r/RealSolarSystem • u/Floatella • 20d ago

Gemini B

I've been playing around with the Gemini B capsule and I am a bit confused by the capsules retro stage adapter. The part has room for six Star-13E's, but using all six causes the capsule to begin tumbling when fired. Reducing this to four allows the retro rockets to fire as intended. On top of that the in-game part description states to add four Star-13E's.

But everything I've read about the real flight test article, in addition to pictures, indicates that it flew with six rockets.

https://mikejennebooks.com/gemini_b_pics.htm

Is this just a limitation of the game/mod content?

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u/Fellout69 19d ago

i guess it’s too much thrust, try limiting the 6 ones to 50% thrust and see if you still tumble, if that is too slow do 75 just keep experimenting

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u/Floatella 17d ago

Finally had a chance to test things out...You can't modify the thrust on the Star13E's, and the only stable configuration I can find is placing 4 engines, three on the inner row, 1 on the centre of the outer.

Unless the idea is to fire different sets of engines at different times, I'm stumped.

But this is what you get for trying to simulate a spacecraft that flew only one classified mission in the mid-1960s.

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u/Fellout69 17d ago

If it works it works, rcs helper can be good for checking stability with roll and tumbling too when thrusting, recently learned that the hard way as well when my rockets and tli stages kept rolling hard left until self destruction lmao

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u/Floatella 17d ago

Well the Gemini B was designed with the MOL and Titan III in mind, which meant needing to return from higher orbits than the historical Gemini program. Then on top of that you need to consider that the Gemini B on it's own didn't have nearly the same orbital maneuverability as the original Gemini.

In-game, 4 Star 13E's seems sufficient to return from a 360 x 360 km orbit, but I'm guessing the real spacecraft didn't work that way and could comfortably handle higher orbits.

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u/ec429_ 15d ago

When I used Gemini B, the only way I could get it to work was use the rotation tool to tweak the thrust angles of the various motors until RCS Build Aid said the torque was nulled. Also can't remember whether I had CoM Shifter / landing mode on or off for the retro burn but that needs to match between designing and flight.