A few strong sensors and high speed network connections, range, a few pilots and IT folks.
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The aircraft (below) already has an MX-15 sensor installed beneath its rear fuselage, plus a large fairing above its cabin to accommodate satellite communication equipment. ... Other systems could include a line-of-sight tactical common data link, self-protection equipment, signals intelligence-gathering sensors and a maritime search radar, all integrated with L-3's onboard processing, exploitation and dissemination system.
Fraction of the costs of a full blown MPA. The specialist are on the ground, not in the air.
PICTURE: How L-3's re-nosed 'Spydr' King Air will look