The Cassini spacecraft on Saturn and the Messenger spacecraft on Mercury are taking images of Earth in July 19, 2013. From their vantage point Earth will be just a few pixels, but these are rare events. Only Voyager, Cassini and Messenger have taken pictures of Earth from deep outer space before. However, not only these two spacecraft will be taking pictures of the full globe of Earth on that day. The GOES East and Meteosat meteorological satellites have similar view perspectives as Cassini and Messenger, respectively.
To commemorate this event we will try to generate satellites images of Earth near the moments the pictures from Cassini and Messenger are taken. We have to accurately combine the satellite images, which are in black and white, with color information to generate true-color images. Our plan is to create a composite wallpaper with the Cassini and Messenger faraway images together with the Earth closeups.
Figure 1. Simulated view of Earth at the moment of its picture from Cassini on Friday, July 19, 2013 between 5:27 to 5:42 PM EDT (21:27 and 21:47 UTC). Here shown exactly at 5:27 PM EDT. The GOES East satellite has a slightly west-displaced view of Earth than Cassini at the moment of the picture. Credit: NASA Solar System Simulator.
Figure 2. Simulated view of Earth at the moment of its picture from Messenger on Friday, July 19, 2013 and Saturday, July 20, 2013 at 7:49 AM, 8:38 AM and 9:41 AM on both days (11:49, 12:38 and 13:41 UTC). Here shown exactly at 7:49 AM EDT. The Meteosat satellite has a very similar view of Earth as Messenger at the moment of the picture. Credit: NASA Solar System Simulator.
Figure 3. Actual image of Earth from space by the GEOS East meteorological satellite taken on July 18, 2013 at 5 PM EDT. Color of the image was synthetically incorporated from NASA Visible Earth imagery using the PHL's SER software. This image was created to test our software in preparation for the event. Click for larger version. Credit: PHL @ UPR Arecibo, NASA, NERC Satellite Receiving Station, Dundee University, Scotland.
Here are the final results.