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Reading about the Ultralight Starshade Structural Design, It seems some solution among others could be an umbrella based concept

Since the starshade has to be roughly 100m in diameter, one could imagine an umbrella like structure, whose 50m single piece ribs are folded against the cylindrical body of the launch vehicle (like an umbrella) during launch up to orbit.

Are there examples of unprotected or partially unprotected payloads that went to orbit, what is a rough picture of the stresses on the lauch vehicle's skin during ascent?

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Partially: Skylab (look how that turned out), Proton (the high-energy astronomy satellites, not the rocket), the MOL (Manned Orbiting Laboratory) demonstrator, and of course Mercury, Dragon (some sort of cover on the very tip). You might want to count boilerplate versions of spacecraft designs too (arguably the MOL dummy), which might mean the Pegasus(es) count. Pegasus had protection on the things they cared about.

Unprotected: Gemini (NO launch escape hardware on the front), Shuttle (look how that turned out), and therefore Buran. The Soviet FOBS might count, depending on whether you consider that orbital, or technically orbital or whatever. If you hadn’t mentioned orbit, the list expands to all manner of hypersonic flights.

On anything forward- or close-to-forward facing, aero heating is as much of an issue as air load. Early ICBMs often (but not always) had partially or wholly exposed warheads because they had overdesigned heat shields anyway, so who cares- skipping a fairing saves mass and separation failures. Same with Mercury/Gemini to a lesser extent, plus Shuttle’s (underdesigned, in terms of systems engineering) heat shielding.

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  • $\begingroup$ great examples thanks, conversely I wonder why sputnik1 was covered by a fairing when its shape was ideal to get rid of it $\endgroup$
    – qq jkztd
    Aug 3 at 14:23
  • $\begingroup$ The actual Shuttle payloads were enclosed in its payload bay. $\endgroup$ Aug 3 at 21:17
  • $\begingroup$ Except that the Shuttle orbiter itself was one payload- Carter was cowed into sparing the program with the prospect that ‘killing manned flight’ would be used against him. Three senators flew; note that that’s one senator per deep-space probe, a rather pathetic ratio if science, not politics, is supposed to matter. Then add the foreign freeriders. The ability to do PR work for State might not have been a design requirement, but it happened anyway. If the orbiter was not a payload, then that implies a Shuttle-C, like Energia. No Shuttle-C ever happened, because… $\endgroup$ Aug 4 at 14:12
  • $\begingroup$ Typical Soviet practice (which just so happened to work out for some US groups) was a sphere, thus implying a fairing for any significant radius. All of us eventually figured spheres did little, but cost more than plane-parallel. $\endgroup$ Aug 4 at 14:16

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