Nasa to attempt asteroid surface sample collection
Image credit: nasa
Nasa’s Osiris-Rex spacecraft will tomorrow (20 October) make an attempt to capture a sample of the asteroid Bennu in the hope that it will enable scientists to learn more about the formation and evolution of the Solar System.
If successful, Osiris-Rex will be the first US spacecraft to return samples from an asteroid and follows in the footsteps of Japan’s Hayabusa2 probe which is expected to return samples from the Ryugu asteroid upon its anticipated landing back on Earth in December.
Tomorrow (20 October), Nasa will attempt to manoeuvre Osiris-Rex down to a selected site on Bennu’s rocky and dusty surface in order to collect a 60g sample for return to Earth in 2023.
The van-sized spacecraft is aiming for the relatively flat middle of a tennis court-sized crater named Nightingale. Boulders as big as buildings loom over the targeted touchdown zone.
Bennu is considered to be a “time capsule” for the formation of the solar system, as such asteroids are considered “primitive”, having undergone little geological change from their time of formation.
Bennu was selected because of the availability of pristine carbonaceous material, a key element in organic molecules necessary for life.
Such molecules, such as amino acids, have previously been found in meteorite and comet samples, indicating that some ingredients necessary for life can be naturally synthesised in outer space.
Roger Harris, who served as project manager for Osiris-Rex, said: “Since Bennu is so far away, the operators on the ground will issue instructions to the software and then it will autonomously approach Bennu and extend its robotic arm, called the 'Touch-And-Go Sample Acquisition Mechanism' (TAGSAM).
“The solar panels will pull back safely away so they can’t touch Bennu’s surface and the Natural Feature Tracking system will enable the spacecraft to pull back before the spacecraft is in danger of colliding with a hazardous area of the 'Nightingale' landing site, which - while our best option for gathering surface material - is surrounded by massive mission-ending boulders.”
Once it drops out of its half-mile-high (0.75km-high) orbit around Bennu, the spacecraft will take a deliberate four hours to make it all the way down, to hover just above the surface.
“For some perspective, the next time you park your car in front of your house or in front of a coffee shop and walk inside, think about the challenge of navigating Osiris-Rex into one of these spots from 200 million miles away,” Mike Moreau, Nasa’s deputy project manager, said.
Contact should last just five to 10 seconds, long enough to shoot out pressurised nitrogen gas and suck up the churned dirt and gravel.
“If all goes well, TAGSAM will stow the gathered material and begin the trip home,” Harris said. “It’s exciting to know that we contributed to this mission and positively affected the development of the spacecraft and instrument software with the results of our hard work.”
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