National Diving School director Jerome Vincent, wearing a Gandolfi space suit, trains in a swimming pool in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

Comex's astronaut-diver Julien Bonini, wearing a Gandolfi space suit, trains in a swimming pool in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

Comex Space division manager Peter Weiss (R) checks the Gandolfi space suit of National Diving School director Jerome Vincent (C) with Comex's astronaut-diver Julien Bonini (L) during a training session in a swimming pool in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

Comex Space division manager Peter Weiss (L) checks the Gandolfi space suit before a training session in Marseille October 21, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 21, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

National Diver School director Jerome Vincent, wearing a Gandolfi space suit, trains in a swimming pool in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY TPX IMAGES OF THE DAY) 

Comex Space division manager Peter Weiss leaves his office before a training session in Marseille October 21, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 21, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

The Gandolfi space suit of Comex is seen before a training session in a swimming pool in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

Comex Space division manager Peter Weiss (L) and engineer Thibaud Godert (R) move the Gandolfi space suit by a swimming pool before a training session in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

National Diving School director Jerome Vincent, wearing a Gandolfi space suit, trains in a swimming pool in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

Comex Space division manager Peter Weiss (R) looks at the Gandolfi space suit before a training session in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY TPX IMAGES OF THE DAY) 

Comex Space division manager Peter Weiss (L) checks the Gandolfi space suit of National Diving School director Jerome Vincent (R) during a training session in a swimming pool in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

National Diving School director Jerome Vincent, wearing a Gandolfi space suit, executes training procedures in a swimming pool in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

Comex Space division manager Peter Weiss (R) checks the Gandolfi space suit of National Diving School director Jerome Vincent (C) with Comex's astronaut-diver Julien Bonini (L) during training procedures in a swimming pool in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

Comex's astronaut-diver Julien Bonini ,wearing a Gandolfi space suit ,executes training procedures in a swimming pool in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

Comex Space division manager Peter Weiss (L) and Comex project engineer Virginie Taillebot (2ndL) move the Gandolfi space suit before a training session in Marseille October 21, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 21, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

National Diving School director Jerome Vincent wears a Gandolfi space suit as he executes training procedures in a swimming pool in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 22, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

Comex Space division manager Peter Weiss checks the Gandolfi space suit before a training session in Marseille October 21, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 21, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

Comex Space division manager Peter Weiss (L) and Comex project engineer Virginie Taillebot (R) move the Gandolfi space suit before a training session in Marseille October 21, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars. The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI 'Under the sea'. Picture taken on October 21, 2014. REUTERS/Jean-Paul Pelissier (FRANCE - Tags: SCIENCE TECHNOLOGY) 

Russian cosmonaut Alexander Misurkin, seen through the helmet of his spacesuit, takes part in a spacewalk training exercise at the cosmonaut training centre in Star City outside Moscow February 5, 2013. Misurkin, together with U.S. astronaut Christopher Cassidy and Russian cosmonaut Pavel Vinogradov, is preparing for a mission to the International Space Station in March 2013. REUTERS/Sergei Remezov (RUSSIA - Tags: SCIENCE TECHNOLOGY TRANSPORT) 

Russian cosmonauts Pavel Vinogradov (L) and Alexander Misurkin take part in a spacewalk training exercise at the cosmonaut training centre in Star City outside Moscow February 5, 2013. Vinogradov, Misurkin and U.S. astronaut Christopher Cassidy are preparing for a mission to the International Space Station in March 2013. REUTERS/Sergei Remezov (RUSSIA - Tags: SCIENCE TECHNOLOGY TRANSPORT) 

Russian cosmonauts Pavel Vinogradov (L) and Alexander Misurkin take part in a spacewalk training exercise at the cosmonaut training centre in Star City outside Moscow February 5, 2013. Vinogradov, Misurkin and U.S. astronaut Christopher Cassidy, are preparing for a mission to the International Space Station in March 2013. REUTERS/Sergei Remezov (RUSSIA - Tags: SCIENCE TECHNOLOGY TRANSPORT) 

