The proposed landing sites for asteroids are now four in number.



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The proposed landing sites for asteroids are now four in number.

Here is the video produced by NASA showing the entire asteroid and the location of the landing sites. You can watch the video right here.

Legend: In the photo, the four sample collection sites on the asteroid Bennu selected by the Origins mission, Spectral Interpretation, Resource Identification, Security-Regolith Explorer or OSIRIS-REx from NASA. Nightingale Site, top left, is located in the northern hemisphere of Bennu. The Kingfisher sites, on the upper right, and Osprey, on the lower left, are located in the equatorial region of Bennu. The Sandpiper site, lower right, is located in the southern hemisphere of Bennu. In December, one of these sites will be chosen for the landing of the mission. Credits: NASA / University of Arizona

After months of struggling with the harsh reality of the surface of the asteroid Bennu, the team responsible for NASA's first asteroid return mission has selected four potential sites for the OSIRIS- REx to "mark" his cosmic dance partner.

Since arriving in December 2018, the OSIRIS-REx spacecraft has mapped the entire asteroid in order to identify the safest and most accessible points for taking a sample. These four sites will now be studied in more detail in order to select the last two sites – a main and a backup – in December.

The team originally planned to select the last two sites at this stage of the mission. Initial analysis of terrestrial observations suggested that the surface of the asteroid would likely contain large "ponds" of fine-grained material. The first images of the spacecraft, however, revealed that Bennu's terrain was particularly rocky. Since then, the topography filled with blocks of asteroids has created a challenge for the team: to identify safe areas containing samplable materials, which must have a diameter of less than 1 inch, to be sufficiently fine for the mechanism to sampling of the spacecraft may ingest them.

"We knew Bennu was going to surprise us and so we were prepared for everything we could find," said Dante Lauretta, OSIRIS-REx's senior investigator at the University of Arizona, at the University of Arizona. Tucson. "As in any exploration mission, dealing with the unknown requires flexibility, resources, and ingenuity. The OSIRIS-REx team demonstrated these essential characteristics to overcome the unexpected during the meeting with Bennu. "

The initial mission schedule intentionally provided for over 300 additional days during the asteroid operation to deal with such unexpected challenges. To demonstrate its flexibility and ingenuity in response to Bennu's surprises, the mission team is adapting its site selection process.

Instead of limiting the choice to the last two sites this summer, the mission will spend four additional months studying in detail the four candidate sites, with particular emphasis on high-resolution observation of each site in order to Identify regions of fine grain. material that can be sampled.

The block maps that Citizen Science Meters helped to create through observations earlier this year were used as one of the many data considered when assessing the security of each site. The data collected will be essential for selecting the last two sites best suited to sample collection.

In order to better adapt to Bennu's robustness, the OSIRIS-REx team made further adjustments to its site identification process. The original mission plan provided an example of a site with an 82-foot radius. The sites without blocks of this size do not exist on Bennu, so the team has instead identified sites whose radius is between 16 and 33 feet. In order for the spacecraft to accurately target a smaller site, the team re-evaluated the spacecraft's operational capabilities to optimize its performance.

The mission has also tightened its navigation requirements to guide the spacecraft to the surface of the asteroid and has developed a new sampling technique called "Bullseye TAG", which uses images of the surface of the asteroid to navigate to the actual surface with great precision. The results achieved so far by the mission have shown that the new standards are commensurate with its capabilities.

"Although OSIRIS-REx was designed to collect a sample of an asteroid with a beach, the outstanding performance in flight to date demonstrates that we will be able to meet the challenge of Bennu's rugged surface," he said. said Rich Burns, OSIRIS-REx Project Manager at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "This extraordinary performance encompasses not only the spaceship and its instruments, but also the team that continues to meet all the challenges that Bennu launches."

The four candidate sampling sites on Bennu are designated Nightingale, Kingfisher, Osprey and Sandpiper – all birds originating in Egypt. The designation theme completes the other two mission conventions: Egyptian deities (the asteroid and the spaceship) and mythological birds (characteristics of the surface on Bennu).

