NASA's OSIRIS-REx: Collecting Asteroid Samples for Earth
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Chapter 1: OSIRIS-REx Touches Bennu
In a groundbreaking mission, OSIRIS-REx successfully made contact with the surface of the asteroid Bennu to collect samples. On October 20, the spacecraft executed a touch-and-go (TAG) maneuver, gathering material from Bennu's surface before retreating into space. This event marked a historic achievement as OSIRIS-REx became the first NASA spacecraft to retrieve a sample from an asteroid.
A direct quote from NASA highlights the precision of the maneuver.
At precisely 1:50 p.m. EDT, OSIRIS-REx activated its thrusters to break free from its orbit around Bennu. The spacecraft extended its 11-foot sampling arm, known as the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), and descended approximately half a mile (805 meters) to reach the designated collection site, named Nightingale. The spacecraft made contact with the asteroid for 4.7 seconds, and initial data suggests that the sample collection was successful, though it will take about a week for scientists to quantify the gathered material.
Bennu, located over 322 million kilometers (200 million miles) from Earth, is considered an ancient remnant from the early Solar System. Researchers believe that Bennu may be similar to the primordial materials that formed our planets and potentially contributed to the origins of life on Earth.
Section 1.1: The Challenges of Landing
Upon OSIRIS-REx's arrival at Bennu, astronomers discovered the asteroid's surface was strewn with large boulders, complicating the identification of a suitable landing site. The rocks on Bennu are comparatively fragile, crumbling more easily than those found on Earth. After extensive analysis, mission planners concluded that the safest landing zone was Nightingale, a relatively clear area roughly the size of a small parking lot.
Subsection 1.1.1: The Significance of Bennu
Bennu is thought to be a crucial piece of evidence from the Solar System's formative years. Its water-rich composition could provide insights into whether such bodies delivered water to Earth, contributing to the formation of our oceans. Notably, carbonate minerals, which often appear as streaks on meteorites, can be found on Bennu, indicating its rich geological history.
The first video titled "OSIRIS-REx: NASA's First Mission to Deliver Asteroid Samples to Earth" delves into the journey of the OSIRIS-REx mission, showcasing its goals and achievements.
Section 1.2: Implications for Life
“If DNA's building blocks were formed early in the solar system and preserved in carbon-rich asteroids, they could have reached Earth and other celestial bodies, suggesting that the foundations of life were not exclusive to our planet,” explains Dante Lauretta, the principal investigator of OSIRIS-REx.
Chapter 2: The Journey and Technique
Launched on September 8, 2016, OSIRIS-REx reached Bennu on December 3, 2018. After a month of orbital operations, the spacecraft began scouting for potential landing sites from September 4 to 27. To ensure a safe touchdown, the spacecraft matched the asteroid's rotation before executing a critical glide past a massive rock formation dubbed Mount Doom.
The second video, "OSIRIS-REx Sample Collection at Asteroid Bennu: SamCam View of TAGSAM," provides a detailed look at the sample collection process during the mission.
Upon making contact, the spacecraft released a burst of high-pressure inert gas, which dislodged debris from Bennu's surface for collection by TAGSAM. This TAG maneuver was performed autonomously, following pre-programmed instructions.
If successful in gathering a minimum of 60 grams (about two ounces) of material, the sample will be secured within a Sample Return Capsule (SRC) in preparation for its journey back to Earth. OSIRIS-REx plans to leave Bennu's orbit in March 2021, with the sample expected to land in Utah's desert on September 23, 2023. Should the initial attempt fall short, a backup collection attempt is scheduled for January 12, 2021, in a more boulder-free region known as Osprey.
“This historic achievement by NASA illustrates the extraordinary collaboration of teams across the nation, overcoming significant challenges to broaden our understanding of the cosmos,” stated NASA Administrator Jim Bridenstine.
Even before the final assessment of the sample's mass, several remote sensing techniques can offer insights into the success of the collection. Analyzing before-and-after images of the touchdown site will reveal any disturbances caused by the maneuver, indicating the volume of material collected.
“Sooner or later, we will face a catastrophic threat from space. Of all the possible threats, only a gigantic asteroid hit can destroy the entire planet. If we prepare now, we better our odds of survival. The dinosaurs never knew what hit them,” warns physicist Michio Kaku.
NASA will also leverage the SamCam camera to document the TAGSAM head's condition, potentially revealing how much material remains after the collection. If conditions permit, there may even be images of the sample itself within the instrument.
Another method for estimating the sample's mass involves extending the TAGSAM arm and spinning the spacecraft. By measuring the rotational speed under a specific force, researchers can determine the mass contained in the chamber.
The OSIRIS-REx mission promises to enhance our understanding of Bennu, asteroids, and the broader Solar System significantly. In 2135, Bennu is expected to pass between the Earth and the Moon, presenting a one in 2,700 chance of colliding with our planet in 2186.
James Maynard is the founder and publisher of The Cosmic Companion. He resides in Tucson with his wife, Nicole, and their cat, Max.
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