Moisture trails off the wings on the Space Shuttle Atlantis as she comes in to land at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Pierre DuCharme (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Space Shuttle Atlantis is slowed by a drag chute after landing to end Mission STS-132 at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Chris O'Meara/Pool (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Space Shuttle Atlantis rolls past rescue personnel during landing on runway 33 to end Mission STS-132 at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Joe Skipper (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Technicians look for systems leaks on the space shuttle Atlantis after landing to end Mission STS-132 at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Red Huber/POOL (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Technicians look for systems leaks on the Space Shuttle Atlantis after landing, to end Mission STS-132, at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex.REUTERS/Red Huber-POOL (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Space Shuttle Atlantis prepares to land, ending Mission STS-132, at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Pierre DuCharme/Pool (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Space Shuttle Atlantis releases its drag chute after landing to end Mission STS-132 at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Chris O'Meara/Pool (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Space Shuttle Atlantis touches down to end Mission STS-132 at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Chris O'Meara/Pool (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Space Shuttle Atlantis releases its drag chute after landing to end Mission STS-132 at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Joe Skipper (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Space Shuttle Atlantis deploys its drag chute after landing to end Mission STS-132 at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Joe Skipper (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Space Shuttle Atlantis rolls past with its drag chute deployed to end Mission STS-132 at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Chris O'Meara/Pool (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Space Shuttle Atlantis approaches the runway to land at the end of Mission STS-132 at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Pierre DuCharme/Pool (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Space Shuttle Atlantis lands to end Mission STS-132 at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010. Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Pierre DuCharme (UNITED STATES - Tags: SCI TECH TRANSPORT) 

Space Shuttle Atlantis approaches the runway to end Mission STS-132 at the Kennedy Space Center in Cape Canaveral, Florida May 26, 2010.Atlantis and its crew of six astronauts carried a new Russian-built module to the International Space Station and conducted three spacewalks to install new batteries and spare components on the outside of the orbital laboratory complex. REUTERS/Pierre DuCharme/POOL (UNITED STATES - Tags: SCI TECH TRANSPORT IMAGES OF THE DAY) 

Japan Aerospace Exploration Agency astronaut Soichi Noguchi answers a question during a news conference at the Johnson Space Center in Houston September 17, 2009. Nouguchi will serve as flight engineer on the International Space Station and previously flew on STS-114 and is a veteran of three spacewalks. REUTERS/Donna Carson (UNITED STATES SCI TECH POLITICS) 

Japan Aerospace Exploration Agency astronaut Soichi Noguchi answers a question during a news conference at the Johnson Space Center in Houston September 17, 2009. Nouguchi will serve as flight engineer on the International Space Station and previously flew on STS-114 and is a veteran of three spacewalks. REUTERS/Donna Carson (UNITED STATES SCI TECH POLITICS) 

STS-126 Commander Christopher Ferguson (L) answers a question during a news conference with Endeavour crewmembers (L-R) Pilot Eric Boe (partially obscured), mission specialists Donald Pettit, Stephen Bowen and Heidemarie Stefanyshyn-Piper at the Johnson Space Center in Houston November 3, 2008. Dubbed the "Extreme Home Improvement" mission, Endeavour, scheduled for launch November 13th will deliver seven tons of supplies and equipment and will perform four spacewalks to repair the International Space Station's solar arrays. REUTERS/Donna Carson (UNITED STATES) 

STS-126 mission specialist Sandra Magnus (R) talks during a news conference with fellow Endeavour crewmembers (L-R) Commander Christopher Ferguson, Pilot Eric Boe, Donald Pettit, Stephen Bowen, Heidemarie Stefanyshyn-Piper and Robert Kimbrough at the Johnson Space Center in Houston November 3, 2008. Dubbed the "Extreme Home Improvement" mission, Endeavour, scheduled for launch November 13th will deliver seven tons of supplies and equipment and will perform four spacewalks to repair the International Space Station's solar arrays. REUTERS/Donna Carson (UNITED STATES) 

STS-126 Commander Christopher Ferguson (L) listens to a question at a news conference with Endeavour crewmembers (L-R) Pilot Eric Boe, mission specialists Donald Pettit, Stephen Bowen, Heidemarie Stefanyshyn-Piper, Robert Kimbrough and Sandra Magnus at the Johnson Space Center in Houston November 3, 2008. Dubbed the "Extreme Home Improvement" mission, Endeavour, scheduled for launch November 13th will deliver seven tons of supplies and equipment and will perform four spacewalks to repair the International Space Station's solar arrays. REUTERS/Donna Carson (UNITED STATES) 

Skydiving instructor Chris Gray from the U.S. freefalls during a skydiving session in the Spacewalk vertical wind tunnel in Abu Dhabi October 11, 2008. Spacewalk, measuring at 3.5 meters wide and 7 meters high, is the first indoor skydiving facility in the Middle East, with winds up to 150km per hour propelling the divers off the floor. REUTERS/Jumana El Heloueh (UNITED ARAB EMIRATES) 