The four sites are diversified by both their geographic location and their geological features. Although the amount of material that can be sampled at each site has not yet been determined, the four sites have been thoroughly evaluated to ensure the safety of the spacecraft when descending, touching and sampling. a sample of the surface of the asteroid.

Nightingale is the northernmost site, located at 56 degrees north latitude on Bennu. There are several possible sampling areas on this site, located in a small crater surrounded by a larger crater 459 feet in diameter. The site contains mainly dark and fine-grained materials and has the lowest albedo or reflection and surface temperature of the four sites.

Kingfisher is located in a small crater near Bennu's equator at 11 degrees north latitude. The crater has a diameter of 26 feet and is surrounded by rocks, although the site itself is free of large rocks.

Kingfisher has the most powerful spectral signature for hydrated minerals.
Osprey is located in a small crater 66 feet in diameter, also located in the equatorial region of Bennu at 11 degrees north latitude. There are several possible sampling areas on the site. The diversity of rock types in the vicinity suggests that the Osprey Regolith could also be diversified.

Osprey has the highest spectral signature of carbon-rich material among the four sites.
The sandpiper is located in the southern hemisphere of Bennu, at 47 degrees south latitude. The site is in a relatively flat area on the wall of a large crater 207 feet in diameter. Hydrated minerals are also present, indicating that Sandpiper may contain a material rich in unmodified water.

During the mission recognition phase, OSIRIS-REx will begin performing detailed analyzes of the four candidate sites. During the first phase of this phase, the spacecraft will cross overhead at each of the four sites, at a distance of 0.8 km, to confirm that they are safe and contain materials that can be sampled. Close-up imaging will also map the features and landmarks needed for autonomous navigation of the spacecraft to the surface of the asteroid. The team will use the data from these passes to select the main sample collection and final backup sites in December.

The second and third reconnaissance stages will begin in early 2020 when the satellite will cross over the two final sites at lower altitudes and will perform surface observations at an even higher resolution to identify features, such as groups of rocks that will be used for surface navigation for the collection of samples. OSIRIS-REx sample collection is scheduled for the second half of 2020 and the space shuttle will return asteroid samples to Earth on September 24, 2023.

New spectacular image of Jupiter

This new image of the Hubble Space Telescope reveals the complex and meticulous beauty of Jupiter's clouds. Taken on June 27, 2019, it features the planet's trademark, Great Red Spot, and a more intense color palette in the clouds that swirl in the turbulent atmosphere of the planet compared to previous years.
Among the most striking features of the image are the rich colors of the clouds that are heading towards the big red spot. This huge anticyclonic storm is about the diameter of the Earth and rotates counter-clockwise between two bands of clouds moving in opposite directions.

As with previous Jupiter images taken by Hubble and other ground-based telescope observations, the new image confirms that the huge storm that has plagued Jupiter's surface for at least 150 years continues to decline. The reason is still unknown, so Hubble will continue to observe Jupiter in the hope that scientists will be able to solve this stormy riddle. Much smaller storms appear on Jupiter in the form of white or brown ovals that can last as little as a few hours or extend over centuries.

The worm-shaped feature located to the south of the large red spot is a cyclone, a vortex turning in the opposite direction to that in which the large red spot rotates. The researchers observed cyclones with a wide variety of appearances on the planet. The two white oval lines are anticyclones, similar to the smaller versions of the Great Red Spot.

The Hubble image also highlights the distinct parallel cloud bands of Jupiter. These bands consist of air flowing in opposite directions at different latitudes. They are created by the differences in thickness and height of the ammonia ice clouds; the lightest bands grow higher and have thicker clouds than the darker ones. The different concentrations are separated by fast winds that can reach speeds of up to 435 mph.

These observations of Jupiter are part of the Outer Planet Atmospheres Legacy program, launched in 2014. This initiative allows Hubble to devote time each year to observing the outer planets and offers scientists access to a collection of maps that helps to understand only the atmospheres of the giant planets of the solar system, but also the atmosphere of our own planet and planets of other planetary systems.

Image credit: NASA, ESA, A. Simon, Goddard Space Flight Center and Mr. H. Wong, University of California, Berkeley.

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