NASA says that a mysterious rocket that crashed into the moon earlier this year unexpectedly created a double crater on the moon’s surface.

NASA said its Lunar Reconnaissance Orbiter found two craters on the moon after the “mystery rocket body” crashed on March 4.

One crater is roughly 19.5 yards in diameter, while the other is about 17.5 yards.

“The double crater was unexpected and may indicate that the rocket body had large masses at each end,” the agency said.

“Typically a spent rocket has mass concentrated at the motor end; the rest of the rocket stage mainly consists of an empty fuel tank.”

NASA noted that “the origin of the rocket body remains uncertain,” but “the double nature of the crater may indicate its identity.”