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Starlink satellites move in the same altitude region as the ISS (on their way up and eventually back down) and are particularly noticeable for weeks after deployment as "trains".

Have one of these trains been spotted by astronauts on the ISS?

Considering the potential vantage point in Earth's shadow looking towards the direction where the Sun has just set or will soon rise, it's seems like this is inevitable.

uhoh
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  • One factor that would complicate seeing this from the ISS is that a large part of why the satellites are so visible is that just before dawn (or after dusk), an object overhead can reflect the sun since the sun hasn't set on it yet. This is optimal viewing conditions since everything except the satellite is dark. This won't happen from a space based observer nearly as much. – Oscar Smith May 07 '20 at 03:21
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    OscarSmith I think the geometry can work; the ISS could be in Earth's shadow and easily see LEO objects if they were bright enough, and they have several flat reflective surfaces that these days are oriented during raising to avoid reflecting towards Earth so no need to view them overhead for them to be bright necessarily. I have a hunch that SpaceX could even choreograph a light show for ISS specifically using synchronized attitude controls if they wanted to. – uhoh May 07 '20 at 03:50
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    Out of curiosity: have you tried to google "starlink iss" (a.k.a "show any research effort") just to see pictures of starlink satellites taken from ISS-astronauts ;-) ? – CallMeTom May 07 '20 at 04:23
  • @CallMeTom for a small fraction of my questions I may already know an answer but suspect there may be a better one out there writable by someone more familliar with the topic. The goal is to facilitate good answers. In general my questions are well researched but in this case it's just not necessary. A good answer may also be the source of interesting follow-up questions. – uhoh May 07 '20 at 05:05
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    I wrote a quick answer, but indeed a simple Google search would have provided OP with an answer ;) – yzokras May 07 '20 at 07:22
  • @yzokras but now you have provided an answer for all readers, not just me. – uhoh May 07 '20 at 07:33
  • @CallMeTom I've added another anwer – uhoh May 07 '20 at 15:08
  • -1 if you know the answer, post it at the same time. that's what the answer this question tick box is for –  May 08 '20 at 09:48
  • @JCRM 1) I could imagine an answer but of course that didn't mean that it would turn out to be the* answer, and it turned out it wasn't! I won't tell you which of these two very different answers I was thinking along the lines of, and which one surprised me afterward! 2) What tick box? – uhoh May 08 '20 at 09:56
  • The one at the bottom, labelled " Answer your own question – share your knowledge, Q&A-style " –  May 08 '20 at 12:36
  • @JCRM oh this which links to t’s OK to Ask and Answer Your Own Questions; I'd never really paid attention to that. It seems to disappear once the question is first posted. But I'm happier that a relatively new user picked up a little reputation. I don't see any rules that state one must answer one's own question if one thinks one might know the answer. I think my way is also just fine. – uhoh May 08 '20 at 12:48
  • think "if you might know the answer" suggests one might have done a little more research before asking the question –  May 08 '20 at 17:31
  • @JCRM have a nice day! :-) – uhoh May 08 '20 at 17:48
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    I have a vid recorded from the ISS Live stream HD camera on a dawn that is most likely one of the starlink trains passing by. I tracked both and their position was exactly what I saw. About 30 km away (highest ISS 30 km). My only question would be whether it could be the starlink by the distance. – Apaiss May 22 '20 at 04:35
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    @Apaiss if you can post all the relevant information which is mostly the time that the video represents and a screen shot, that can be checked based on the TLEs of the ISS and satellites. But if you don't know the time that the ISS Live stream was being generated, then it probably can't be checked. – uhoh May 22 '20 at 04:54
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    Cool, I have this data. I will do it soon. I recorded a video with the tracker showing both (ISS and possibly the train) on the satflare, with day and time data, from the moment of the sighting. Thank you! – Apaiss May 22 '20 at 05:17
  • @uhoh, I have a strong suspicion that it was the starlinks, do I put my material here or open a new question about it by asking the opinion of colleagues? I not sure about what to do. – Apaiss May 26 '20 at 21:28
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    @Apaiss In this case maybe ask a new question first. In that case you can explain what you've got, what you think it is and ask if the identification is likely to be correct or not. Based on further input you can consider posting a supplemental answer here. Since the question asks if astronauts have seen them, a recording by an automated camera doesn't exactly count though, so I think starting with a new question is the best first step. – uhoh May 27 '20 at 00:35
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    @uhoh Thank you! – Apaiss May 27 '20 at 01:06

2 Answers2

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Yes, it happened at least on 13th April 2020 at 21:25:02 UTC:

The image above (image ISS062-E-148365, original at high resolution here) was shot from the International Space Station (ISS) on 13 April 2020, 21:25:02 UT. It shows the Aurora Australis (southern lights) and a train of SpaceX Starlink satellites.

The presence of the Starlink train in this image was first noted by Twitter user Riccardo Rossi (@RikyUnreal) and brought to my attention by Huub Eggen (@phi48). It is present in two earlier images as well, taken the preceeding minute (images ISS062-E-148363 and ISS062-E-148364).

ISS was at 48.25 S, 81.03 E and 440 km altitude at the time the photo above was taken. With this information, I came to the following probable satellite ID's (annotations in image below) for the objects in the imaged "train": these are all objects from the 17 February 2020 launch ("Starlink 4").

enter image description here

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yzokras
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  • +1 Thanks! I like the 2nd image in the blog post showing the tentative identifications. We can probably call these Starlinks because "if not, what else?" but it's better to see that their apparent position and time corresponds with known TLE data. – uhoh May 07 '20 at 07:32
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    This is by far the most epic photograph of a Starlink train. – Everyday Astronaut May 07 '20 at 13:38
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Have astronauts seen Starlink trains?

Technically, No.

Of course @X's affirmative answer is basically right, but viewed from Space at 17500 MPH things move differently.

Since the ISS is moving just as fast as they are and in a different direction, the apparent motion of the satellites is oblique to the orbit they travel on.

Seen this way it's not a "train" with each satellite as a car moving (roughly) along the same track, but instead looks more like echelon formation flying.

See also here

Cropped and rotated NASA photo ID: ISS062-E-148365 from here

Cropped and rotated NASA photo ID: ISS062-E-148365

Example: USAF Fighter School Acrojets demonstration team - 1950, flying in echelon formation Source

USAF Fighter School Acrojets demonstration team - 1950, flying in echelon formation

uhoh
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  • I had to re-read the answer. I think this answer might give people [who are reading in haste] the wrong idea that you're dismissing that orbital photograph as a formation-flying squadron of jets. Could you reword it? (P.S. I'm not the downvoter :) – William R. Ebenezer May 07 '20 at 16:49
  • @WilliamR.Ebenezer I don't know how to write for people who are reading in haste any better than this; the first sentence says the other answer is basically right, the second sentence "the apparent motion of the satellites is oblique to the orbit they travel on" calls the satellites satellites. I will make the image illustrating the echelon formation smaller. – uhoh May 07 '20 at 20:34
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    Much better! :) – William R. Ebenezer May 08 '20 at 01:56
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    @WilliamR.Ebenezer thanks! Please feel free to edit further, sometimes I don't have a good feel for how things look to other readers, especially the "hasty" ones ;-) – uhoh May 08 '20 at 03:06
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    ... so if you cross a bridge over a train track while the train is passing under the bridge, you don't see a train, because your relative motion stops it from being one. Right. –  May 08 '20 at 09:51
  • @JCRM it's the tracks that fool us; that and the fact that the cars are extended, resolved objects that are connected. These satellites are unresolved points – uhoh May 08 '20 at 09:58