An unmanned SpaceX Falcon 9 rocket explodes after liftoff from Cape Canaveral, Florida, June 28, 2015. The rocket exploded about two minutes after liftoff on Sunday, destroying a cargo ship bound for the International Space Station, NASA said. REUTERS/Mike Brown TPX IMAGES OF THE DAY 

An unmanned SpaceX Falcon 9 rocket launches from Cape Canaveral, Florida, June 28, 2015. The rocket exploded about two minutes after liftoff on Sunday, destroying a cargo ship bound for the International Space Station, NASA said. REUTERS/Mike Brown 

An unmanned Space Exploration Technologies Falcon 9 rocket launches in Cape Canaveral, Florida, June 28, 2015. The rocket exploded about two minutes after liftoff from Cape Canaveral Air Force Station on Sunday, destroying a cargo ship bound for the International Space Station, NASA said. REUTERS/Michael Berrigan 

An unmanned Space Exploration Technologies Falcon 9 rocket launches in Cape Canaveral, Florida, June 28, 2015. The rocket exploded about two minutes after liftoff from Cape Canaveral Air Force Station on Sunday, destroying a cargo ship bound for the International Space Station, NASA said. REUTERS/Michael Berrigan 

An unmanned Space Exploration Technologies Falcon 9 rocket launches in Cape Canaveral, Florida, June 28, 2015. The rocket exploded about two minutes after liftoff from Cape Canaveral Air Force Station on Sunday, destroying a cargo ship bound for the International Space Station, NASA said. REUTERS/Michael Berrigan 

An unmanned Space Exploration Technologies Falcon 9 rocket launches in Cape Canaveral, Florida, June 28, 2015. The rocket exploded about two minutes after liftoff from Cape Canaveral Air Force Station on Sunday, destroying a cargo ship bound for the International Space Station, NASA said. REUTERS/Michael Berrigan 

An unmanned SpaceX Falcon 9 rocket explodes after lift-off from Cape Canaveral, Florida, June 28, 2015. The rocket exploded about two minutes after liftoff on Sunday, destroying a cargo ship bound for the International Space Station, NASA said. REUTERS/Mike Brown 

Mike Suffredini, NASA manager of the International Space Station Program speaks at a media event after an unmanned Space Exploration Technologies (SpaceX) Falcon 9 rocket broke apart after liftoff in Cape Canaveral, Florida, June 28, 2015. The rocket exploded about two minutes after liftoff from Cape Canaveral Air Force Station on Sunday, destroying a cargo ship bound for the International Space Station, NASA said. REUTERS/Mike Brown