NASA's space vessel OSIRIS-REx found material that stretches out of the Bennou asteroid in this photo taken on January 19th. This view combines two images, one of which is made in brief exposure to allow Bennu's surface, and another longer exposure, revealing bright star points, the material is emitted by the asteroid. The first months of the NASA OSIRIS-REx asteroid Benuno revealed great surprises, scientists said on Tuesday, including particles of particles emanating from the asteroid, sometimes with the speed of the rocks getting out of Bennu's weak gravitational pore and escaping space.
Mission scientists have said that OSIRIS-REx has detected particle jets at least 11 times since January 6, and experts are unsure what is causing material to be ejected from Bennu's surface.
Dante Lauretta, NASA-funded research scientist at $ 1 billion, origin, spectral interpretation, Resource Identification Security, Regolith Explorer Mission at the University of Arizona, said the discovery of rocks and pebbles particles make Bennu an "asteroid active ", A rare class of small solar objects with a population of only a dozen people of which no one is
Some of the debris thrown out of Bennu returns to the surface of the asteroid. The OSIRIS-REX camera has been observing particles traveling at higher speeds entering orbit around the asteroid while some materials are moving fast enough to escape from Bennu forever, Lauretha said.  Bennu has a width of 492 meters and is shaped like a top. Rid around the equator of Bennu is one of the most striking features of the asteroid along with numerous stones, some of which are large as a multi-storey office building. The asteroid is located on an oval trail that takes it directly into the Earth's orbit at its closest point to the sun, and Ben-Junie is likely to affect Earth at the end of the 22nd century.
OSIRIS-REx discovered the first track at the beginning of January, scientists sent spacecraft commands to make a more systematic search for particle streams. Three of the 11 events found by the end of February were significant, with tens to more than one hundred particles being discarded, according to Lauretta.
Scientists find more streams as they improve their ability to retrieve weak signals from reflected sunlight from
Lauretta said the discovery of the Channel in Bennu is one of the greatest surprises in his scientific career.
The rocks and stones seen to fly from Bennu range from about a centimeter to ten centimeters in size, approximately the size of M & M to a laptop, at speeds up to several miles per hour, according to Lauretta. Some of these slowly moving particles have been observed over periods of at least a week, and appear to be enclosed in the asteroid's gravitational field and end in orbit around Bennu, "he said. "So it creates its own set of natural satellites, and then some of them are noticed to return to the surface." In general, it seems that Bennu has a continuous population of particles that float on it from discrete ejection events. Laureth asked. – It's incredibly exciting. We do not know the mechanism that causes it right now. In fact, we are still learning how to process data, analyze information, and understand what's happening on this asteroid. "
One of the theories dealt with by Osiris-Rex's team is that the bursts of the channel can be linked to Bennu's position in his orbit around the Sun. The asteroid reached the perihelion, its closest point to the sun in its 1.2-year orbit, early January, a few days after OSIRIS-REx discovered the first particle track.
The comets are under the most intense solar heating until they reach the perihelion, warming the volatile ice material and triggering eruptions that create an obscure coma around the comet's core.
"There is speculation that this may be a close approach, but we have not yet confirmed this," said Lauret. OSRIS-REx has not noticed any eruptions since the end of February, but the spacecraft has left its orbit around Bennou and flies a long distance from the asteroid, which could exclude such observations.
NASA's OSIRIS-REx NAVAR cameras capture this photo of the Bennou asteroid on January 17 at a distance of about 1 mile (1.6 km). The large stone in partial shade in the lower right corner of the frame is about 50 meters away. Author: NASA / Goddard / University of Arizona / Lockheed Martin
Navigators planning the OCHRIS-Rex trajectory around Bennu have determined that jets of particles do not pose a threat to the spacecraft that has entered the orbit around the asteroid. the smallest planetary body ever circulating from a spacecraft, and OSIRIS-REx flew with a series of slow speeds ranging between 1 mile and 1.3 miles (1.6 km to 2.1 km) from the asteroid.
Bennu's gravitational field is about 100,000 times less. from the Earth so weak that airborne flight specialists have to take into account other forces, such as solar radiation, acting on the spacecraft as it travels around the asteroid.
Designed to take a sample of Bennou to return to Earth, OSIRIS-REx was launched from Cape Canaveral in September 2016 and arrived in the vicinity of Bennu at the end of last year. After the encounter with Bennu, spacecraft tools discovered clay minerals, hydroxyl and magnetite on the surface of the asteroid. The findings show that the material on Bennu's surface was once in contact with the water. Bennu's interior looks porous, and the evidence suggests that Bennu is an asteroid with a "pile of piles" formed by piles of rock gravitationally connected to each other. Measurements from OSIRIS-REx indicate that Bennu has a bulk density similar to that of coal. 19659003] Bennu revolves once every 4.3 hours and the speed of rotation accelerates, scientists said.
