The world of Ukrainian missile defense advocates was euphoric when, during the early July NATO summit in Ankara, Turkey, U.S. President Donald Trump stated he was willing to give Kyiv “the blueprints” needed to build its own Patriot missiles. But only the high-end missile of the different effectors that the US Patriot system can fire, the PAC-3 Missile Segment Enhancement (MSE), can take down Russian-made ballistic missiles. In a missile attack last Wednesday, not a single one of the 24 ballistic missiles fired by Russia at the Kyiv region could be intercepted. The MSE missile does not even have an explosive warhead because it does not need one. It’s All in the SeekerWhat caused the US to “walk back”, as it is being labeled, Trump’s promise of a month ago are the issues surrounding the MSE missile’s Ka-band active-homing radar seeker head.