3, 2, 1.
And Liftoff of OSIRIS-REx.
Its seven year mission to boldly go to the asteroid Bennu and back.
Loren: That Atlas V rocket is carrying NASA’s latest spacecraft, the OSIRIS-REx.
The probe is on a mission to reach a near-Earth asteroid.
Once it gets there, OSIRIS-REx will grab a sample from the space rock and bring it back
to Earth.
And what’s in that sample could tell us a lot about the early Solar System and maybe
how life formed here on Earth.
That’s because asteroids are considered tiny snapshots of the primitive Solar System.
Most of the planets and moons have undergone a lot of geological activity since they first
formed 4.5 billion years ago.
Asteroids haven’t changed all that much since then.
So they still contain the same chemical makeup of the Solar System when it first got started.
Studying those chemicals can tell us if the building blocks for life — like organic
molecules and amino acids — were present from the very beginning or if they showed
up later on.
To figure this out, NASA is targeting an asteroid named Bennu.
But what makes this space rock so special?
Well it’s a little bit like Goldilocks: everything about it is just right.
For one, it’s in an ideal location.
To make good time, NASA wanted an asteroid traveling on an Earth-like orbit between 1.6
AUs and 0.8 AUs.
It’s also a good size for getting a sample.
An asteroid that’s too small can spin pretty fast, causing any loose particles on its surface
to shoot out into space.
Bennu’s big enough so that its spin isn’t out of control.
And finally, it’s made up of the right stuff.
NASA researchers wanted an asteroid rich in carbon.
Those kinds of asteroids are thought to be the most ancient and “unchanged” since
the early days of the Solar System.
That means its samples could contain the early molecules that led to Earth life.
Sampling Bennu may be the main priority, but OSIRIS-REx will also help us better understand
if asteroids are going to hit us in the future.
During its mission, OSIRIS-REx will study something known as the Yarkovsky effect.
It’s a way that the Sun can manipulate the course of an asteroid.
The Sun emits solar radiation, which can actually push on an asteroid and slowly change its
long-term orbit.
That makes it hard for astronomers to predict exactly where an asteroid is going to be in
100 years.
So when OSIRIS-REx is at Bennu, it will study the Sun’s effect on the asteroid, allowing
astronomers to make better orbital models.
It’s going to be a while before OSIRIS-REx sees any action though.
The spacecraft will cruise through space for the next two years.
During that time, the probe will come back by Earth to get a boost from our planet’s
gravity.
That will put OSIRIS-REx on the right path to start approaching Bennu by September 2018.
As it approaches, the spacecraft will start mapping the surface of Bennu.
Thanks to early radar observations, NASA is pretty sure there is loose material on Bennu’s
surface.
But OSIRIS-REX needs to find the right spot to scoop it up.
Over a two-year period, NASA will select 12 sites that could be good for sampling, and
then narrow it down to two final sites.
Once they have the one they want, the spacecraft will try to “tag” the asteroid in July
of 2020.
OSIRIS-REx will move in close to Bennu and deploy the TAGSAM.
It’s a tiny robotic arm with a sampler head on the end.
The arm will touch the surface of Bennu and give it a whiff of nitrogen gas.
That will cause any loose materials to shoot up into the sampler head.
It’s a quick process that only takes 5 seconds.
But if successful, NASA hopes to pick up 60 grams of material.
That will be the largest sample to come back from space since the Apollo missions.
NASA can do up to three tag attempts in case one doesn’t work.
But eventually, OSIRIS-REx will have to head back to Earth in March of 2021.
That puts the spacecraft back at Earth in September of 2023.
A capsule containing the sample will fall back to our planet and land softly in the
Utah desert.
And when scientists open up that capsule, they’ll be one step closer to getting answers
about how our galactic neighborhood came to be.