In this handout image provided by NASA, the space shuttle Endeavour is seen on launch pad 39a as a storm passes by prior to the rollback of the Rotating Service Structure (RSS) April 28, 2011, at Kennedy Space Center in Cape Canaveral, Florida. During the 14-day mission, Endeavour and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts, including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for April 29 at 3:47 p.m. EDT.

An employee of the British Museum examines a silver coin dating from 900 AD which is part of the Silverdale Viking Hoard on December 14, 2011 in London, England. The hoard, which was discovered by local metal-detectorist Darren Webster in North Lancashire, comprises of 201 silver objects including arm-rings, coins, finger-rings, ingots, brooch fragments and fine wire braid. (Photo by Oli Scarff/Getty Images)

Demonstrators take part in a mass anti-Putin rally on December, 24, 2011 in Moscow, Russia. Tens of thousands of demonstrators rallied in cities across Russia to protest alleged vote fraud in recent parliamentary elections and to express their discontent with Prime Minister Vladimir Putin, leader of the dominant United Russia party. (Photo by Alexander Aleshkin/Epsilon/Getty Images)

Photo by: Rustem Adagamov; Source: LiveJournal

A reveller dressed as Spider-Man takes part in a presentation at the top of a building during an annual block party known as “Enquanto isso na Sala da Justiça” (Meanwhile, in the justice room), one of the many carnival parties taking place in the neighbourhood of Olinda, Brazil February 7, 2016. (Photo by Ueslei Marcelino/Reuters)

Pokot men carry a part of a carcass of a bull killed by a young man during an initiation ceremony in Baringo County, Kenya, January 20, 2016. Far from the bustling city of Nairobi, in an isolated corner of Kenya's Rift Valley, young men from the Pokot community spear a bull in a ceremony called Sapana that takes them into adulthood. (Photo by Siegfried Modola/Reuters)

Pilgrims wearing traditional dresses take part during the Queen of Angeles pilgrimage in Alajar, southern Spain, September 8, 2015. Every year, devotees converge at the Arias Montano crag to pay homage to the Queen of Angeles during an annual pilgrimage which combines religious fervour and festive colour. (Photo by Marcelo del Pozo/Reuters)

A model wears a creation by Taiwanese fashion house Shiatzy Chen as part of its Spring-Summer 2016 ready-to-wear fashion collection, presented during the Paris Fashion Week in Paris, France, Tuesday, October 6, 2015. (Photo by Jerome Delay/AP Photo)

A fireball erupts from a 16-inch gun on the battleship USS Wisconsin during a live fire exercise in the Persian Gulf, October 13, 1990. The ship is in the Gulf as part of Operation Desert Shield. (Photo by John Gaps III/AP Photo)