NASA said a rocket of unknown national origin that crashed into the moon earlier this year produced a double crater on the surface, an unexpected feat.

The agency’s Lunar Reconnaissance Orbiter, which collects data on the moon, spotted two craters after the “mystery rocket body” collided with the moon on March 4, NASA said recently.

It created an eastern crater about 19.5 yards in diameter and a western crater about 17.5 yards in diameter. 

The agency said the double crater might indicate that the rocket had a large mass on each end of it. A rocket that has used up its fuel usually will just have its mass on the end with the motor, with the other side being an empty fuel tank. 

The rocket’s origin is uncertain, but the double crater that it produced might reveal its identity, according to the release. 

A rocket body hitting the moon has not created a double crater before, the release states. 

NASA stated that the two large masses on each end of the rocket may have caused the craters, but noted that the impact marks are highly unusual. Spent rockets, according to NASA, tend to have a heavy motor at one end and a lighter empty fuel tank on the other, scientists say. The space agency did not offer any guesses on what the additional mass was. 

“Since the origin of the rocket body remains uncertain, the double nature of the crater may indicate its identity,” NASA said in a news release.

At least 47 NASA rocket bodies have created “spacecraft impacts” on the moon, according to 2016 data from Arizona State University. Four large moon craters attributed to Apollo 13, 14, 15 and 17 missions are substantially larger than each of the overlapping craters created by the March 4 impact, according to NASA. However, scientists said the maximum width of the new double crater is near that of the Apollo craters.

The Houston Chronicle reported Thursday that no space-exploring country has claimed the rocket as their own so far.