On Sunday at 3:40pm EDT, Commander Chris Hadfield will hand command of the Space Station over to Russian Cosmonaut Pavel Vinogradov.

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Three crew members, Cassidy and Russian cosmonauts Alexander Misurkin and Pavel Vinogradov, will remain on the space station when the others leave.

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Cassidy and Russian cosmonauts Alexander Misurkin and Pavel Vinogradov will stay behind.

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This pioneering, fast-track crew was made up Pavel Vinogradov and Aleksandr Misurkin from Russia's space agency, as well as NASA astronaut Chris Cassidy.

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The arrival of Russians Pavel Vinogradov and Alexander Misurkin and Chris Cassidy of the US brings the number of crew at the ISS to six.

BBC: Soyuz spacecraft docks at ISS after just six hours

The three new arrivals were greeted by NASA's Chris Cassidy and Russians Alexander Misurkin and the station's commander Pavel Vinogradov, who have been aboard the space station since late March.

NPR: Soyuz Capsule Docks With Space Station