Hello!
My fun these days is a trans-martian injection delivered with the help of TransX MFD. I did menage to catch orbit around Mars, it was fun and learning experience (Titan, here I come!
but there are several issues I'd like to address: basically, I want to wrap my mind around interplanetary travel and how physical concepts relate to TransX controls and variables. Let's consider a simple TMI; what I want to do is to make precise burn so I enter plane defined by three points: escape position, encounter position and sun's center of mass. It is self-evident how this relates to prograde velocity, change plane and ejection date. What I find far more peculiar is the escape stage; at a certain point on circular orbit we make a burn that transforms it to a hyperbola which, as we travel to the border of Earth's sphere of gravitational influence, is more and more perturbed by Sun's gravity so ultimately it "transforms" to an ellipse around the Sun on which we travel on. Let us assume, for simplicity, that we have Dirac engine so the velocity gain is instantaneous; it may kill everyone on board, but will make math more simple Anyway, these are the questions:
* Is the description correct?
* If so, what is approx. distance to border of Earth's sphere of gravitational influence (ESOGI)?
I'm well aware there is no sharp boundary, but just as an estimate ...
* Is asymptotic direction of velocity of unperturbed hyperbola any useful at defining ellipse around the Sun?
I note that after breaking ESOGI, exit speed should be at larger angle to ecliptic than travel plane (sun-esc-enc) because it will add as vectors to Earth's velocity. I state the last question because the exit speed is not much larger than 2nd cosmic speed, therefore defining quite a "tight" hyperbola which suggests (at least to me) that near asymptotic direction of velocity will be assumed by the ship relatively fast. This could be checked, but I'm too lazy to do polar derivations
If answer is yes, then there is a whole family of hyperbolae that will make just as good TMI; so
* Is Ejection Orientation the degree of freedom by which we choose one hyperbola from this family?
Of course, different hyperbola will define different ellipse around Sun, but it seems to me that error distance after 1/4 cycle can at worst be 30-50M.
I wanted to ask another thing, but I forgot it at the moment ... anyway, thanks for any input!
My fun these days is a trans-martian injection delivered with the help of TransX MFD. I did menage to catch orbit around Mars, it was fun and learning experience (Titan, here I come!
but there are several issues I'd like to address: basically, I want to wrap my mind around interplanetary travel and how physical concepts relate to TransX controls and variables. Let's consider a simple TMI; what I want to do is to make precise burn so I enter plane defined by three points: escape position, encounter position and sun's center of mass. It is self-evident how this relates to prograde velocity, change plane and ejection date. What I find far more peculiar is the escape stage; at a certain point on circular orbit we make a burn that transforms it to a hyperbola which, as we travel to the border of Earth's sphere of gravitational influence, is more and more perturbed by Sun's gravity so ultimately it "transforms" to an ellipse around the Sun on which we travel on. Let us assume, for simplicity, that we have Dirac engine so the velocity gain is instantaneous; it may kill everyone on board, but will make math more simple Anyway, these are the questions: * Is the description correct?
* If so, what is approx. distance to border of Earth's sphere of gravitational influence (ESOGI)?
I'm well aware there is no sharp boundary, but just as an estimate ...
* Is asymptotic direction of velocity of unperturbed hyperbola any useful at defining ellipse around the Sun?
I note that after breaking ESOGI, exit speed should be at larger angle to ecliptic than travel plane (sun-esc-enc) because it will add as vectors to Earth's velocity. I state the last question because the exit speed is not much larger than 2nd cosmic speed, therefore defining quite a "tight" hyperbola which suggests (at least to me) that near asymptotic direction of velocity will be assumed by the ship relatively fast. This could be checked, but I'm too lazy to do polar derivations
If answer is yes, then there is a whole family of hyperbolae that will make just as good TMI; so
* Is Ejection Orientation the degree of freedom by which we choose one hyperbola from this family?
Of course, different hyperbola will define different ellipse around Sun, but it seems to me that error distance after 1/4 cycle can at worst be 30-50M.
I wanted to ask another thing, but I forgot it at the moment ... anyway, thanks for any input!
