# Reasonable argument of periapsis?

My intuition for orbital parameters is still poor, so I'm wondering if someone can tell if my argument of periapsis seems reasonable.

I'm simulating a launch from Kennedy (28.1 deg latitude, -80.6 deg longitude) onto the orbital plane of the ISS (51.6 deg inclination, -104.5 deg longitude of ascending node, measured in earth-centered inertial frame).

I hit my target inclination and longitude of ascending node at the exact moment of orbital insertion, along with velocity, altitude, and eccentricity targets. I specified my target altitude, velocity, and flight path angle to get a true anomaly of 0 deg at insertion, which means I'm inserting at periapsis.

My argument of periapsis at insertion is approximately 52 deg. Does this number seem reasonable?

I imagine the 52 deg should include a small angle from the launch pad to the insertion point plus a larger angle from the ascending node (in the equatorial plane) to the launch pad at 30 deg. Is it reasonable that the total angle should be 52 deg? I'd imagined it would be smaller, but is this right?

• You’re inserting into a somewhat circular orbit. Isn’t argument of periapsis assumed zero in this case? You or I may have missed some info here that constrains this question. Do you mean your ascent trajectory intercepts the Earth surface at 52 degrees of true anomaly behind the insertion point (or maybe mean or eccentric anomaly)? – CourageousPotato Mar 21 at 9:49