Introduction
Recently, the National Aeronautics and Space Administration (NASA) has successfully brought the sample of potentially hazardous asteroid, Bennu to the Earth. The sample consists of rocky space rubble, collected in space, having a weight of around 100-250 gm. It contains a high level of carbon and water content as per the initial research. This sample is believed to have the earliest fundamental units of life found on Earth. NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer) science team is credited with this discovery, which was carried out as the team’s initial assessment.
OSIRIS-REx is the NASA mission that focuses on providing insight into asteroids, which have the capability of endangering the Earth, along with sharing a glimpse of what lies beyond the Earth. OSIRIS-REx capsule was launched onto the surface of Bennu with the help of the Atlas V411 rocket. The 411 variant has flown five times since 2006 and has successfully launched several satellites and spacecrafts. Two burns by the centaur upper stage achieves escape velocity of 27,000 mph, an hour after lift-off. Learning about the nature of carbon compounds, thus found, is a bigger task to be carried out later. However, the preliminary finding serves as the platform for future endeavours in the study of asteroid samples. The asteroid rubble holds the secrets that will be analysed in the coming decades. These secrets could be the formation of our solar system, the sowing of seeds of life on the Earth, the precautions needed to prevent asteroid collisions with our Earth, etc.
The sample of the asteroid material was put on display at NASA’s Johnson Space Centre (JSC), located in Houston, for the first time since it reached the Earth’s surface last September.
About Bennu
Bennu is a 4.5-billion-year-old asteroid that comes closer to our planet while it is floating around the solar system in space. Thus, it is also called a near-Earth asteroid. It is expected that the asteroid will pass by the Earth in close proximity in the year 2135. This close flyby may change its direction in space, but it is not clear to what extent the impact of this flyby will have on its journey. Probably, Bennu might set out on an unexpected path.
Journey of Bennu
This NASA mission (spacecraft) is an unbelievable scientific feat that is aimed at highlighting the uniqueness of our planet. It is regarded as the first US mission meant for collecting a sample from an asteroid. It collected the sample from Bennu, which is declared as ‘an earth-threatening asteroid’ by NASA. With a chance of 1 in 2,700, Bennu might strike our planet in the year 2182. However, the scientists are more concerned about what the space rock consists of, i.e., probably the building blocks of life.
Having the sample aboard, the OSIRIS-REx capsule plunged back to the Earth at a rapid speed of 43,000 km/hr. The capsule travelled for seven years, covering a distance of 6.4 million km in its round trip across space. On September 24, 2023, it dropped off the Bennu sample in the Utah desert and set out towards another asteroid, namely, Apophis. The capsule is scheduled to reach this asteroid in 2029. Now, it has been renamed as OSIRIS-APEX (OSIRIS-Apophis Explorer).
Utah, also known as the Great Salt Lake Desert, is a large dry lake in northern Utah, the US.
Apophis, discovered in 2004, is a near-Earth object (NEO) and is about 1,100 feet across. It is considered as one of the most hazardous asteroids that could impact the Earth.
From the desert, the sample was taken to JSC, where it was examined by scientists to look for signs of life other than the Earth. It is considered to be the largest asteroid sample containing carbon that has ever reached the Earth’s surface. The scientists will carry out an investigation into this sample to find out if billions of years ago, the asteroids that struck the Earth were responsible for bringing the basic elements for life here.
How the Capsule Collected the Sample
As Bennu has a rocky surface, the capsule searched for a landing site for almost two years. When the capsule came in contact with Bennu, it had to stick the landing and keep the craft from pushing through the asteroid. So, the capsule’s Touch-and-Go Sample Acquisition Mechanism (TAGSAM) shot out a nitrogen blast. Consequently, rocks and dust around the craft started staggering. Some of these rock and dust particles settled in a canister aboard the capsule.
TAGSAM is a robotic arm on the OSIRIS-Rex space probe for collecting a sample from asteroid Bennu.
Later, the capsule’s thrusters shot another blast, and the capsule was raised up from the surface of the asteroid. Next, the capsule did several flybys and left for the Earth in May 2021.
Surplus Sample Material
OSIRIS-REx spacecraft had the objective of collecting merely 60 grams of asteroid rubble. The sample-containing hardware was disassembled carefully by the experts at NASA JSC so that the bulk sample could be revealed. After opening the science canister lid, surplus asteroid material was found lying over the canister lid, base, and the collector head. The process of collecting primary sample got slower due to a lot of surplus material.
Examining Sample Material
Initially, the sample material was considered for ‘quick-look’ analyses by the scientists. For this, they took pictures using infrared measurements, a scanning electron microscope, chemical element analysis, and X-ray diffraction. One of the particles was used to make a 3D computer model with the help of X-ray computed tomography so that its distinct interior could be highlighted. This showed that the sample had plenty of carbon and water content.
Contributors to the Mission
- The Goddard Space Flight Center of NASA did system engineering, overall mission management and safety, and mission assurance.
- The main investigator, Lauretta, headed the science team, and handled data processing and science observation planning of the mission.
- Lockheed Martin Space constructed the spacecraft and managed capsule recovery and flight operations.
- Goddard and KinetX Aerospace managed the navigation of the spacecraft.
- NASA’s JSC processed the sample along with curation for the mission.
The Way Ahead
By studying the material of Bennu, we will get to know the ancient secrets hidden within it. We would get deep insights into how our solar system was formed. The findings of the material containing abundant carbon and clay minerals having water content are just the first small steps, but it took many years of dedicated hard work, collaboration, and progressive technology to complete these initial steps. Further, these findings will enable us to study our celestial surroundings along with the signs of the origin of life and the mysteries of our cosmic past.
The science team of OSIRIS-REx mission would identify the samples and analyse them so that the scientific objectives of the mission could be accomplished. Around three-fourths of the sample will be stored at JSC by NASA to allow, experienced as well as novel scientists around the globe to conduct further research. With the implementation of the mission’s science programme, the properties of Bennu’s sample would be examined by a group of more than 200 scientists from across the world, such as researchers from the Canadian Space Agency (CSA), US institutions, JAXA (Japan Aerospace Exploration Agency), and other scientists from different parts of the world. Several samples would be put on display for the general public at JSC, the Smithsonian Institution, and the University of Arizona.
Expert Comments
According to Bill Nelson, the NASA Administrator, “This is the biggest carbon-rich asteroid sample ever returned to Earth. Carbon and water molecules are exactly the elements we wanted to find. They’re crucial elements in the formation of our own planet, and they’re going to help us determine the origins of elements that could have led to life.”
The samples of Bennu are also displayed at the Smithsonian’s National Museum of Natural History, located in Washington DC. The museum’s curator of meteorites and a part of the OSIRIS REx mission, Tim McCoy said, “Having now returned to Earth without being exposed to our water-rich atmosphere or the life that fills every corner of our planet, the samples of Bennu hold the promise to tell us about the water and organics before life came to form our unique planet.”
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