April 20, 2004

On the Moon

Image Credit: Phillip Stooke

On the Moon This panoramic image shows the Surveyor 3 landing site, later visited by the Apollo 12 astronauts. The bland appearance is largely the result of a high sun angle, but dust on the camera mirror also reduced image quality. Surveyor 3's small vernier landing rockets did not shut down as planned just above the surface, causing the spacecraft to land and take off again twice. Finally the flight controllers sent a command to turn off the verniers and Surveyor came to rest, but dust thrown up by the rocket exhaust contaminated the camera mirror and may have partly clogged the pointing mechanism. As a result the images were reduced in both number and quality, and the camera could not move fully to the left to complete the panorama. At the bottom of the scene two trenches are visible, dug by a robotic arm which is not visible here. This was the first operation of a remotely-controlled arm ever undertaken on another world. Surveyor 3 landed April 20, 1967. Technical Details: The image was compiled by scanning and combining sections of assembled panoramas at the Lunar and Planetary Laboratory, University of Arizona. The raw panorama, like all Surveyor panoramas, was severely disfigured by frame-to-frame brightness differences, regular patterns of 'reseau' dots on every frame, and other artifacts. These were laboriously removed frame by frame - this is not a process that lends itself to automation. The defects were not removed over areas of the image which cover the spacecraft, so the extent of the initial problem can be seen in those areas. The entire procedure, performed in Adobe Photoshop, took three months. This image was prepared for a forthcoming atlas of lunar exploration. Related Links: Phil Stooke website Surveyor 3 Mission Yesterday's LPOD: Elger's Journal - or Goodacre's? Tomorrow's LPOD: A Boisterous Astronaut

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Author & Editor:
Charles A. Wood

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