Located near Bennu’s equator, site Osprey is set in a small crater with a 33 ft (10 m) radius. Various areas within the crater are being evaluated for sample collection–one east of the crater’s center and one west of the crater’s center. These sampling areas have a 16 ft (5 m) radius. Given Osprey’s geographical position on Bennu’s equatorial bulge, it is possible that the region contains material from both the northern and southern hemispheres. The diversity of rock types in Osprey’s surrounding area suggests that the regolith within Osprey may also be diverse. Osprey has the strongest spectral signature for carbon-rich material among the four sites. It also ranks second for the highest albedo and color variation among the candidate sites. A large, dark (low albedo) patch of material in the center of the site is of high scientific interest for the mission team.
This set of stereoscopic images provides a 3D view of site Osprey, located in Bennu’s southern hemisphere. The two images in this stereo pair were taken from slightly different viewpoints, with one of the images meant for the left eye and the other for the right. The two images are then combined by the brain to give the perception of depth. To see the pair in 3D, print off this image and view it through a stereoscope. The cropped and processed images were obtained on April 4, 2019, by the PolyCam camera during Flyby 5A of the mission’s Detailed Survey: Baseball Diamond phase.
This anaglyph of site Osprey was made from the stereopairs seen above. Each stereoscopic image was encoded using filters of chromatically opposite colors—one made with red and the other with cyan. When viewed through color-coded anaglyph glasses, each of the two images reaches the eye it’s intended for, and a 3D image is produced. Anaglyphs are helpful for selecting a sample collection site because they allow the team to intuitively understand the three-dimensional structure of things like boulders and craters.
These Boulder Maps for site Osprey detail the number and location of boulders present within the region. Because Osprey has several possible sampling regions, a boulder count map was produced for each of these regions. The boulders are counted by the human eye, using a single image at a time. Many of these boulder counts were made by members of the public who participated in the CosmoQuest Bennu Mappers citizen science campaign. The boulder counter marks each boulder by the longest axis (point to point) in order to calculate maximum boulder size. Rocks that are 10-21 cm are marked in yellow. Anything larger than 21 cm is marked in red. Rocks and debris that are ingested by the spacecraft’s Touch-and-Go Sample Mechanism (TAGSAM) head must be no more than 2.5 cm wide.
Sample Site Location