A Nasa spacecraft is set to deliver asteroid samples to Earth after almost seven years of deep space travel.
The Osiris-Rex spacecraft landed on asteroid Bennu on October 21, 2020, to collect samples that could help scientists gain insights into how the solar system was formed 4.5 billion years ago.
The first asteroid sample return mission by the US space agency is expected to return to Earth on September 24.
“As Osiris-Rex flies by Earth, it will release its sample return capsule into the atmosphere,” Nasa said in a statement on Friday.
“In the remaining months before the return, the Osiris-Rex team is rehearsing and refining procedures to recover the sample, which dates from the early formation of our solar system, while protecting it from contaminants.
“The pristine material from Bennu – rocks and dust collected from the asteroid’s surface in 2020 – will offer generations of scientists a window into the time when the Sun and planets were forming about 4.5 billion years ago.”
When the spacecraft touched down on the asteroid, a large rock was preventing the container holding the samples to close properly, causing some dust and rock samples to escape into space.
To save the mission, Nasa instructed the return capsule to close ahead of time and store more than 60 grams of samples.
“Given the complexity of the process to place the sample collector head on to the capture ring, we expected that it would take a few attempts to get it in the perfect position,” Rich Burns, Osiris-Rex’s project manager, said at the time.
“Fortunately, the head was captured on the first try, which allowed us to expeditiously execute the stow procedure.”
Bennu was first discovered in 1999 and is said to be formed from materials that date back billions of years.
A parachute will be deployed upon re-entry and the capsule will descend and land in a Utah desert.
Recovery crews will secure the sample return capsule and transport it to a clean room.
“Additionally, crews will collect soil and air samples all around the landing capsule. These samples will help identify if any minute contaminants contacted the asteroid sample,” Nasa said.
“Once the capsule is inside the building with the portable clean room, members of the team will remove the heat shield, back shell, and other components to prepare the sample canister for transport to Houston.”
Only Japan so far has succeeded in asteroid-return missions.
Both of Japan’s Hayabusa missions successfully delivered material from two different asteroids. However, the first mission brought back grains that showed only ordinary chondrites, the most common type of meteorite.
China has completed a Moon sample return mission in the past.
The UAE is also working on a mission to explore asteroids, with the MBR Explorer spacecraft scheduled for launch to the main asteroid belt between Mars and Jupiter in 2028.
It is not a sample return mission, but the spacecraft will fly past six asteroids to study them and then attempt a landing on the seventh one.
The asteroid belt is rich with $700 quintillion worth of minerals such as iron, gold and nickel.