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About JoeSchmuckatelli

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  1. Heh my edit crossed your post. I'll read more about this and return better informed. Again, thank you - finding this very informative
  2. Hmmmm. Gonna have to think about this for a bit. So... Are we using Newtonian physics for even far away missions like New Horizons? I remember reading a Scientific American article years ago about utilizing the geodesic for ultra low energy transfers between planets... I figured that meant we were using Einstein's theories to figure out orbital mechanics - but what you write also jibes with something else I've read about Newton's work being accurate enough for everyday physics problems. (by which I thought the writer meant terrestrial ballistics - but not interplanetary space flight). So what makes Mercury a special circumstance? EDIT: wait... I remember reading something about the transit of mercury being a big issue: I'll start there. Thanks for the discussion /answers this far!
  3. Hmmmm. Okay... I can accept that. The bold part of your response has my attention: Why does orbital mechanics have nothing to do with curved spacetime?
  4. Quibble - the precession is about 26,000 years, so while I grant you are correct it does not resolve my issue. If you think about those coin donation funnels; if you were able to get a spinning top to drop out of the chute it would generally follow the same path as the coin, and the axial tilt would precess with every orbit. But the earth's axial tilt does not precess with every orbit. Wouldn't it, though if it's orbit around the sun were a result of curved spacetime?
  5. FYI - as I understand the Eddington observation as a confirmation of Einstein / Minkowski (curved spacetime)... Photons (aka light) are massless and travel in a straight line and could not be affected by gravity if gravity is created by a particle. But if gravity is a curvature of spacetime, a massive object (like a sun, black hole or galaxy) will warp spacetime and while the photon travels in a straight line - the space through which it travels is curved, giving rise to observed phenomenon such as gravitational lensing. It's trying to correlate the gravitational lensing idea with what we observe with planetary orbits that's driving me nuts
  6. It's defining gravity as a warping of spacetime that I'm struggling with. Tidal locking makes sense to me given mass irregularities if gravity is a particle effect, as well as if it's an effect of warped spacetime. But once you add spin to an object the examples (ie planets) seem to conform more to the particle idea than the curved space idea. I'm certain that I'm not the first to see this... And I hope someone can help me understand why the apparent discrepancy is not a discrepancy at all
  7. Yes - which is why earth's inclination angle keeps us oriented to Polaris regardless of where we are in the orbit. I can envision this with gravity resulting from a particle (like a boson), but if what we perceive as gravity is merely an effect of the curvature of spacetime... Why doesn't the earth's axial tilt precess throughout the year? If the earth is traveling in a straight line - but the space it is traveling through is curved, wouldn't the same hemisphere be angled towards the sun the whole time?
  8. You are correct and I misspoke... With the earth's spin it retains the inclination angle through it's orbit (hence the seasons). But as I try to imagine curved space I would guess that the inclination angle might behave differently - rather than the northern hemisphere angled to the sun in summer and away in winter... That following the curve of spacetime would keep one hemisphere angled towards the sun year round.
  9. So... Yes. And yes! While I haven't played KSP for a while, I've known that it's absolutely possible to keep a space object oriented however we want it. I've also presumed that orbiting objects maintain their inertial attitude. What I'm struggling with is more abstract. I saw the full eclipse this year. It got me to thinking about the Eddington experiment that confirms Einstein - Minkowski space time for most folks. Under this framework gravity isn't a force like magnetism but a curvature of spacetime where objects in space (including light) move along 4 dimensional geodesics. In other words, orbits around massive objects are defined /caused by the the curvature of spacetime. So... Okay. But. If this is truly correct... Why is it that things in orbit maintain the inertial attitude? The earth maintains its internal attitude around the sun (hence the seasons) just as a refrigerator would around the earth. If spacetime is truly curved - how is inertial attitude maintained at all? Why doesn't an orbiting object move more like a car on a track? (or orbital rate attitude?)
