On September 12th, 1991, a space shuttle rocketed off Earth from Kennedy Space Center in Florida on a mission to release a research satellite. The mission, designated STS-48, was a success, and the five astronauts who crewed the craft safely landed back on Earth six days later at a U.S. Air Force base in California.

Most people probably either don’t remember the mission or have never even heard of it. However, those who do remember STS-48 might remember it for the unique coverage it received after the mission’s completion—coverage that addressed something altogether different from a satellite launch. A video sequence recorded by the space shuttle Discovery during that six-day period shows something odd—something that many believe was of extraterrestrial origin.

In the black and white footage caught on September 15th, a camera is trained towards the earth. At some point during the video, an object that appears white and large appears in the center of the screen just below the earth’s horizon. The object moves from right to left at a moderate rate of speed at what appears to be a course paralleling the earth’s atmosphere. Approximately 15 seconds after it appears, a broader flash is seen on the screen, but it’s unclear what was the source of the flash. At that moment, the object makes a sudden turn greater than 90 degrees and moves off at an extremely accelerated pace toward the top of the screen and away from Earth.

The object described above wasn’t the only object that was visible on the screen and that appeared to change course when the flash occurred. A close and repeated examination of the video—which can be found on YouTube—shows other objects changing direction following the flash event.

Many claim the video shows that the space shuttle was being followed by extraterrestrial spacecraft. Others just claim the video captured evidence of the existence of otherworldly spacecraft. Of note, the footage gained much attention and was aired by media outlets such as CNN’s Larry King Live.

Explanations provided by different “experts” state that the objects were shuttle debris, such as ice, that were propelled away from the Discovery when certain engineered thrusters activated, also explaining the sudden flash of light. The objects have also been described as being meteors, satellites, and other space debris. Although many have attempted to debunk the UFO theory, doubt still abounds. For one reason, many “experts” in favor of a UFO theory have explained away the more rational theories mentioned already.

So, UFO, or not? Truly, something seems odd about the footage, but it’s hard to definitively say. Probably the one verity here is that those in the UFO camp will continue to believe the video shows proof of extraterrestrial spacecraft, while those who look for other explanations will believe or continue to look for other rationalizations other than UFO.