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Frequently asked questions – OSIRIS-REx

The OSIRIS-REx mission

What is OSIRIS-REx?

OSIRIS-REx is the first NASA-led mission to return a sample from an asteroid to Earth. The target asteroid, Bennu, is a pristine, carbon-rich asteroid, believed to be a fragment from the solar system formation that may help answer questions about how our solar system formed and how life on Earth began.

What does OSIRIS-REx stand for?

Origins, Spectral Interpretation, Resource Identification, Security - Regolith Explorer.

What is Canada's role in the OSIRIS-REx mission?

Canada contributed a laser instrument known as OLA (the OSIRIS-REx Laser Altimeter), which is funded by the Canadian Space Agency (CSA). The CSA also supports scientists and engineers on OLA’s development and operations team, as well as scientists from Canadian institutions who are part of the OSIRIS-REx science team. In exchange for providing the OLA instrument, Canada will receive 4% of the total returned sample.

When did OSIRIS-REx launch?

OSIRIS-REx was launched on , at 7:05 p.m. ET aboard an Atlas V rocket at the Cape Canaveral Air Force Station, Florida.

What are the main phases of the mission?

Overview of the mission's important dates

Is OSIRIS-REx the first mission to return a sample from an asteroid?

No. The first mission to successfully return a sample of an asteroid to Earth was Japan's Hayabusa mission. Launched in , the mission returned a small sample in .

Is OSIRIS-REx the first US mission to visit an asteroid?

No. NASA's first spacecraft to visit an asteroid was the Near Earth Asteroid Rendezvous-Shoemaker spacecraft, which landed on the asteroid Eros on . OSIRIS-REx is Canada's first participation in an asteroid sample-return mission.

About Bennu

How did the asteroid Bennu get its name?

In , Michael Puzio, a nine-year-old student in grade three in North Carolina, USA, won an international student contest to give the asteroid a friendlier name. Michael suggested the name because he imagined the spacecraft's robotic arm and solar panels look like the neck and wings of Bennu, the Egyptian deity often depicted as a grey heron.

How big is Bennu?

Bennu is roughly 500 metres in diameter. For comparison, the CN Tower in Toronto, Ontario, is 553 metres high.

Where is asteroid Bennu?

Unlike most asteroids, which are located in the asteroid belt between the orbits of Mars and Jupiter, Bennu travels through space on an elliptical orbit between Venus and Mars.

Why did scientists choose to study Bennu?

Bennu is both an interesting and accessible target. When selecting an ideal asteroid for the OSIRIS-REx mission, researchers needed their target to be wider than 200 metres to ensure that the spacecraft could safely approach to collect loose material from the asteroid’s surface - asteroids with smaller diameters rotate too quickly. Bennu is about 500 m in diameter, about the same as the height of the CN Tower (553 m), and its orbit makes it feasible for a spacecraft to reach it and return to Earth within a reasonable timeframe.

Asteroid fragments recovered on Earth (meteorites) are exposed to extreme temperatures when entering the atmosphere, baking away key scientific clues. Scientists believe that, when collected in space, pristine asteroid samples may contain organic molecules like amino acids - the basis for proteins and DNA. This means that an impact from an asteroid could have seeded the early Earth with the building blocks of life.

About Asteroids

What is an asteroid?

Asteroids are small, rocky bodies in our solar system. They are made up of the remnants of the primitive building blocks that created the terrestrial planets in our solar system. Most of them are located in between the orbits of Mars and Jupiter in a region known as the "asteroid belt."

What's the difference between an asteroid, a comet, a meteor and a meteorite?

Asteroids are composed mainly of rock and metals, while comets are made of ice, dust and small rocks. An object becomes a meteor if it enters Earth's atmosphere. Since meteors leave visible streaks across the sky, they are often known as shooting stars. The term "meteorite" refers to solid debris that survives entry and impact with the ground.

[Illustration] Comet, meteor or meteorite?

Are asteroids dangerous?

No significant asteroid impact threats have been detected for at least the next hundred years or so.

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