#### STS

##### Active member

Hello.

I am trying to calculate the deorbit position over the surface of the earth so the shuttle can safely reach KSC or other base.

This is because SSU hasn't got the "onboard" calculations for this in OPS3 implemented yet.

I already have got some data concerning the reentry (ReA 1.282º, EI 400000ft at 4472 nm), but I am still unable to calculate the deorbit burn position. From there I will follow a path that will reach the Entry Interface, from where the OPS-304 will take on. (I understand OPS 304 is not magical, and will not take me to the runway if my ReA or vertical speed is no-go).

I am trying to calculate this through elliptic geometry but it is a real pain in the neck. I am not precisely good at maths and those calculations seem particularly complicated for me, I thought to reach the solution through calculating a transfer orbit between the orbital ellipse and a "hypothetical" ellipse or circle in which the Entry Interface Point is located.

I am trying to calculate the deorbit position over the surface of the earth so the shuttle can safely reach KSC or other base.

This is because SSU hasn't got the "onboard" calculations for this in OPS3 implemented yet.

I already have got some data concerning the reentry (ReA 1.282º, EI 400000ft at 4472 nm), but I am still unable to calculate the deorbit burn position. From there I will follow a path that will reach the Entry Interface, from where the OPS-304 will take on. (I understand OPS 304 is not magical, and will not take me to the runway if my ReA or vertical speed is no-go).

I am trying to calculate this through elliptic geometry but it is a real pain in the neck. I am not precisely good at maths and those calculations seem particularly complicated for me, I thought to reach the solution through calculating a transfer orbit between the orbital ellipse and a "hypothetical" ellipse or circle in which the Entry Interface Point is located.

I got the data for distance and altitude of EI from here: http://www.orbiterwiki.org/wiki/Intuitive_Atmospheric_Entry#Entry_Profile

And I got the ReA looking at IMFD´s map function after STS-107 deorbit and at STS-107 before EI scenarios.

This picture makes it easy but the problem begins when ellipses get involved.

Thank you very much.

And I got the ReA looking at IMFD´s map function after STS-107 deorbit and at STS-107 before EI scenarios.

This picture makes it easy but the problem begins when ellipses get involved.

Thank you very much.

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