It's been seven years since the launch of NASA's OSIRIS-REx mission to collect and return samples of asteroid Bennu, and the long wait for the spacecraft's homecoming is nearly over.
Imagine a spacecraft meticulously designed and guided by the most brilliant minds in astrophysics, embarking on an interstellar quest to touch the essence of an ancient space rock. Now, picture that same spacecraft, after years of relentless pursuit, making a triumphant return to Earth's doorstep, bearing secrets of the cosmos and the hopes of unravelling mysteries that have eluded us for millennia. This remarkable event is real and is set to unfold this weekend.
When will the OSIRIS-REx mission land the asteroid Bennu sample?
This Sunday, 24 September, at 9:42am in the UK (4:42am EDT, 2:42am MDT), the OSIRIS-REx spacecraft will release the asteroid sample container return capsule and approximately five hours later, at around 10:55am EDT (8:55am MDT, 5:55pm in the UK), the capsule will finally land in the western Utah desert.
Over several years, NASA and the OSIRIS-REx mission team have carefully tracked the spacecraft's velocity and trajectory, culminating in precise calculations for its scheduled landing.
How can I watch the OSIRIS-REx mission?
NASA will provide live coverage starting at 10am EDT (8am MDT, 3pm in the UK) on Sunday, 24 September 2023. You can watch the live stream on NASA Television, NASA TV's YouTube channel (see below), the NASA app, and the official NASA website.
Additionally, NASA plans to offer a Spanish-language version of the OSIRIS-REx landing, accessible via the space agency's social media platforms on X (formerly known as Twitter), Facebook, and YouTube.
The live stream will continue until the asteroid sample return capsule reaches the cleanroom facility at the landing site.
NASA has also scheduled a press conference to follow the sample canister's arrival at the temporary cleanroom. This press conference will also be available for streaming on NASA's website at 5pm EDT (3pm MDT, 10pm in the UK).
What is the OSIRIS-REx mission and why is it important?
The OSIRIS-REx mission, which stands for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, is a significant and ambitious endeavour led by NASA.
It was launched 8 September 2016, and arrived at the near-Earth asteroid Bennu on 31 December 2018. On 20 October 2020, it achieved a remarkable feat by safely collecting a sample of at least 2.1 ounces (60 grams) from the asteroid's surface.
The next major milestone is the return of this precious sample to Earth, scheduled for 24 September, 2023. This mission is a historic milestone, being the first US mission to retrieve material from an asteroid.
The importance of OSIRIS-REx lies in its profound scientific goals. The collected sample, when returned, will provide scientists with invaluable insights into the formation of our early solar system and the origins of life itself.
This mission has the potential to unlock critical information about the conditions and materials present during the early stages of the solar system, shedding light on the processes that led to life emerging on Earth.
Additionally, OSIRIS-REx contributes significantly to planetary defence efforts. Studying and characterising asteroids like Bennu will enhance our understanding of near-Earth objects' properties and behaviour. This knowledge is essential for developing strategies to mitigate potential asteroid impacts, safeguarding our planet in the future.
It's worth noting that OSIRIS-REx is the third major planetary science mission under NASA's New Frontiers Program, following the successful missions of New Horizons and Juno.
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Mission Timeline
OSIRIS-REx is a seven-year mission that launched in 2016. Sunday is an exciting landmark – but not the end.
- 8 Sep, 2016: OSIRIS-REx was launched into space
- 3 Dec, 2018: OSIRIS-REx arrived at asteroid Bennu.
- 20 Oct, 2020: OSIRIS-REx successfully collected a sample from Bennu.
- 10 May, 2021: OSIRIS-REx started its journey back to Earth.
- 24 Sep, 2023: OSIRIS-REx expected delivery of the sample capsule to Earth.
- 2029: Extended mission to asteroid Apophis will begin
What is Asteroid Bennu?
Bennu, an asteroid first identified by the Lincoln Near-Earth Asteroid Research (LINEAR) survey on September 11, 1999, belongs to the intriguing category of B-type asteroids. These celestial bodies are characterised by their abundant carbon content and diverse minerals, resulting in an astonishingly low surface reflectivity. Bennu, in particular, absorbs most of the sunlight that bathes it, reflecting a mere four per cent.
This enigmatic space rock serves as a cosmic time capsule, preserving the origins of our solar system, with its formation dating back over 4.5 billion years. Bennu's ancient nature offers a rare opportunity for scientists to delve into the distant past, potentially harbouring molecules and materials that existed during the emergence of life on our home planet, Earth.
Structurally, Bennu falls into the category of "rubble-pile" asteroids, a term that may sound less flattering but holds profound significance in astronomy. It is a conglomerate of countless rocky fragments drawn together by the relentless force of gravity. The prevailing theory suggests that it originated from the remnants of a colossal parent asteroid, shattered by a cataclysmic cosmic collision.
Furthermore, Bennu presents a window into the past and a tantalising glimpse of a potentially resource-rich future. Hidden within its rocky core lie traces of precious metals such as platinum and gold, which hold the promise of fueling future deep-space exploration endeavours. Water, a vital resource in the cosmos, is also believed to reside within Bennu's confines, essential for sustaining life and facilitating interstellar travel.
