NASA's OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security - Regolith Explorer) spacecraft, which was launched to a near-Earth asteroid named Bennu, is returning to Earth with a sample. The sample from Bennu, formerly known as 1999 RQ36, will be studied to understand how planets formed and how life began, and to know more about asteroids that could impact Earth.
When will the sample return to Earth?
The sample capsule will parachute down into the Utah desert on September 24, 2023. This will be a major milestone for the United States because the successful return of the sample to Earth will mark the country's first-ever mission to return an asteroid sample to Earth.
OSIRIS-REx was launched on September 8, 2016, and reached asteroid Bennu in 2018. The spacecraft has spent seven years in space.
Why is delivering the asteroid sample to Earth a challenge?
Delivering the asteroid sample to Earth is a challenging mission, because OSIRIS-REx will have to protect the sample from heat, vibrations and earthly contaminations.
In a statement released by NASA, Mike Moreau, deputy project manager at NASA's Goddard Space Flight Center, said once the sample capsule touches down, a team will be racing against the clock to recover it and get it to the safety of a temporary clean room.
What will happen after the sample reaches Earth?
A new laboratory for the material has been built at NASA's Johnson Space Center in Houston. Over the next six months, the OSIRIS-REx team will practise and refine the procedures needed to recover the asteroid sample in the Utah desert and transport it to the new laboratory.
At the new laboratory, scientists will unpack the sample, distribute up to a quarter of it to the OSIRIS-REx science team around the world for analysis, and curate the rest for other scientists to study.
The above image shows members of NASA's OSIRIS-REx curation team practising with a mock glove box at the Johnson Space Centre. This team will be among the first to see and handle the sample the OSIRIS-REx spacecraft is returning to Earth from asteroid Bennu.
When planets formed in the past, some ancient materials from the source were left. These remnants are asteroids, and may contain molecular precursors to life. By studying asteroid fragments that have naturally reached the ground as asteroids, scientists have learnt a lot about these celestial bodies.
Scientists wish to understand if asteroids played a role in delivering molecular precursors to life to Earth's surface over four billion years. For this, a pristine sample from space, free from terrestrial contaminants, is required.
According to NASA, the most fragile rocks observed on Bennu probably would not have survived passage through Earth's atmosphere as meteorites. Dr Jason Dworkin, OSIRIS-REx project scientist at NASA Goddard, said the two things pervasive on Earth, which can severely alter meteorites when they land on the ground, are water and biology. Therefore, a pristine sample is important to obtain insights into the development of the solar system.
The OSIRIS-REx spacecraft will fly by Earth on September 24, and release its sample return capsule. This will mark the end of the primary mission of OSIRIS-REx.
According to NASA, the capsule is estimated to hold about a cup of Bennu's material, which will weigh about 250 grams. The sample return capsule is expected to enter Earth's atmosphere at 10:41 and ET, and touch down inside the targeted area 13 minutes later.
After touchdown, the sample return capsule will be secured and taken to a portable clean room. Next, the heat shield, back shell and other components will be removed, to prepare the sample canister for transport to Houston.