SpaceX scrubbed its second attempt at launching a satellite on Thursday.
Just under two minutes away from the private space company's scheduled launch time, the countdown froze. A new launch day has not yet been set.
The mission, which SpaceX is carrying out on behalf of SES, could provide internet access to remote areas of the Asia-Pacific, including India, where about 1 billion people have no internet access.
The first launch attempt from the Cape Canaveral Air Force Station in Florida on Wednesday was aborted "out of an abundance of caution" because the SpaceX team was still working to "ensure liquid oxygen temperatures are as cold as possible," the company said. The colder the liquid oxygen, the more powerful the thrust.
The reason for aborting the second launch attempt on Thursday was not immediately clear.
But liquid oxygen -- which is a key rocket fuel ingredient -- was a key reason SpaceX could not reattempt the launch Thursday night.
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Nearly all of the fuel had been loaded from the holding tank and into SpaceX's Falcon 9 rocket when the launch was halted, so the rocket will need to be emptied.
Oxygen has to be kept at -297˚F in order to remain liquid, and Musk wants to use even colder oxygen because it offers a more powerful launch.
SpaceX didn't indicate what the target temperature is for this mission, but Musk said he wanted the liquid oxygen at -340˚F for a rocket that took off on a December mission.