Skydiver Bonnie Gray from the U.S. freefalls in the Spacewalk vertical wind tunnel in Abu Dhabi October 11, 2008. Spacewalk, measuring at 3.5 meters wide and 7 meters high, is the first indoor skydiving facility in the Middle East, with winds up to 150km per hour propelling the divers off the floor. REUTERS/Jumana El Heloueh (UNITED ARAB EMIRATES) 

Skydiver Bonnie Gray from the U.S. freefalls in the Spacewalk vertical wind tunnel in Abu Dhabi October 11, 2008. Spacewalk, measuring at 3.5 meters wide and 7 meters high, is the first indoor skydiving facility in the Middle East, with winds up to 150km per hour propelling the divers off the floor. REUTERS/Jumana El Heloueh (UNITED ARAB EMIRATES) 

Skydivers Bonnie (L) and Chris Gray from the U.S. freefall during their skydiving session in the Spacewalk vertical wind tunnel in Abu Dhabi October 11, 2008. Spacewalk, measuring at 3.5 meters wide and 7 meters high, is the first indoor skydiving facility in the Middle East, with winds up to 150km per hour propelling the divers off the floor. REUTERS/Jumana El Heloueh (UNITED ARAB EMIRATES) 

Skydiving instructor Chris Gray looks on as his wife Bonnie carries their two-year-old daughter Skylar in the Spacewalk vertical wind tunnel in Abu Dhabi October 11, 2008. Spacewalk, measuring at 3.5 meters wide and 7 meters high, is the first indoor skydiving facility in the Middle East, with winds up to 150km per hour propelling the divers off the floor. REUTERS/Jumana El Heloueh (UNITED ARAB EMIRATES) 

Skydiving instructor Chris Gray adjusts the goggles on his two-year-old daughter Skylar ahead of their skydiving session in the Spacewalk vertical wind tunnel in Abu Dhabi October 11, 2008. Spacewalk, measuring at 3.5 meters wide and 7 meters high, is the first indoor skydiving facility in the Middle East, with winds up to 150km per hour propelling the divers off the floor. REUTERS/Jumana El Heloueh (UNITED ARAB EMIRATES) 

Skydiving instructor Chris Gray adjusts the goggles on his two-year-old daughter Skylar ahead of their skydiving session in the Spacewalk vertical wind tunnel in Abu Dhabi October 11, 2008. Spacewalk, measuring at 3.5 meters wide and 7 meters high, is the first indoor skydiving facility in the Middle East, with winds up to 150km per hour propelling the divers off the floor. REUTERS/Jumana El Heloueh (UNITED ARAB EMIRATES) 

Two-year-old Skylar Gray stands next to the Spacewalk vertical wind tunnel ahead of her skydiving session in Abu Dhabi October 11, 2008. Spacewalk, measuring at 3.5 meters wide and 7 meters high, is the first indoor skydiving facility in the Middle East, with winds up to 150km per hour propelling the divers off the floor. REUTERS/Jumana El Heloueh (UNITED ARAB EMIRATES) 

Bonnie Gray from the U.S. touches the window as her two-year-old daughter Skylar (L) and her husband Chris freefall in the Spacewalk vertical wind tunnel in Abu Dhabi October 11, 2008. Spacewalk, measuring at 3.5 meters wide and 7 meters high, is the first indoor skydiving facility in the Middle East, with winds up to 150km per hour propelling the divers off the floor. REUTERS/Jumana El Heloueh (UNITED ARAB EMIRATES) 

Skydiver Chris Gray freefalls with his two-year-old daughter Skylar in the Spacewalk vertical wind tunnel in Abu Dhabi October 11, 2008. Spacewalk, measuring at 3.5 meters wide and 7 meters high, is the first indoor skydiving facility in the Middle East, with winds up to 150km per hour propelling the divers off the floor. REUTERS/Jumana El Heloueh (UNITED ARAB EMIRATES) 

An exterior view of the vertical wind chamber Spacewalk in Abu Dhabi October 11, 2008. Spacewalk, measuring at 3.5 meters wide and 7 meters high, is the first indoor skydiving facility in the Middle East, with winds up to 150km per hour propelling the divers off the floor. REUTERS/Jumana El Heloueh (UNITED ARAB EMIRATES)