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9

The disk is in no sense in orbit if it stays above a fixed location on Earth at such a low altitude. Basically the thrust would need to do all the work to hold it up against Earth's gravity. So such a disk has an area of $5000^2\pi\ \mathrm{m^2}$ and so a mass of $2.5\pi\times 10^8\ \mathrm{kg}$ with your estimate for the area density of the disk. It would ...

6

You are describing the Local Vertical Local Horizontal (LVLH) frame of reference. It is used to describe the orientation of the spacecraft in relation to the Earth's surface. For example, if you wished to point an instrument at the point on the Earth directly below the spacecraft, the craft would fly in a constant LVLH attitude. But its inertial attitude ...

3

Taken purerly in ideal terms, a satellite that has no additional forces acting on it will keep doing whatever it was previously doing rotation wise, but that may in fact be a carefully set slow rotation that keeps an antenna or camera facing earth for comunications or earth science, or fixed if it was a telescope watching a distant star. So either of your ...

3

The only source I have found says the magnitude is around 6, which is pretty typical of a satellite of the size and distance from Earth. What I speculate happened was that the orientation of the solar panels right after launched caused a flare to be seen from the ground, which was quite a bit brighter than a typical satellite. It was even more noticeable as ...

2

To expand on @gremlinWrangler's mention of tidal effects radiation pressure YORP let's not forget Spacecraft Aerodynamic Torques NASA SP-8058, see also Passive Aerodynamic Stabilisation of Low Earth Orbit Satellite Bak, T. & Wisniewski, R., Spacecraft Guidance, Navigation and Control Systems, Proceedings of the 3rd ESA International Conference held ...

2

This started out as a comment on 3), but this should be a rough answer by now. This means exactly what it says on the tin. They have been observed for so long that we have accurate enough data on them to not confuse them with other objects. They are not in the process of being identified as belonging to a specific launch. The cracks in the surveillance ...

1

The generic term seems to be "positioner", sometimes with adjectives like "trolley positioner" (The) Aronson Trolley Positioner...was specially designed by NASA to assemble and “Float on Built-In Air Pads” a 2 billion dollar spacecraft that was launched in late December 1999 or "rotary positioner". Standard commercial items exist, but perhaps the ones ...

1

After the discussion here I finally switched to measuring the integrated density of the complete sat trail, subtracted background noise and compared the result against the known star HD 211599 (mag 8.87). Here I also subtracted the background noise. The Excel formula is attached. For Starlink 29 I calculated a magnitude of 7.59 near the horizon. Nice :-)...

1

Slowly getting the facts together ... I was measuring Starlink 29 the other night with a Newton 8' f5 on an iOptron CEM60 mount. Used Skytrack (only availabe for iOptron) for sat tracking. I plate solved the image in AstroimageJ and found four good stars nearby the satellite trail. The satellite was 12 deg above the horizon only. Looked up the ...

1

If you want a complete answer about how SGP4 (or SDP4) does it, you should read form the original source: The Space Track Report #3. For the actual theory behind, you should read the references by Hujsak and Hoots, for which I could not have access. During the description of SDP4 routines, it says: "At this point SDP4 calls the initialization section of ...

1

The BBC News article Satellites to monitor whale strandings from space describes the use of the WordView-2 satellite to image mass standings of whales, and references the recent Open Access (non-paywalled) paper in PLOS ONE Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia which ...

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