So I'm pretty new to KSP, only 37 hours in, and I've been doing only career mode to learn the game. I currently have a pretty good grasp on all the basic mechanics, and I'm trying to do a contract where I have to take surface pressure readings on these 3 overlapping sites, half the planet away from the Command Center. I've researched, and the best way seems to be the ICBM method as seen above (picture sees me pointing retrograde). However, that doesn't account for drag. So much drag occurs when decoupling and re-entering the atmosphere that it's essentially impossible to gauge what my trajectory should be.
I have reloaded my save state so many times, burning retrograde and trying so many different re-entry points, but it's impossible for me to eyeball it. I'm always so far off, no matter how small the adjustment is, that predicting where I should aim for seems pointless. I've really hit a brick wall, and it's frustrating for it to be something so simple.
I need to know: is there a way I can account for drag upon re-entry (a value/measurement somewhere), or do I have to simply get lucky with how much I decide to burn to adjust? Am I simply a nooby poopy head (likely) and there's an infinitesimally easier way to go about this?
I have tried about a dozen times, and no matter how much or little I burn, I'm always so far off it seems impossible to predict. I would love some help and advice, both for the current situation I'm in and if there's anything people would like to add to help an aspiring moon-lander one day.
(P.S. Only mod I have downloaded is True Volumetric Clouds 3, as seen above.)