NASA scientists believe that if the possibility of Bennu, an asteroid hitting Earth in a few years is keeping you awake at night you can now rest easier.OSIRIS-REx, the OSIRIS spacecraft of the agency, spent over two years orbiting this space rock. Experts studying possible space rock impacts with Earth were able to get a detailed view of the asteroid.Scientists behind new research are confident that asteroids' total impact probability is only 1 in 1,750. NASA estimates of the cumulative probability that a Bennu impact would occur between 2175-2199 were made before OSIRIS REx was launched to the space rock. They are 1 in 2,700. NASA stated that while it is a higher risk than previous estimates, it still represents a small change to an already minimal risk.Although technically, this is a slight increase in risk, the scientists behind the research don't believe it will have any significant impact. Asteroid trajectory calculations can be improved by the research, which could help reduce concerns about possible impacts from other asteroids.Although the impact probability has increased a little, it is not a significant increase. The impact probability remains pretty stable, according to Davide Farnocchia (lead author), who works at NASA's Center for Near Earth Object Studies, California. He spoke during a news conference on Wednesday, August 11. Overall, I believe that the situation has improved.Precision is importantOSIRIS-REx, also known as Origins Spectral Interpretation and Resource Identification, Security-Regolith Explorer, was launched in September 2016 by OSIRIS-REx. It orbited around the asteroid Bennu on December 2018.The spacecraft spent almost two-and-a-half years studying the space rock orbiting it, hovering above and inspecting every aspect of the rock.The spacecraft's trajectory was amazing. Dante Lauretta (a planetary scientist at Arizona), who is the principal investigator of OSIRIS-REx, and an author on new research, stated during the news conference. We were able go into orbit, and we were also able leave orbit.The spacecraft kept track of its position relative to Earth and the asteroid throughout that period. The new research team was able to refine their understanding of the location and movement of the space rocks for almost two and a quarter years using this data.October 2020 was the culmination of the spacecraft's visit to the asteroid. OSIRIS-REx took a sample from Bennu for its safekeeping. The spacecraft and its valuable cargo left the asteroid in May and returned to Earth. OSIRIS-REx will deposit a sample capsule on September 2023. This delivery will allow scientists to examine asteroid material with all the advanced equipment available in terrestrial laboratories.Scientists don't need to have the sample material in order to study the two-and-a-half years of spacecraft observations. When you add in the work of astronomers observing Bennu on the ground long before OSIRIS/REx existed, scientists now have 20 years worth data about a single space rock.Asteroid trajectories are always uncertain because of the many forces that tug at space rocks as they rattle around the inner solar system. Even though the future Bennus path is now more accurate, this uncertainty persists. However, OSIRIS-REx observations have allowed scientists to significantly reduce their uncertainty.The researchers were able, among other things, to account for tiny orbital changes caused by forces such as radiation from the sun, relativity's impact, and gravity of hundreds more large asteroids that are whizzing around the area.These factors affect all objects in the solar system, but only to a small degree. The team was able to examine the impact of Bennu's two unique characteristics: the plumes that shoot off the asteroid regularly and the rocks interaction that occurs with the spacecraft.Scientists were especially concerned about the Yarkovsky Effect, which is caused by constant temperature fluctuations as regions of an asteroid pass in or out of daylight. This gently pushes the asteroid.Farnocchia stated that the Yarkovsky effect on Bennu is equal to three grapes. This is what drives Bennu's future motion. Because this acceleration is persistent, it builds up over time and becomes extremely significant by the year 2135.It is difficult to predict Bennus' course after 2135, despite scientists' best efforts. Bennu will pass Earth in September that year. It won't be close enough to cause an impact but close enough for Earth's gravity to push the asteroid along its path. Over the next decade and century, Bennus' trajectory will be determined by how precisely this dance unfolds.NASA released a statement regarding the new research, stating that Bennus total impacts probability for 2300 through 2300 is 1 in 1,750. The most alarming date within that time frame is Sept. 24, 2182. Even on that date, Bennus' impact probability is just 1 in 2,700.Beyond BennuScientists are concerned about Bennu, but it is not the only space rock. The planetary defense program aims to identify all asteroids that could potentially have an impact on Earth. NASA reports that scientists have accumulated more than 26,000 near-Earth asteroids to date.Scientists need to be able calculate the trajectory of space rocks so they can accurately identify which asteroids could pose a threat. This trajectory is based on observations of an asteroid's location, however scientists know for years that factors such as the Yarkovsky Effect may affect their calculations.According to researchers, the new OSIRIS-REx data that quantifies the three-grape-heavy Yarkovsky Effect should help scientists understand how this effect affects the trajectory of other asteroids.Farnocchia stated that this was the first time they were able to test their models on an asteroid trajectory at levels never before attempted. These results can be applied to any other asteroid and are extremely accurate.This research was described in a paper published in Icarus on Tuesday, August 10, 2010.Copyright 2021 Space.com. A Future company. All rights reserved. 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