Illustration of the OSIRIS-REx pattern return capsule passing by means of Earth’s ambiance
NASA Goddard Area Flight Heart/CI Lab
Bits of the asteroid Bennu are coming again to Earth. NASA’s OSIRIS-REx spacecraft took samples of the asteroid in 2020 that are scheduled to reach on Earth on 24 September.
OSIRIS-REx launched in 2016 and entered orbit round Bennu in 2018. Scientists selected Bennu as a goal primarily due to its comparatively small distance from Earth – on the time of launch, it was about 225 million kilometres away, and within the intervening years it received as shut as 50 million kilometres from Earth.
Due to its common shut approaches, Bennu is taken into account a near-Earth object (NEO). It’s not anticipated to smash into our planet anytime quickly, however there’s a few 0.057 per cent probability of a collision within the subsequent 300 years. Bennu is about 490 metres throughout, so if it did crash into Earth it will trigger vital injury.
One motive to review Bennu is to determine how you can shield Earth from it and related asteroids. However one other is that it is likely one of the most primitive house rocks we all know of. “Asteroids like Bennu are time capsules from the early photo voltaic system, particles that’s left over from the formation of the photo voltaic system,” says Anjani Polit on the College of Arizona, a part of the OSIRIS-REx group.
Such asteroids most likely clustered collectively to type our photo voltaic system’s planets, so we will use them to know how the planets shaped and grew. Bennu specifically hosts massive concentrations of carbon, the primary constructing block of natural molecules – which in flip are the constructing blocks for all times as we all know it.
“We’re fairly positive that there shall be natural molecules in these samples,” says OSIRIS-REx scientist Michelle Thompson at Purdue College in Indiana. “Learning these natural molecules may assist us perceive what organics have been round within the early photo voltaic system that would have seeded life on Earth.”
Comparable samples have already been returned by Japan’s Hayabusa2 spacecraft, which visited an asteroid known as Ryugu. A key part of the researchers’ purpose of understanding the historical past of the photo voltaic system shall be evaluating mud samples from these two objects.
“Let’s say you’re a customer to Earth and also you need to be taught all about Earth’s geologic historical past, so that you choose up one rock – you’re by no means going to have the ability to be taught that,” says Thompson. “Going to a couple of completely different asteroid actually opens up a complete new world to essentially perceive the range of fabric that was round 4.5 billion years in the past”, in regards to the time when the photo voltaic system shaped.
On 24 September, the day will begin early for the OSIRIS-REx group. Within the wee hours of the morning, the group’s engineers will make a name about whether or not it’s protected to launch the pattern capsule. If they provide the “go”, it is going to be despatched hurtling in direction of Earth from about 102,000 kilometres away, greater than 1 / 4 of the space to the moon. It’ll journey for about 4 hours earlier than slamming into the ambiance at round 44,000 kilometres per hour. Throughout its descent, it is going to be protected and slowed by a warmth defend and two parachutes till it touches down within the Utah desert.
“As soon as we launch the capsule, there’s nothing else we will do besides wait and hope all the things goes easily,” says Polit. “All these years of labor, all of it comes right down to that 13-minute descent by means of the ambiance.” If the capsule can’t be launched on 24 September, it is going to be two years earlier than researchers have an opportunity to strive once more.
If it may be launched, although, the OSIRIS-REx spacecraft will proceed on in direction of an prolonged mission on the asteroid Apophis. On Earth, the pattern it drops shall be instantly scooped up and despatched to Houston for scientists to analyse. “I actually really feel like a child on Christmas Eve,” says Thompson. “I’m about to get up and get all these presents of samples from Bennu.”
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