"But be patient with us. Let's make sure that the vehicle is ready to go and that our team is really certain before we hit the button."

As the ISS passed above the city-state of Singapore at 3:18 a.m. local time on June 15, the crew witnessed an electrifying storm with flashes of lightning across the landscape. The flash, which appears almost spherical in the image, is due to lightning striking the clouds above the urban area, according to NASA.

An international crew is readying for Thursday's planned launch of a NASA mission to the International Space Station after arriving at the Kennedy Space Center.