India’s premier rocket failed to put a navigation satellite into orbit during a launch this morning, after some unknown malfunction prevented the satellite from leaving the vehicle.

The rocket, known as the Polar Satellite Launch Vehicle, or PSLV, successfully took off from the Satish Dhawan Space Centre in southeastern India at 9:30AM ET. About a little over 10 minutes into the flight, however, the rocket seemed to be in a lower altitude than it need to be. A host during the live broadcast of the launch noted that there was a “variation” in the rocket’s performance. Later, an official with the Indian Space Research Organization (ISRO) confirmed that the payload fairing — the cone-like structure that surrounds the satellite on the top of the rocket — failed to separate and expose the satellite to space. So the satellite was effectively trapped inside the fairing and could not be deployed into orbit.

It’s an unexpected failure for a fairly reliable rocket

It seems possible that the rocket’s low trajectory had to do with the fact that the fairing didn’t separate, making the vehicle heavier than it was supposed to be. "If the fairing doesn’t separate you’re lugging along all this extra weight, so you lose velocity and height,” Jonathan McDowell, an astrophysicist at Harvard and spaceflight expert, tells The Verge. For now, it looks as if the top of the rocket with the trapped satellite will remain in orbit around Earth for the time being, says McDowell. Eventually, the air in Earth’s atmosphere will drag it down, though, and the vehicle will burn up during the descent.

It’s an unexpected failure for a fairly reliable rocket. Over the last 24 years, the PSLV has flown 41 times and has only suffered two failures in its launch history — the most recent mishap occurring during a mission in 1997. However, that mission was not a total loss as the satellite it carried was still able to make it to orbit. This was the first total failure of the rocket to happen since the PSLV’s very first failure in 1993.

The PSLV has become the backbone of India’s space program, used to launch probes to both Mars and the Moon. It’s also recently become a great ride-share option for satellite operators, allowing multiple probes to be sent into space during one launch. In February, the PSLV set a record by launching 104 satellites at once, which is the most that has ever gone up on a single rocket. Today’s launch was only supposed to send up one satellite, though — the eighth satellite of the Indian Regional Navigation Satellite System.

The PSLV also has some important launches coming. The vehicle is supposed to carry a private lander to the Moon for TeamIndus, a competitor in the Google Lunar X Prize to send a privately funded vehicle to the lunar surface. However, with today’s failure, it’s unclear how the rocket’s schedule will be affected in the months ahead.