Alrights lets re-examine something here from what the men themselves stated:
It was slowly rotating because it had a variation in brightnesswith 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 it's 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.”
Alright I bolded (is that the right word? anyway) the key phrases. So it was slowly rotating and had a variation in brightness. As soon as I heard
this I immediatley thought of a solar flare. Then again he stated that they went further into darkness and the object came back 5 seconds later. He
also stated that it did not move than 10 or 20 degrees, which would be about correct. Because they were moving as well. There moving would give the
false impression that the object was also moving. But why did it disappear? Well for one thing, its outter space, there are dust clouds in outer space
and very thick dust clouds. There could have been a blind spot on the craft (like a blind spot on a car) and many other fcators. Its orbit was very
close to our own, I bet it felt close, but was it really close? I doubt it, much like the brighter a light seems the closer it logically is, but with
a simple experiment:
You have light A and light B. Light A is 30 feet away from you with a generic light bulb that gives off 80 watts of light. But light B is 50 feet away
and has a designers light bulb that gives off 500 watts of light. Now logically the brightest one is closer (Light A), but that is not the case here,
infact the furthest one is the brightest (Light B). You would say light B is closer because it is brighter, you would be wrong.
Its a simple light trick, luckily my chemistry teacher back in the day shpowed me this experiment and I have never forgotten it. So I am not calling
these men liars, I just believe that they came up with the wrong conclusion.
Now looking at these pictures of solar flares, it really looks like the image you presented. Tak ethe first one, to me it looks like some sort of
bird, a phoenix. The second one is just a solar flare from our own sun. But solar flares can happen on any star, so chances are they were right. It
was a massive, bright object because its a solar flare. Thats what I think, I am probably wrong but it makes sense.