ASRAAM, the CASTOR/ASTOR project had a very long gestation. It started off as a Cold War BAOR requirement (CASTOR), and was then heavily influenced by the apparent success of JSTARS in GW1 and political directives. The competition was quite broad (including an offer of refurbished U2s), and, I imagine, there was plenty of Army/RAF ‘debate’ over requirements, manning and what platform to select. To me, it looks like the RAF has willingly traded a ‘joint’ asset to secure Protector, RJ, P8 and E7 funding in the medium term - and will doubtless claim that each platform can do part of the Sentinel’s role. Interesting potted history here;
https://www.raytheon.com/sites/defau...tinel_Book.pdf