In 2016, the National Aeronautics and Space Administration (NASA) launched a spacecraft dubbed OSIRIS-REx to answer some of the major questions about the history of our solar system. Four years later, the spacecraft is now finally prepared to implement the long-planned feat of collecting a sample from asteroid Bennu and returning it to Earth for scientific analysis. NASA will broadcast the live coverage on October 21, 2020, at 2:30 am IST.
Why is the mission important?
OSIRIS-REx is NASA’s first attempt at sampling an asteroid and bringing it back to Earth for analysis.
This mission is particularly important as scientists believe that Bennu was part of a much bigger asteroid that blew up billions of years ago. The bigger asteroid was formed when the solar system was still in its initial stages of formation.
This is the reason the 4.5 billion-year-old asteroid Bennu is expected to be the key to significant information that could help scientists get to the roots of the origin of the solar system and perhaps even the universe. Scientists also expect to draw some inferences as to how asteroids can impact Earth.
OSIRIS-REx has been orbiting Bennu since 2018. From the data collected in this duration, scientists were able to infer that 5%-10% of Bennu’s weight is due to the mineral-rich water component. This will help researchers understand the role asteroids played in bringing water to Earth, which might shed light on how life evolved on the planet.
How will the mission take place?
According to NASA, the mission will be a “touch-and-go” or TAG event, in which the spacecraft will perform a sequence of three manoeuvres before it lands on a site called Nightingale.
Nightingale is the primary sampling location for the mission as it has unobstructed fine-grain material which is ideal for analysis. But the catch is that it is surrounded by building-sized rock boulders. So, the spacecraft will have to carefully touch down on the site which is about the size of a couple of parking spaces.
The spacecraft will use Natural Feature Tracking (NFT) to ensure it touches down safely by avoiding the boulders.
During its first Checkpoint manoeuvre, OSIRIS-REx will fire thrusters to adjust its position as it approaches the asteroid. In the Matchpoint manoeuvre, the spacecraft will slow down and target a trajectory to match Bennu’s rotation.
After the orbit manoeuvre, the spacecraft will change its configuration from a folded storage position to a sample collection position by extending its robotic sampling arm through a TAG Sample Acquisition Mechanism (TAGSAM).
After collecting the sample, OSIRIS-REx will fire thrusters to back away from the asteroid to reach a safer distance.
Once all these steps go as planned, scientists on Earth will check if the sample has been collected by verifying the picture of the TAGSAM head. Additionally, a spin manoeuvre will be conducted four days from now to check if sufficient sample has been collected.
The sample is expected to reach the Earth in 2023. However, NASA’s scientists believe that the mission, being first of a kind, could go wrong in many ways. Nevertheless, the spacecraft will be able to make two more attempts should something go wrong with this attempt.
You can watch the live event on NASA’s YouTube channel.