Since much of the information presented in this paper is my interpretation of earth observation developments during the past twenty years, it is well that I offer some qualifications. I am an engineer of the "old school" with degrees in aeronautical and electrical engineering. I say old school because it was hammered into my head at Georgia Tech that engineers do useful things or they starve. I have been concerned during my twenty-five years of R&D experience in airborne instrumentation developments that the output of results of practical use to society has been minimal. I have become more enthused in the past nine years from my participation in the development of multispectral scanning and discrimination techniques. I believe we have finally developed a useful new remote sensing tool. As you might imagine I am biased toward aircraft as a widely useful earth observation platform for optical scanners. However, I see the merit of other platforms and I am an advocate of using appropriate tools for a particular job.
Philip G. Hasell, Philip G. Hasell,
"Tie Continuing Role Of Aircraft In Earth Observation Projects", Proc. SPIE 0051, Scanners and Imagery Systems for Earth Observation, (1 March 1974); doi: 10.1117/12.964573; https://doi.org/10.1117/12.964573