Authorities on Wednesday started investigating what made an unmanned U.S. supply rocket explode in a fireball moments after lifting off from a launchpad in Virginia, destroying supplies and equipment bound for the International Space Station.

The 14-story Antares rocket, built and launched by Orbital Sciences Corp., blasted off from the Wallops Flight Facility at 6:22 p.m. on Tuesday but burst into flames moments later, the first disaster since NASA turned to private operators to run cargo to the space station.

Orbital Sciences stock fell 15.9 percent to $25.54 on Wednesday.