How to Complete The Radix Module Mission at the beginning of the Hybrid Career?!?!?!?

So when you start the hybrid Career Mode there are three different tests from each of the main boss's from the original career have they're own tests for you to pull off and one of them is to start a space station by bringing the radix module to orbit with a 300km orbit and a 50° inclination and after you release the module the final step I've found completely impossible to complete somehow which is Deorbit your booster which translates to Periapsis<78.1 Which That is no problem at all but no maatter how I go about this step it never checks the last step to this mission and it is absolutely inferiorating PLEASE HELP AND FIX