OSIRIS-REx: The Mission – Infographic

An overview of the OSIRIS-REx asteroid sample-return mission. (Credit: Canadian Space Agency)

An artist's rendition of the OSIRIS-REx spacecraft collecting a sample from the asteroid Bennu with its robotic arm. The following details about the mission are presented:

The purpose of the OSIRIS-REx mission is to: 

• Collect a sample from a near-Earth asteroid called Bennu, and return the sample to Earth for study;
• Help scientists better determine the orbit of the asteroid; and 
• Acquire knowledge about the asteroid's composition, which could give clues about how planets formed and how life on Earth began.

These are the scientific objectives of the mission:

• Collect a sample and return it to Earth;
• Map the asteroid;
• Determine Bennu's physical and chemical properties;
• Measure the orbit deviation caused by sunlight (the Yarkovsky effect); and
• Compare observations with data from telescopes.

What is Canada's contribution to the mission?

The OSIRIS-REx Laser Altimeter (OLA) is the Canadian contribution to the spacecraft. OLA made a 3D map of Bennu and helped mission experts select the best site from which to collect the sample.

Why was asteroid Bennu chosen for this mission?

A number of factors make Bennu different from other asteroids. First of all, it is not too far away from Earth. Every six years, Bennu's orbit brings it near Earth – less than 450,000 kilometres away.

Asteroids less than 200 metres wide spin very quickly, which makes it difficult for a spacecraft to safely interact with them. Bennu is nearly 500 metres in size and revolves once every 4.3 hours, slowly enough to collect a sample.

Lastly, Bennu's physical characteristics are of interest to scientists: they want to analyze Bennu's chemistry and mineralogy to learn more about its composition and how it compares to other asteroids.

Here is the mission timeline:

The launch took place in September 2016. The OSIRIS-REx spacecraft arrived at its destination in 2018. It spent more than a year and a half collecting data and preparing for sample collection. In October 2020, the sample was collected.

The sample is scheduled to return to Earth on September 24, 2023. Bringing a sample to Earth will allow scientists to study Bennu for decades using highly sophisticated instruments and techniques.