23

I found it. It was NOSS 3-1, a satellite pair. Found it through heavens above. The pair also explains the apparent tumbling. However, it seemed much brighter than 4.1, but it‘s definitely it.


5

Several of the early satellites, including the first US satellite, Explorer, used black and white stripes to control the satellite's temperature by adjusting the a/e (absorptivity-to-emissivity) ratio. (Ref 1 and image below) The white strips have low absorptivity and low emissivity while the black stripes have high absorptivity and high emissivity. The ...


3

There are many conflicting requirements: gain of the antenna size of antenna directionality of antenna. bandwidth To make antenna efficient you want it to have a narrow beam to direct most of the energy to the satellite. This implies your antenna will be highly directional. For a hand held device it is almost impossible to aim the beam reliably when the ...


3

SpaceX has been launching Starlink satellites in large quantities and a recent launch may be the satellites you've seen. On release they have close spacing and slowly separate to the appropriate orbits. According to the website, Heavens-Above, the most recent launch was Starlink 5 on 18 March 2020. The site describes the visible satellites as "string of ...


3

Let me put this in a different frame. First recall that magnetic fields also store magnetic energy: $$ E_{mag} = \int_V H. B\, dV $$ Now, from Lagrangian mechanics, note that: $$ L = U-V = E_{mag}+E_{grav}-\frac{mV^2}{2}-\frac{\omega^TI\omega}{2} $$ And let's forget some dissipative effects and the angular terms for now. Recalling Euler-Lagrange's ...


3

Dipole-dipole repulsion The drawing depicts the right idea; if you hold two parallel magnetic dipoles close together there is a strong repulsive force. If you let go, they will fly apart. In order to imagine what would happen if this was in Earth orbit, let's make the horseshoe magnet an electromagnet. It's the same shape but instead of being made from ...


3

No. What can be done with a magnetic field in Earth's orbit is to torque, or rotate the satellite. But for propulsion of some kind, you would actually need to have some kind of a varying magnetic field, and a tether of some kind. This website talks a bit about how such a thing could work.


3

Very likely you have seen Starlink Satellites. A view we all have more often in the future... Assuming you mean 0450 local which is more or less greenwich-time which does not differ much from UTC. Just one thing: They are around 100 km appart ;-) Plot for 02/03/20 0450hrs, Bradford, West Yorkshire, UK. click for full size view


2

In-the-sky.org doesn't show anything that quite matches your specification. There was an H-2A rocket body (i.e. upper stage) overhead at 7:46 going from NE to ESE; there was an SL-16 (Zenit) rocket body a couple of minutes later going ESE to N. Tumbling rocket bodies can vary considerably in brightness.


2

"The answer is always thermal control" San Marco-1 The satellite had black and white longitudinal sections painted on its surface for thermal control. NASA Space Science Data Coordinated Archive / San Marco 1 Asterix-1 This was the first French satellite, launched in 1965. It's painted with stripes as a form of temperature control - the black ...


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