STS-48

While that hasn't exactly been the case, there have been a few weird cases worth mentioning.

One moment that caused a big stir happened in 1991 during the Space Shuttle mission STS-48.

Technically speaking, the five astronauts who were aboard the shuttle didn't actually see this one, but it was caught by one of the backward-facing cameras mounted to the craft.

The zigzag video, as it is usually referred to by ufologists, shows a bunch of bright, glowing specks moving over the horizon of our planet.

Of course, say the UFO buffs out there, that first object has to be some kind of ship piloted by sentient beings in order to have the awareness to execute those kinds of evasive maneuvers.

As for the second one, it probably was some kind of projectile being fired at it.

The one thing that we can say for sure is that STS-48 was not the only occasion when the shuttle filmed objects moving on unexpected and unpredictable trajectories.

It happened again during STS-80 in 1996, when the camera caught multiple disk-like objects moving at various speeds over the Earth.