26, 2007. As the world's fifth space tourist, Simonyi blasted off to the International Space Station on April 7, 2007. Maxim Marmur/AFP/Newscom/File
Russian cosmonaut Yuri Lonchakov (c.), US astronaut Michael Fincke (l.) and his compatriot, video game designer and space tourist Richard Garriott (r.) practice inside a Soyuz-TMA space flight simulator in Star City, Russia on Sept. 19, 2008. The crew visited the International Space Station on October 12, 2008. Dmitry Kostyukov/AFP/Newscom/File
A visitor tries a three-dimensional rolling hoop, one of the basic training items for astronauts and pilots at the Sichuan Science and Technology Museum in Chengdu, in China's southwestern Sichuan province on March 16, 2007. Liu Jin/AFP/Newscom/File
This undated fish-eye view of the interior of the Apollo Lunar Module Mission Simulator at the Kennedy Space Center shows a view of mission commander James McDivitt and lunar module pilot Russell Schweickart. NASA/CNP/Newscom/File
Expedition 14 flight engineer Sunita L. Williams is photographed just prior to her submersion in the water of the Neutral Buoyancy Laboratory near Johnson Space Center. SCUBA-equipped divers can be seen in the water, waiting to assist the crew members in their rehearsal intended to help prepare them for work on the exterior of the International Space Station. NASA/Marshall Space Flight Center/File
A projection of the earth rotates on a giant screen as the astronaut crew of Space Shuttle flight STS 115 train for their misson in a simulator at the Johnson Space Center in Houston on May 16, 2006. The training simulates the view through the windows overlooking the payload bay of the space shuttle orbiter. Astronaut Heidemarie Stefanyshyn-Piper is pictured at right, prior to her first space mission. Zuma/Newscom/File
Russian cosmonaut Alexander Kaleri (r.) and mission commander Sergei Zalyotin train underwater in Star City, Russia on Feb. 11, 2000. Training underwater is useful because it approximates weightless conditions, allowing astronauts to familiarize themselves with using tools and maneuvering in a Zero-G environment. Reuters/File
Canadian Guy Laliberte looks through the porthole of an altitude chamber as he prepares for exercises during a training session in the mock International Space Station (ISS) at the Star City space center outside Moscow, on Aug. 17. The Canadian billionaire owner of Cirque du Soleil is on the countdown to become the world's seventh, and Canada's first, space tourist slated to travel on a Russian Soyuz space craft to the ISS in September. Sergei Remezov/Reuters
This undated file image obtained on July 2, 2003 shows the Aquarius underwater habitat. NASA, the National Oceanic and Atmospheric Administration and the University of National Undersea Research Center at the University of North Carolina at Wilmington (UNCW), are conducting astronaut training on Aquarius, located off the coast of Key Largo, Florida. The NASA Extreme Environment Mission Operations program is designed to prepare astronauts for the physical and mental demands of working in space. AFP/NOAA/UNC Wilmington/Newscom/File
Guy Laliberte lies in a special capsule filled with gypsum to create a seat molding in Star City, Russia on July 8. Sergei Remezov/Reuters
Japan Aerospace Exploration Agency astronaut Koichi Wakata works and trains inside the Kibo laboratory airlock of the International Space Station prior to its delivery to orbit. NASA/File
The US government says that a Chinese fighter jet was responsible for a number of 'unsafe and unprofessional' intercepts of a US Navy surveillance and reconnaissance aircraft off the coast of China on Friday.
The Obama administration on Friday accused a Chinese fighter jet of conducting a "dangerous intercept" of a U.S. Navy surveillance and reconnaissance aircraft off the coast of China in international airspace — the fourth such incident since March.