  10. Thanks! Getting the terminology correct is always a better way to phrase a question (hell even finding out what the terminology is is crazy hard sometimes!)
  11. Thanks! This part is what I was looking for. It makes sense. ... Although, when I started reading about Minkowski space my head twisted up and I began to wonder whether curved space would make an object in orbit follow the curve... Ah heck I can't describe what I was thinking! Gracias!
  12. Thanks - that answers some of my questions. I guess what I want to know is how an orbiting object behaves differently from a plane. I know that a plane in suborbital flight is kept aloft by lift, and as it travels around the world its bottom will always be pointed 'down' / parallel to the surface (level flight). But a space craft is in a ballistic free fall, going fast enough to keep missing the planet. As such, I'm trying to figure out whether it would circle the earth like a plane (nose forward the whole time) or if it would maintain the orientation it had when it entered orbit - ie if it entered orbit with the belly towards the sun - would it keep that orientation throughout the orbit? Where you write 'depends on the orientation mode chosen' - I can infer that mission control could do whatever they wanted - but what is the 'natural state'? Or what would a defunct satellite or even a refrigerator do once in orbit? Would it be tidally locked or show the same face only when in the same part of the orbit?
  13. I've read that as the shuttle orbited the earth it kept the bay doors toward the surface and the bottom of the shuttle toward the sun. I believe the reason for this was to keep the thicker shielded bottom of the shuttle between the crew and the giant radiation hazard we call the sun. Similarly, I've read that ISS cupola faces the earth to give the crew a view of home, and I've seen night and day pictures of the earth taken by crew of the ISS. The question I'm curious about is this: are the bay doors of the shuttle and the cupola of the ISS oriented on the surface during a full orbit? (i.e. Once in orbit, does the craft maintain its orientation to the surface like a plane in flight, and/or does it require gyros to keep the window /bay facing the surface?) The problem I have is that part about keeping the bottom of the shuttle between the crew and the sun. I'm wondering if the shuttle bay doors were open to the day side during the sunward part of the orbit, but open to the darkness of space while on the night side of the planet. Ultimately, what I would like to know is whether keeping one side of a spacecraft facing the surface requires gyros (or whatever), or whether, once in orbit a craft would 'naturally' fly 1/4 of the orbit backwards, then 1/4 nose to the earth, then 1/4 forward and the final 1/4 with the tail pointed to the earth. Thanks in advance for any info!
  14. This relates to a couple of past threads where I learned about using Tylo or Laythe to get a Joolian orbit without massive expenditure of fuel. The clock has been ticking, and I'm getting ready to do my burn to achieve a Tylo encounter (for the second try). I've placed a maneuver node - and to get the proper encounter I need (using a NERV) a 25 second (73 m/s) burn - and the burn requires mostly Radial Out, a middling amount of Retrograde and a touch of Normal. This places the dark blue maneuver marker about 5 degrees off the Radial Out marker. On my first attempt I lined up on that marker and fired the engine for the required time... and completely lost the encounter. Now - what I did not do was follow the marker when it started to wander - just kept my orientation where it was originally. So - the reason behind the question - I've seen some guys manually 'feather in' their burns - firing aimed at the Radial Out for a while, then rolling to Retro for a squirt or two, then Normal and back to Radial Out to get the alignment they want, all the while zoomed in on the planetary system to see the effects of their burns. Seems fiddly - but it obviously works. The main question is - for a guy with a passing understanding of what is going on - is that a better method than 'aiming at the dark blue maneuver marker and hoping the computer lined me up correctly. And a final question: should I try to follow the blue marker when it wanders?
  15. Grumble grumble grumble... I have a knuckle dragger solution that works. Now you guys are telling me my baby ain't as pretty as I thought she was! (Grin) Okay - back to the drawing board. I guess I'll play with some SRBs at lower stages as well - I've been burning liquid fuel + Ox at the cyclic rate. Thanks for the input folks - every time I post on here... I learn something new.