Watch: SpaceX spy satellite launch leaves otherworldly spiral in the sky

CAPE CANAVERAL, Fla. - Monday’s SpaceX launch was carrying a classified satellite to space, but the secret payload was not the cause of an unusual glowing spiral seen in the skies of Europe.

Social media was filled with photos and videos of the blue swirling cloud left behind by the rocket – an unusual, though not unprecedented, sight.

NROL-69 launch

What we know:

A SpaceX Falcon 9 rocket lifted off from Cape Canaveral just before 2 p.m. on Monday, carrying a satellite for the U.S. National Reconnaissance Office. While the rocket’s first stage returned for landing in Florida, the upper stage and satellite continued northeast over Europe as they pushed into orbit. 

The intelligence agency confirmed that the satellite safely reached orbit. "It hit the mark, right in the middle," Col. Jim Horne said in a NRO press release.

What we don't know:

Details about the NROL-69 mission are classified, so it’s not clear what the satellite was or what its purpose in space will be. The NRO referred to the satellite only as a "national security payload."

Such secret missions are not uncommon; in the last two years alone, the NRO says it has launched more than 150 satellites.

Glowing spiral in the sky

Not long after the launch, a swirling blue cloud, almost like a galaxy, appeared in the skies from England to France to Croatia.

The backstory:

The cause of the cloud was either an exhaust plume or leftover fuel being vented from the upper stage of the rocket. 

SpaceX and other launch companies routinely try to minimize space junk by allowing spent upper stages to burn up in the atmosphere. It’s likely that, after the upper stage released the satellite, engineers commanded it to dump fuel before it burned up. It may have been slowly rotating or spinning in space, creating the slow swirling effect.

That plume, then, caught the sunlight, making it stand out in the dark night sky.

What they're saying:

While most observers enjoyed the spectacle, a few seemed skeptical of the explanation, while others joked it was a wormhole from Star Trek.

"Looked incredible," one user from North Lincolnshire posted on X.

"BS," another responded. "We've all seen Men In Black."

Dig deeper:

While the swirling sight was unusual, it was not unprecedented. The phenomenon happened several times over the last few years in Europe, but also Hawaii and the Arctic following launches from Florida, California, and Alaska respectively.

The swirling spiral is similar to the so-called ‘space jellyfish’ that can be seen when a rocket is launched just before sunrise or after sunset. The rocket’s exhaust plume is illuminated by the sun, creating a cloud that appears to be shimmering and pulsing to observers on the ground in darkness.