OSIRIS-REx has directly detected the change in Bennu spin speed caused by uneven heating and cooling of the surface of the asteroid when rotated. Within 1.5 million years, Bennu is expected to revolve twice its current value, Lauretta said. Benward's crossed-out topography forced staff to re-plan the collection of samples, Lauretta said Bennu was a "non-ideal" target for OSIRIS-REx, rich in minerals, who will tell the researchers about the history of the solar system. Asteroids and comets routinely affected the Earth shortly after the formation of the planet more than 4.5 billion years ago, carrying water and organic molecules, building blocks of life.
"As a scientist interested in returning this material to our laboratories here on Earth, this is really exciting because it means we will have a wide range of materials to study from the dawn of the solar system to find out the processes of forming the planet, and even why Earth is a habitable planet, abundant oceans and the origin of life, "Lauret said.
But many stones are dotted on the surface of Bennu. The OSIRIS-REx ground crew has counted more than 200 stones measuring at least 10 meters – 33 feet, much more than predicted by scientists based on ground-based radar data for the asteroid.
The rough surface "can create some challenges for our navigation systems that rely on LIDAR tools that are surface-reflecting lasers to give us our range for the asteroid as well as imaging technologies that guide us to the potential sample site, "said Lauretta.
This image shows a view of the southern hemisphere of the Bennu asteroid and in space, and shows the number and distribution of stones on Bennu's surface. The image was received on March 7 from NASA OSIRIS-REx SpaceCat PolyCam Camera from a distance of about 5 km. The large, bright stone just below the center of the image is 7.4 meters wide, which is approximately half the width of the basketball court. Credit: NASA / Goddard / Arizona University
OSIRIS-REx will take a sample of Bennu's surface using a device known as TAGSAM or a touch-and-pass acquisition mechanism. Formed as a vehicle's air filter, TAGSAM is mounted at the end of a robotic hand that will shortly connect to the surface of the asteroid, release a bottle of compressed nitrogen gas to wash pieces of dust and rock, then climb from Benna.
TAGSAM will capture the samples blown out of the nitrogen pulse and suck them into a collector with a rush of air similar to the way the vacuum cleaner works. Once the scientists are satisfied that they have a good sample, the TAGSAM head will be placed in the OSIRIS-REx return tank for the trip back to Earth.
Engineers initially designed the OSIRIS-REx spacecraft built by Lockheed Martin to direct a sample. collection area about 164 feet (50 meters) in diameter.
"The asteroid is so robust that there will be no areas free of a radius of 25 meters," said Rich Burns, project manager at NADA Space Flight Center in Maryland. – What do I mean at risk? These large stones present hazards, as well as the heavy slopes of the surface and the slopes on the surface of the asteroid. "
Instead, OSIRIS-REx will have to go down to Bennu with much greater precision to hit a smaller bull.
"You can imagine shooting an arrow, just trying to hit the board, now we'll try to hit the center of the bullshit," Burns said.
Sampling maneuver is planned for the middle of 2020, and the landing of the Utah reverse sample is scheduled for September 2023.
Scientists want a fairly smooth place with fine gravel and dust to set up OSIRIS -REx for sampling maneuver. When OSIRIS-REx was designed, employees expected Bennu to have wider sections of appropriate sampling areas than it was.
Some Bennu crash craters seem to contain tanks with relatively smooth terrain and fine grain material. These sites may be the best options for OSIRIS-REx to take a sample, scientists say in presentations at the 50th Lunar and Planetary Science Conference near Houston this week.
The Artist Concept for the OSIRIS-REx Spacecraft. Author: NASA / University of Arizona / Lockheed Martin
Japanese mission Hayabusa 2, which is investigating another asteroid named Ryugu, faced such a challenge once it reached its target last year. Japanese managers have discovered that Ryugu is also covered with rough, rocky material, forcing officials to defer the first landing of Hayabusa 2 from the last year to February.
Restrictions that were initially planned to allow for less space for sampling, stuck between the surrounding stones. The spacecraft successfully collected a sample from Ryugu on February 21 and is expected to return to Earth by the end of 2020.
Lauretta said a contingent from the OSIRIS-REx team would travel to Japan next month to learn from the experience of Hayabusa 2
"We are confident that our systems and our teams are about to put labels in a sampling area with a much smaller area than previously predicted," Burns said.
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