Unveiling the Astonishing Nature of Asteroid Bennu: Surprising Discoveries by Researchers
 |
| The Unexpected Encounter: Bennu's Surprise Encounter with NASA's OSIRIS-REx spacecraft, a Near Miss |
When the OSIRIS-REx probe reached the asteroid Bennu, it encountered a celestial body that defied scientists' expectations in both appearance and behavior.
In the early stages of planning NASA's initial asteroid sample collection mission, there was great excitement within the space science community due to Japan's Hayabusa mission. In 2010, Hayabusa made history by successfully delivering a fragment of the asteroid Itokawa to Earth, providing a glimpse of the space rock's surface. Prior to that, Hayabusa had extensively mapped Itokawa, revealing a landscape featuring boulders along with smooth, beach-like plains covered in gravel and sand.
These images of Itokawa heavily influenced the design of NASA's OSIRIS-REx mission. However, upon reaching Bennu, the OSIRIS-REx team was confronted with a stark reality: the asteroid was vastly different from their expectations.
Kevin Walsh, a planetary scientist and the lead scientist of the Regolith Development Working Group of the OSIRIS-REx mission, explained, “The strategy for planning with OSIRIS-REx was to take Itokawa and all of the observations of asteroid Bennu that we had made of it before. So we would look at the different way [the two asteroids] reflect light and the different way they reflected radar, and every indication was that Bennu would have more ponds of fine grains than Itokawa."
However, this assumption proved entirely incorrect. Upon arrival at Bennu, the spacecraft's cameras unveiled a landscape more akin to a rocky, uneven terrain, devoid of the smooth, open areas that were envisioned for the OSIRIS-REx sample collection.
Dante Lauretta, the mission's chief scientist, expressed concerns that the sample collection might be impossible due to these unforeseen circumstances. The spacecraft's landing design had initially targeted an accuracy of about 164 feet, as Bennu's surface properties appeared consistent with a smooth area. The unexpected rocky terrain presented a significant challenge.
Amidst this predicament, an unexpected source of support emerged in the form of Sir Brian May, the renowned guitarist of the rock band Queen and an astronomy enthusiast. May, who holds a PhD in astronomy, offered his expertise in stereoscopic imaging to the OSIRIS-REx team. Despite the spacecraft lacking a stereo camera, May skillfully selected and processed images from various angles to create 3D views of Bennu's surface. This helped the team identify a suitable, obstacle-free crater for the sample collection.
With May's assistance, the team pinpointed a suitable location within the narrower confines of the Nightingale Crater, measuring just 33 feet in width, instead of the originally planned 164 feet. They had to reprogram the spacecraft accordingly.
The descent to Bennu was executed smoothly, but an unexpected twist occurred during the sample collection. Contrary to expectations, the surface behaved like a swamp, causing the spacecraft to sink 19 inches into Bennu. As the sample collection proceeded and the spacecraft's thrusters fired to back away, a significant amount of debris spewed from the crater, engulfing the ascending spacecraft.
The OSIRIS-REx team learned of this incident only when onboard camera images reached Earth, raising concerns that the stirred-up gravel could have damaged the spacecraft during its retreat.
Despite these operational challenges, the OSIRIS-REx mission managed to collect a more substantial amount of asteroid material than originally planned. The spacecraft is scheduled to return this cargo to Earth on September 24, and Dante Lauretta anticipates releasing initial scientific findings from the sample analysis later this year.
Bennu's surprises have not ceased, leaving researchers eager to uncover more about this intriguing asteroid.
إرسال تعليق