Asteroid Bennu is about to have a friendly visit by NASA’s OSIRIS REx (Origins, Spectral Interpretation, Resource Identification and Security – Regolith Explorer) in October 20th for a sample collection attempt. The first asteroid sample return mission of NASA’s exhibits its survivor spirit by entering the closest-ever orbit around a planetary body to explore it’s surprisingly rough terrain which will prove a challenge for sample collection.
For those who don’t know, asteroid Bennu is the smallest body ever orbited by spacecraft. It has a close approach to Earth every six years and is potentially hazardous as it has an estimated 1‐in‐2,700 chance of impacting the Earth during one of its close approaches in the late 22nd century; one of the reasons why NASA has selected this tiny asteroid for its maiden sample return mission. Osiris Rex was launched on September 18th 2016 from Cape Canaveral, United States. The probe reached the asteroid in December 2018 and is set to return to Earth in September 24th 2023.
The first sample collection rehearsal which is a practice run of all the events leading up to the sample collection was successfully completed last month. The second rehearsal was set for June but due to the constraints posed by the COVID-19 pandemic, it has been postponed to August 11. The touch and go (TAG) sample collection event planned for August 25th has been postponed to October 20th as well.
OSIRIS-REx’s sampling mechanism, TAGSAM (Touch-And-Go Sample Acquisition Mechanism) will collect the sample from the site Nightingale which is located in a crater high in Bennu’s northern hemisphere. During the TAG event, TAGSAM will disturb the surface by firing a charge of pressurized nitrogen which will kick up regolith particles (loose dust and rocks) from the surface. The regolith will be collected by the sampler head at the end of TAGSAM. The mission can be attempted for three times only as its resources would permit. No further attempts will be made if the attempt on October 20th is successful.
– Anu V Nair
References
Further Reading: APRIL 14, “Checkpoint” rehearsal for OSIRIS-REx https://shasthrasnehi.com/april-14-checkpoint-rehearsal-for-osiris-rex/
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