“If I heard these sounds driving my car, I’d pull over and call for a tow,” said Dave Gruel, lead engineer for Mars 2020’s EDL Camera and Microphone subsystem. “But if you take a minute to consider what you’re hearing and where it was recorded, it makes perfect sense.”

Perseverance recorded the sounds during a 90-foot (27.3-meter) drive March 7, according to NASA. The rover’s top speed is a little less than 0.1 mph, or about 152 meters per hour.

The longer, raw audio clip includes a high-pitched scratching noise. The origin of the sound remains a mystery.

“Perseverance’s engineering team continues to evaluate the source of the scratching noise, which may either be electromagnetic interference from one of the rover’s electronics boxes or interactions between the mobility system and the Martian surface,” NASA said in a statement. “The EDL microphone was not intended for surface operations and had limited testing in this configuration before launch.”

Sounds travel much differently on Mars than on Earth. The Martian atmosphere is less than 1 percent the thickness of Earth’s atmosphere at sea level, and is primarily made up of carbon dioxide, not nitrogen and oxygen.”

Darn, I expected to hear “Greetings, Earthling”