As to be expected, Ralph is no ordinary camera. Leonard David stresses the difficulties faced by the company contracted to produce the instrument, Ball Aerospace, in designing and manufacturing a sensor that could meet NASA's specifications. Among the problems were the low power produced by the New Horizon's electrical distribution system (only 28 watts was available for scientific instruments), that camera also faced 9 years of coldness and hard radiation, and that the light reflected from Pluto's surface is a 1,000 times dimmer than Earth’s.
The Ralph camera sensor is far more sophisticated than one would expect. After all, NASA does not simply bolt on a Nikon to a space probe and expect it to work. Jim Baer, Ball Aerospace’s optical engineer for the program, describes Ralph’s camera suite as consisting of three black-and-white along with four full-colored imagers that provide a telescopic resolution 10 times better than the human eye. To achieve the best possible focus, the system was designed so that all the components would contract from the cold of space at the same time. The imager was so well designed that Ralph was able to achieve an optical resolution of 250 meters per pixel.
Leonard David has written a highly informative article that describe not only the remarkable capabilities of the Ralph sensor, but also the engineering ingenuity and obstacles that the designers faced when developing this amazing instrument.
Resource:
David, L.
(2015). Meet Ralph, the New Horizons
Camera Bringing Pluto into Focus. Retrieved from http://spacenews.com/new-horizons-about-to-bring-an-unknown-world-into-sharp-focus/
