Curiosity, a huge accomplishment in interstellar exploration, is the largest and most capable rover ever delivered to the surface of a planet. After launching from Earth on November 26, 2011, and entering the Martian atmosphere at a breakneck speed of 13,000 miles per hour, the rover broke ground on Mars at the Gale Crater on August 5, 2012. Curiosity was sent to the Red Planet to answer the question: Did Mars ever have the right environmental conditions to support small life forms called microbes?

When the one-Earth-year anniversary of this rover's monumental landing rolled around, it was especially sentimental. On this day, the lonely rover performed a special task: it sang "Happy Birthday" to itself all alone. Adorable, scientifically impressive, or just... a little sad?

Researchers at NASA Goddard Space Flight Center programmed the celebratory song to play on August 5, 2013. To do this, Curiosity produced a series of frequencies that mimicked the notes in the song. As reported by The Washington Post, NASA technologist Florence Tan explained that "the rover's sample analysis unit vibrates at different frequencies to move soil samples" in order to create frequencies that sound like the song. It feels a little solemn knowing that the rover will never make it the 208-million-mile trek back home to celebrate on Earth.

Correction 8/9/2018: An old version of this article stated that the Curiosity Rover sings a birthday song to itself every year. But as stated by the Curiosity Rover Twitter account, "The reports of my singing are greatly exaggerated. I only hummed "Happy Birthday" to myself once, back in 2013." Why did it stop? "The answer to your question will sound rather cold and unfeeling," Florence Tan, the deputy chief technologist at NASA's Science Mission Directorate, told The Atlantic. "In a nutshell, there is no scientific gain from the rover playing music or singing 'Happy Birthday' on Mars." Happy birthday anyway, little guy.