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Hello all! I've been obsessed recently about doing a lot of math on paper to determine the optimum variables for orbital maneuvers. A couple things have been bugging me though, and no amount of research has given me a concrete answer.
In the DeOrbit program within the BaseSync MFD (v2.3), you have to enter values for "Reference Altitude", "ReEntry Angle", and "ReEntry Anticipation Angle" for the program to predict accurate burn times and locations. I understand that the Reference Altitude represents the altitude above the celestial body's surface at which point significant atmospheric effects are felt by the de-orbiting craft (80 km for Earth). I also understand that the ReEntry Angle is the angle at which you descend from your initial orbit towards your target landing area. And, I understand that the Anticipation Angle is the angle between your radial position at the point you intercept the Reference Altitude, and the radial position of the target landing area.
What I do not understand however is how to calculate appropriate values for those last two. Yes, I know that ~.7 degrees is a "good" reentry angle for the DGIV, but why and how can such a value be determined for any craft (I'm assuming based upon information such as lift coefficients and vessel mass). As for Anticipation Angle, I am fully lost after seeing so many people use so many different values. I've mostly seen 45 and 16.5 degrees. 45 seems to me like a very long distance from your target base to be ripping through atmosphere. Can someone give me some info on how to either calculate these two variables or at least how to choose them wisely?
Thank you in advance!
In the DeOrbit program within the BaseSync MFD (v2.3), you have to enter values for "Reference Altitude", "ReEntry Angle", and "ReEntry Anticipation Angle" for the program to predict accurate burn times and locations. I understand that the Reference Altitude represents the altitude above the celestial body's surface at which point significant atmospheric effects are felt by the de-orbiting craft (80 km for Earth). I also understand that the ReEntry Angle is the angle at which you descend from your initial orbit towards your target landing area. And, I understand that the Anticipation Angle is the angle between your radial position at the point you intercept the Reference Altitude, and the radial position of the target landing area.
What I do not understand however is how to calculate appropriate values for those last two. Yes, I know that ~.7 degrees is a "good" reentry angle for the DGIV, but why and how can such a value be determined for any craft (I'm assuming based upon information such as lift coefficients and vessel mass). As for Anticipation Angle, I am fully lost after seeing so many people use so many different values. I've mostly seen 45 and 16.5 degrees. 45 seems to me like a very long distance from your target base to be ripping through atmosphere. Can someone give me some info on how to either calculate these two variables or at least how to choose them wisely?
Thank you in advance!