OSIRIS-REx: Playing Tag with an Asteroid

Let’s talk about OSIRIS-REx, the spacecraft that landed on an asteroid, collected a sample, and then lifted off to bring it all back home to us on Earth. It’s pretty incredible that we were able to navigate 200 million miles away from Earth to an asteroid in orbit around our sun, land on it, and then lift off again. So, here’s some information about this historic event.

First off, OSIRIS-REx seeks to find answers on where we came from. After all, you’re probably asking why we even decided to visit a barren place like an asteroid in the first place.

Asteroids are the leftover debris from the formation of the solar system.  The asteroid OSIRIS-REx is focused on is called Bennu and its loose surface material, called “regolith,” may have precursors to the origin of life and the Earth’s oceans.

Why did we choose Bennu out of all the asteroids?

Scientists chose Bennu because of its composition, size, and proximity to Earth. Asteroids like Bennu have not significantly changed since they formed nearly 4.5 billion years ago. Because of this, we hope to find organic molecules that have led to the origin of life on Earth.

Getting to Bennu was no easy task. It took two years just to reach Bennu, launching in 2016 and arriving in mid-2018. Once it arrived to the asteroid, it used rockets to match the speed of Bennu and went into orbit. It then took a year to map and survey the surface.

It eventually touched the surface for five seconds, blasted a jet of nitrogen gas to dust up the surface, collected samples from the roiled up material, then lifted off to head back home.

OSIRIS-REx actually did several recon circles to determine a proper landing site and a rehearsal before attempting to actually land and takeoff.

OSIRIS-REx used a device called a Touch-and-Go-Sample-Acquisition-Mechanism, or TAGSAM, to collect a sample of regolith from Bennu. After that burst of nitrogen gas, the dusted up surface was collected by the TAGSAM and eventually placed into stowage for return.

After collection, OSIRIS-REx fired a thruster to lift off. The mission team then spun the TAGSAM and measured the difference in inertia from an empty TAGSAM before and compared it to after collection. Once it was determined it have enough sample volume, OSIRIS-REx was allowed to drift away from Bennu until March 2021 when it will depart and head back home.

Since the successful collection, scientists will study the samples remotely by studying the collection site’s before-and-after images as well as taking a photo of the sample canister. 

OSIRIS-REx is an acronym which stands for Origins, Spectral Interpretation, Resource Indentification, Security, Regolith Explorer.  These terms were used to define the science investigation of the asteroid sample.  It was then realized that these all spelled out OSIRIS-REx.

This mission was over a decade of planning to reach a primordial rock that has witnessed our solar system’s entire history. 

For up-to-date news and images please visit: https://www.asteroidmission.org/

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