Friday, March 19, 2010

Foot fall around Orion in the mid-day glare

Descent stage of Lunar Module 11, Orion of Apollo 16, as imaged in the harshest kind of lunar mid-day sun from only 46.81 kilometers overhead (LRO-target-Sun phase angle "f" of 7.77°). Using the NASAView program (v3.6, Jan. 2010), available from the Planetary Data System (PDS), a direct sample of the raw LROC NAC image (M113853974LE - ~51.7 cm per pixel) even a very brief exposure time of only three ten-thousandths of a second was sufficient to capture defining glare of processed metallic and man-made materials against a blindingly bright albedo of surrounding lunar surface, the Cayley Plains material situated between North and South Ray crater (8.9730111°S 15.5001889°E), north of the Descartes swirl and lunar magnetic anomaly. Though it may be the best direct views so far of Apollo 16 our first glance might mislead. Was all the rich detail of the terrain sacrificed to capture (slightly from the North) the historic artifacts of Young & Duke's expedition of April 1972? Unlike a tourist at the Grand Canyon, the LROC team can't immediately change the exposure and take the same shot again [NASA/GSFC/Arizona State University].

Not quite. After running the 400 line by 800 sample (~196 x 408 meter) area through the clumsy auto-correct feature of the open-source Paint.NET program we see arguably one of the best views yet of astronaut footprints on the lunar surface. The dark circle brought out, around Orion's descent stage is from descent exhaust but mostly from foot-fall, almost obscuring the larger vehicle and virtually invisible in the raw image higher above. As it is, the trails taken by Young and Duke, exposing less-space-weathered material below the immediate surface, trace out and around Orion's landing struts and the other objects nearby like the U.S. flag, camera, and ALSEP [NASA/GSFC/ASU].

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