When high speed high altitude target is going on you with "Parameter" less than 10 km, missiles should climb very fast and in "T/T" or "I-187" modes it is very difficult when the target is aproaching... You should launch 3 in a row, when SR-71 is about 80-90 km from you and you should got it between 35-40 km from you... Reading your post i think that you launch too early or too late..., and you see your missiles going down on the left indicator just before the target (you shot too early), or if they do the same, eeven when target is in range - means you shot too late....