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I live just south of Sydney Australia, and I went outside to watch the ISS pass overhead on Friday night. The ISS was following a smaller object easily visible to the naked eye.

Sydney time 20.43 or UTC 9.43. (Friday March 8) The smaller object was ahead of the ISS by maybe 25 degrees. Appeared to be moving at exactly the same speed and trajectory.

Was this the the SpaceX Crew Dragon capsule? Sorry if this is the wrong place to ask.

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    $\begingroup$ It was definitely the ISS, i went outside specifically to watch it fly over thanks to the nasa website. Sydney time 20.43 or UTC 9.43. (Friday March 8) The smaller object was ahead of the ISS by maybe 25 degrees. Appeared to be moving at exactly the same speed and trajectory. I’m really just interested to know if the other object could have been the capsule. $\endgroup$
    – Dave
    Commented Mar 11, 2019 at 11:43
  • $\begingroup$ Okay thanks, I've added the info to your question. In Stack Exchange comments are considered temporary, and many readers don't read through the comments for important information. fyi I've just asked Difference between "undock" and "depart" (SpaceX Dragon Mission 1); when did it leave? in Space SE. $\endgroup$
    – uhoh
    Commented Mar 11, 2019 at 11:57
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    $\begingroup$ Thank you, I’ll edit the original question next time. $\endgroup$
    – Dave
    Commented Mar 11, 2019 at 12:13

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I have certainly watched the ISS and an undocked Shuttle Orbiter chase each other across the sky. Since they appeared to be of equal brightness, I didn't know which was which. Their angular separation from my POV was approximately 20°, so their actual separation would have been about 150km. It was one of the last Shuttle flights, so I was very lucky to see it.

It is possible that you saw the Dragon capsule, and it would certainly have appeared to be be fainter than the ISS. The easiest way to establish the fact is by using a program like Stellarium. This will show you if the ISS was visible at your location, given the date and time of day.

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The SpaceX YouTube video SpaceX Crew Dragon Returns from Space Station shows the undocking and parts of the reentry and landing.

Orbits work a little counterintuitively when it comes to velocity. To drop to a lower orbit the capsule will point it's engines forward so that they receive an impulse backward, but since they loose altitude this way the speed of the capsule actually increases. As they loose altitude then they will continue to move forward of the ISS, until they start losing substantial amounts of velocity due to drag and begin ballistic reentry.

So yes you will see the capsule ahead of the ISS as it begins to loose altitude.

FYI you'll hear mention of the Keep-Out ellipse in the video, you can read more about that in answers to What is the “ISS's Keep Out Sphere” and what is its radius?

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