National Aeronautics and Space Administration’s (NASA) asteroid-sampling probe, OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) spacecraft passed by the asteroid Bennu for the last time this month ending its two-and-a-half-year stay at the space rock. In a press release on Wednesday, NASA said that OSIRIS-REx completed its last flyover of Bennu around 6 am EDT (3:30 pm IST) on April 7 and is now slowly moving away from the asteroid. However, the mission team will be waiting a few more days to see how the spacecraft changed the surface of Bennu when it grabbed a sample of the asteroid.
With the help of this flyby, the team would document surface changes resulting from the Touch and Go (TAG) sample collection manoeuvre that took place on October 20, 2020. Dr Dante Lauretta, principal investigator for OSIRIS-REx at the University of Arizona said in a statement that by surveying the distribution of the excavated material around the TAG site, the research team will learn more about the nature of the surface and subsurface materials along with the mechanical properties of the asteroid.
The data collected by the spacecraft will also take time to reach the earth where scientists will download it.
Mike Moreau, deputy project manager of OSIRIS-REx at NASA’s Goddard Space Flight Center in Greenbelt, Maryland said that they collected about 4,000 megabytes of data during the flyby in October. OSIRIS-REx imaged Bennu for 5.9 hours that covered more than a full rotation of the asteroid. It then flew within 2.1 miles of distance to the surface of Bennu.
The asteroid is approximately 185 million miles from Earth which means the team on earth can only achieve a downlink data-rate of 412 kilobits per second, mentioned the NASA statement. Hence, it will take several days for the team to download the entire flyby data.
OSIRIS-REx will remain floating near Bennu until May 10 after which it will begin its two-year journey back to the earth. The mission will finally deliver the asteroid sample to Earth on September 24, 2023.