The OSIRIS-REX probe spacecraft almost sank into the Asteroid Bennu! It thereby, revealed a hidden secret about the asteroid.
NASA launched its OSIRIS-REX mission back in 2020 in which it sent a probe to asteroid Bennu with an aim to secure at least 60 grams of surface material and bring it back to Earth in 2023. Well, it actually took the probe just18 minutes to send back the first images from the OSIRIS-REX’s sampling maneuver to Earth. But, astonishingly, it took more than a year to solve the mystery of what had happened during the brief touch-and-go. A latest researcher study posted in Science and Science Advances described how an unexpected outburst of dust and rock on the asteroid almost caused the probe to sink into it.
In the initial stage, planetary scientists expected to find the surface of asteroid Bennu mostly dusty. Instead, the probe landing on the asteroid found it to be totally different! Researchers have traced the progress of the probe on asteroid Bennu, which revealed that the probe landed on a rubble pile, instead of the expected rocky surface. The report says if the probe hadn’t been programmed to lift itself back into its orbit after the landing within a few seconds, then this asteroid would have trapped and ingested it!
This is because of the loosely bound surface of the asteroid. “The asteroid is so loosely bound that the brief jet of gas that was supposed to blow surface material into the collection hopper instead blasted out 6,000 kilograms (13,000 pounds) of dust and rock,” OSIRIS-Rex team member Cat Wolner mentioned. Because of its weird surface structure, NASA compared it to a pit of plastic balls. Also, it showed that there is no cohesion or other force that holds the outer layers of Bennu in place except the asteroid’s feeble gravity.
The OSIRIS-REX team had earlier selected a 20-meter-wide crater as the best landing target to take a sample from during the mission. The plan of the probe was simply to touch the surface and stay there for five seconds with its Touch and Go Sample Acquisition Mechanism (TAGSAM). However, when TAGSAM touched the surface, it didn’t stop and it submerged almost half-a-meter before the spacecraft reversed course and rose up into the air.
It was this accident that revealed to the scientists this amazing secret of Asteroid Bennu.