Skylab the first American space station was launched into orbit May 14, 1973, and problem plagued from day one.
Skylab 3,
the second crew to visit, consisted of Astronauts Alan Bean, Jack
Lousma, and Owen Garriott. Tasked with everything from
maintenance
to experiments both scientific and medical, they also faced a number of
crises during their short tenure (July 28, 1973, to September 25,
1973,) all of which were thankfully resolved and one occurrence of a
possible otherworldly nature which never 
was, an unidentified object
that followed the space lab purportedly undetected by NASA or NORAD, an
event which would become known in UFO circles as the "Skylab 3 UFO
Incident." A few days before returning to Earth and while out of radio contact, Garriott took photos of an anomalous object from Skylab’s wardroom window. The first recorded mention of the incident was between the astronauts and CAPCOM some four and a half hours later:
Lousma: Did you tell him about that satellite we saw?
Bean: Yes, we saw a great satellite. We didn’t know if we told you about it.
Lousma: The closest and brightest one we’ve seen.
Bean: Huge one [1]
Lousma: We’ve seen several. It was a red one
Capsule Communicator: No, you may have told someone but it wasn’t this team. I don’t remember hearing about it.
Lousma: I guess we didn’t report it. It was reflecting in red light and oscillating at, oh, counting its period of brightness to dimmest, about 10 seconds. It led us into sunset. [2] That was about three revs ago, I think. Something like that, wasn’t it Owen? (No answer).
A further allusion to the anomaly took place during a debriefing on October 4, 1973:
Garriott: Do you want to talk about that satellite?
Lousma: I saw a couple of satellites that appeared like a satellite would on Earth. I saw one that was not like one you would see on Earth, so why don’t you mention it.
Garriott: OK. About a week or 10 days before recovery and we were still waiting for information to be supplied to us about the identification. Jack first notices this rather large red star out the wardroom window.Upon close examination, it was much brighter than Jupiter or any of the other planets. It had a reddish hue to it, even though it was well above the horizon. The light from the Sun was not passing close to the Earth's limb at the time. We observed it for about 10 minutes prior to sunset. It was slowly rotating because it had a variation in brightness with a 10-seconds period. As I was saying, we observed it for about 10 minutes, until we went into darkness, and it also followed us into darkness about 5-seconds later. From the 5 to 10 second delay in its disappearance we surmised that it was not more than 30 to 50 nautical miles (35 to 58 statute miles or 56 to 93 km) from our location. From its original position in the wardroom window, it did not move more than 10 or 20 degrees over the 10 minutes or so that we watched it. Its orbit was very close to that of our own. We never saw it on any earlier or succeeding orbits and we'd be quite interested in having its identification established. It's all debriefed in terms of time on channel A, so the precise timing and location can be picked up from there.
Apparently the Channel A recorder was off, so determining the precise time and location of Skylab using that method was not possible. The information was later determined using NORAD tracking data.
So what was the large mysterious object purportedly undetected by NORAD (North American Aerospace Defense Command) that was observed in such close proximity to Skylab by its crew? Was it a piece of space junk, a terrestrial satellite, an extraterrestrial visitor, a flaw on the camera’s film or a smudge on the wardroom window? All have been offered as a possibilities, none with any great degree of certainty.
Skylab’s re-entry took place on July 11, 1979, its debris scattering across Western Australia. The Shire of Esperance, a government area covering 16,427 square miles, fined the American government $400.00 for littering. The fine has never been paid.
[1] Later calculations, admittedly based on a series of assumptions, indicated the object to be much larger than Skylab which at 78 tons was the largest man made construct in orbit at the time. (Mir launched in 1986 weighed 120 tons, the International Space Station will upon completion weigh in at nearly 500 tons.)
[2] Garriott later changed his story somewhat, saying the object did not lead the Skylab into sunset but rather followed it.