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I am currently researching the feasibility of setting up a coilgun that launches Cubesats for a paper. 1 cubesat per launch total payload mass <100kg.

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    $\begingroup$ You will want to specify a duration also. Some artillery rounds can sustains much more than that, for a very short duration (and also have some electronic) $\endgroup$ – Antzi Jan 22 '19 at 8:44
  • $\begingroup$ @Antzi I suspect the goal is to go to 7.8 km/s. If the acceleration is 100g, it happens in around 8 sec. $\endgroup$ – peterh - Reinstate Monica Jan 22 '19 at 9:06
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    $\begingroup$ While it may be possible for 1kg nanosatellite and 1dm^3 nanosatellite, I think it would be quite difficult for a 1kg 1dm^3 nanosatellite. Any structural empty space would result in heavy damages due to the acceleration; the thing should be full and filled with a quite durable material that will likely be more dense than 1kg/dm^3. Another thing to consider is massive eddy currents induced by the coilgun. And you still need a propulsion to circularize. $\endgroup$ – SF. Jan 22 '19 at 9:55
  • $\begingroup$ Protection against 100 g is not possible anyway, only against very short peaks higher than 100 g. You may use very rigid cases, very strong PCB boards but you need all electronic components used certified for about 120 to 150 g. If you want to launch from ground to orbit per coilgun, you need an excellent heat shield to pass the densest parts of the atmosphere at abou 8 km/s. But a circular or elliptical orbit above the atmosphere is impossible with only one coilgun acceleration. $\endgroup$ – Uwe Jan 22 '19 at 12:15
  • $\begingroup$ @SF A 1kg nanosat should, very roughly speaker, be able to stand 100g if it can stand a heavy person standing on it $\endgroup$ – Steve Linton Jan 22 '19 at 14:54
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It is certainly possible to mount electronic components to survive 100G, see HARP which had instrumented rounds firing at thousands of G. The fundamental step is to mount everything in epoxy with the aim to have everything be roughly the same density with no air gaps or denser sections to keep forces in direction of motion, not attempting to displace things sideways which tends to break electrical connections.

This can work for a single function sensor but some interesting complications making a useful cubesat fly this way. Optical sensors for example generally need a void for the lens assembly to work, so do many solid state MEMS devices and crystal oscillators . Power will also be complicated, since most high density battery chemistries are high density by virtue of mechanically minimalist design and loose a lot of capacity being made robust enough to not crumple to one end of the cell and short out. High performance solar cells are also not noted for robustness and would need to go on the outside of the chassis, where they would tend to sag away as the chassis shortens during acceleration.

So a 100G target is provably possible, but the question is how useful the resulting electronics is at actually being a functional satellite, especially with probably a much lower electric power collection and storage budget compared to a rocket lifted cubesat of the same size.

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  • $\begingroup$ If everything is mounted in epoxy, heat may be a problem. $\endgroup$ – Uwe Jan 22 '19 at 13:12
  • $\begingroup$ @Uwe, agree but could not work out if the problem would be heat build up from the epoxy, or excessive cooling due to the very solid metal chassis pulling heat away so ended up editing it out. Certainly just grabbing a standard cubsat electronics bay and filling it full of epoxy is a quick way to overheating. $\endgroup$ – GremlinWranger Jan 22 '19 at 14:00

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