Yet, the most captivating aspect of Bennu lies in the small but existent possibility that it could alter the course of Earth's history in the coming century. While the odds are slim, vigilant scientists meticulously monitor Bennu's trajectory to ensure our planet's safety.
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Why was Bennu chosen for the OSIRIS-REx sampling mission?
Asteroid Bennu was carefully chosen as the primary target for NASA's OSIRIS-REx mission in 2008 based on several critical factors. Among the numerous near-Earth asteroids known at the time, Bennu stood out for its suitability.
It was selected because its orbit around the Sun closely resembles that of Earth, falling within the range of 0.8 to 1.6 Astronomical Units (AU) (equivalent to 19.68 million kilometres to 239.36 million kilometres.). Moreover, Bennu's relatively slow rotation was crucial in ensuring a safe environment for the spacecraft to collect a sample. To meet this safety requirement, the asteroid needed to have a diameter exceeding 656 feet (200 meters).
In addition to these considerations, scientists were particularly interested in studying a specific type of asteroid: those rich in carbon and relatively unaltered since the early stages of the solar system's formation. Bennu was among a select group of only five asteroids known at that time that fulfilled all of these essential criteria, making it the optimal choice as the destination for the OSIRIS-REx mission.
What is the size of Asteroid Bennu?
Asteroid Bennu's average diameter of just over 490 meters might seem very small compared to the vast expanse of planets. In perspective, Bennu is only a tad wider than the Empire State Building's height. On the other hand, it's pretty heavy, weighing around 78 billion kilos.
However, NASA suggests that this asteroid likely fractured away from a far more colossal celestial body a staggering 2 billion years ago.
What will happen during the OSIRIS-REx sample landing on Sunday?
If everything goes according to plan, the spacecraft is set to release the sample capsule from OSIRIS-REx when it's approximately 63,000 miles (102,000 kilometres) away from Earth early on Sunday. Since leaving Bennu, the spacecraft has executed various manoeuvres and used its thrusters to ensure that it arrives at Earth at the precise moment for the capsule's release.
The landing area for the capsule is expected to be within a zone measuring approximately 36 miles by 8.5 miles (58 kilometres by 14 kilometres) located on the Defense Department's Utah Test and Training Range.
Parachutes will be deployed to gradually slow down the capsule to a gentle speed of 11 miles per hour (17.7 kilometres per hour) to ensure a safe landing.
- 6:42am EDT (4:42am MDT, 9:40am UK time): OSIRIS-REx releases the sample container return capsule.
- 7:02am EDT (5:02am MDT, 12:02 UK time): OSIRIS-REx changes course away from Earth and toward asteroid Apophis.
- 10:42am EDT (8:42am MDT, 3:42pm UK time): Capsule enters Earth's atmosphere at an altitude of 82 miles (132 kilometres), travelling at 27,650 mph (44,498 kph).
- 10:43am EDT (8:43am MDT, 3:43pm UK time): Capsule experiences highest temperatures reaching 5,000 degrees Fahrenheit (2,760 degrees Celsius).
- 10:44am EDT (8:44am MDT, 3:44pm UK time): Drogue parachute deploys at 102,300 feet (31,181 meters) altitude.
- 10:45am EDT (8:45am MDT, 3:45pm UK time): OSIRIS-REx makes its closest approach to Earth, passing just 484 miles (779 kilometres) away.
- 10:50am EDT (8:50am MDT, 3:50pm UK time): Main parachute deploys at 5,050 feet (1,539 meters) in altitude.
- 10:55am EDT (8:55am MDT, 3:55pm UK time): Landing of the return capsule on Earth, carrying Bennu's material.
What will happen after the landing?
After its successful landing and secure packing, the sample container is set to be transported by helicopter to a temporary clean room. Here, a specialised team will meticulously prepare the sample container for its journey to NASA's Johnson Space Center located in Houston.
Over the next two years, scientists will conduct extensive analyses of the rocks and soil contained within the sample, utilising a dedicated cleanroom at the Johnson Space Center.
This invaluable sample will also be distributed to laboratories worldwide, including those operated by OSIRIS-REx mission partners like the Canadian Space Agency and the Japanese Aerospace Exploration Agency.
Remarkably, approximately 70 per cent of the sample will be carefully preserved for future generations equipped with more advanced technology, enabling even deeper insights than what is presently achievable.
This precious sample promises to unveil critical information regarding the formation and history of our solar system, shedding light on the pivotal role asteroids played in the development of habitable planets like Earth. Scientists hypothesise that carbonaceous asteroids like Bennu may have collided with Earth during its early formation, delivering vital elements like water. Therefore, they hope this piece of space rock provides insight into questions such as 'How did the Earth form?' and 'Where did the oceans get their water?'.
However, The main OSIRIS-REx spacecraft will keep flying after its return capsule comes down to Earth, continuing its mission to further our understanding of the cosmos.
What's next for Nasa?
NASA has scheduled a news conference to reveal findings from the OSIRIS-REx asteroid sample, set to take place on October 11.
Meanwhile, as investigations into the Bennu sample continue here on Earth, the spacecraft is embarking on a new mission known as the Osiris-Apophis Explorer (Osiris-Apex). This mission will see the spacecraft journey towards an encounter with the asteroid Apophis in 2029.
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