posted January 30, 2014
Last fall the Aerospace Picosat Team invited Aerospace employees to suggest places on Earth to photograph from space, using the picosatellite AeroCube-4C. These are the results.
Kaye Shelnutt and Joanne English asked for a picture of the coast of Israel. The result might well be the most spectacular photograph of the Mideast ever taken from an unclassified satellite. The single picture shot by a camera aboard the AeroCube-4C displays the setting for 5,000 years of recorded history from Egypt to Turkey. Easily identifiable land and water is visible that includes part of Egypt and all of the Suez Canal, the Gulf of Aqaba, the Dead Sea, the historic River Jordan, the Sea of Galilee, all of Israel, all of Lebanon, and large parts of Jordan, Syria, Cyprus, and Turkey, as well as the Mediterranean Sea and a portion of Saudi Arabia.
Generally speaking, requests to photograph large land and water masses juxtaposed against each other turned out reasonably well, while requests for land locations without identifying large landmarks produced undifferentiated images.
Dr. George Paulikas, a former Aerospace executive vice president for whom the Paulikas Mall on the Aerospace campus is named, understood this limitation when he submitted a request for a specific longitude and latitude that he identified as his birthplace. The photograph shows an easily recognizable body of water that looks like a fat worm from orbit and is the Kaunas reservoir in Lithuania.
Paulikas could see the river Nemunas leading out of the reservoir and where it passed the small town of Smalininkai. That’s where, he noted, at the age of 8 he used to paddle around on logs, much to the horror of his mother. He was actually born about 25 miles to the west in the town of Pagegiai, but said he “gave the coordinates of Smalininkai thinking it would be more recognizable being right on the river.”
And he was definitely correct. Photo requests for the San Francisco Bay area, the coast of Los Angeles, and islands such as New Zealand, Hawaii, Puerto Rico, and Jamaica, all came out recognizable.
On the other hand, large buildings such as Michigan Stadium, the largest football stadium in the world, with a seating capacity of 109,901, were too small to photograph, even with the satellite’s narrowest-focus lens. The same for Lambeau Field, Ohio Stadium, the Eiffel Tower, and other structures requested.
The very first request that came in was for an image of Mt. Everest. The resulting photo of the Himalaya Mountains and Tibet became one of the favorites among the Picosat Team. The image shows the snow-covered peaks in sharp detail along with a clear view of Tibet. At the same time, the view of the lower elevations in the Ganges River Valley is partially obscured by the haze. Mt. Everest itself is in the lower center of the photo, among the snow-covered peaks slightly to the right and below the bowtie-shaped lake.
The idea behind the Picosat Team’s offer to take photos on request was to enlist the general Aerospace population for help with testing the capability of the AeroCube- 4C in gathering photographic data from diverse specific locations.
In that sense, the test was a rousing success, as the team refined certain operational procedures and gained a better understanding of the issues involved in targeting multiple specific locations.
Weather turned out to be a big issue in getting usable photographs. The team made many attempts to take photographs of Ireland and other locations in northern Europe, but there were always enough clouds to obscure the view. Then, due to the orbit of the satellite and the time of year, it was night when the AeroCube was over that part of the world during most of December and part of January.
AeroCube-4C is a 1U CubeSat (10 x 10 x 10 cm in dimension) that contains various “first of a kind” mission technologies including solar panel wings that close and open to tune the ballistic coefficient and enable efficient formation flying; three-axis attitude control to better than 3 degrees absolute accuracy; a 0.3-square-meter deployable deorbit device; sub-miniature reaction wheels; and a launch environment data logger that records ascent accelerations, pressure, and temperature.
AeroCube-4C contains three cameras equipped respectively with wide angle, medium, and narrow-focus lenses. The cameras are two-megapixel cell-phone cameras acquired commercially. The narrow-focus lens (22 degrees) will photograph an area approximately 135 by 180 kilometers. The medium focus lens (57 degrees) will photograph an area approximately 500 by 700 kilometers. The wide-angle lens is a fisheye with a 185-degree field of view, and can see the horizon in all directions when nadir pointing. From a nominal satellite altitude of 600 km, the region of the Earth seen by the fisheye lens is about 5800 km wide.
Rich Welle, picosat program manager, noted that the cameras on AeroCube-4C were installed primarily for verifying the attitude-control system of the satellite and that Earth observation was originally conceived as a secondary mission. However, because the AeroCube-4C images were so compelling, AeroCube-7 will now be equipped with an upgraded imaging system that should provide higher resolution Earth photos with possible scientific and/or commercial uses.
You are welcome to download any of the pictures and post to your personal websites, email to friends, or use in printed material. For any use, please put in a conspicuous location near the picture “AeroCube-4 photo © The Aerospace Corporation.”