Backgrounder Article from  Canadian Space Agency

Canada's Contribution to the OSIRIS-REx Asteroid Sample Return Mission

Canada is partnering with the National Aeronautics and Space Administration (NASA) on OSIRIS-REx, the first US-led mission to return a sample from an asteroid to Earth. Since asteroids are made of primal material left over after planets formed, the mission will help scientists investigate the formation of our planets and solar system, the origin of water and organic material on Earth, and improve our understanding of asteroids that could impact Earth. OSIRIS-REx marks the first time Canada is participating in an international mission to return an extraterrestrial sample to Earth.

Overview of the mission

Under the Origins-Spectral Identification-Resource Identification-Security-Regolith Explorer (OSIRIS-REx) mission, NASA will launch a spacecraft to an asteroid named Bennu and use a robotic arm to retrieve samples of material. OSIRIS-REx is part of NASA's New Frontiers Program, which will explore the solar system with frequent, medium-class spacecraft missions that conduct high-quality, focused scientific investigations. NASA is investing $800 million in this 14-year mission (excluding the launch vehicle).

OSIRIS-REx will be launched in late 2016 and will reach the asteroid in 2018. It will then study Bennu's geology for about 8 months. Once the sample location is chosen, the spacecraft will approach the surface and—without landing—extend its robotic arm to collect at least 60 g of material from the asteroid's surface. The sample will be returned to Earth in 2023.

The OSIRIS-REx Mission is led by Principal Investigator Dante S. Lauretta of the University of Arizona, supported by a science team of Co-Investigators, with project management at NASA's Goddard Space Flight Center and development partnership with Lockheed Martin Space Systems.

OSIRIS-REx's Destination: Asteroid Bennu

The target asteroid, Bennu (formerly known as Near-Earth Object (NEO 101955) 1999 RQ36), is an accessible volatile and organic-rich remnant from the early Solar System with a one in 2700 risk of impacting Earth in about 200 years. Observations using telescopes have revealed Bennu to be a rich in carbon, unusually dark in colour, and unlike any samples in meteorite collections.

Carbonaceous asteroids like Bennu are the direct remnants of the original building blocks of the terrestrial planets in our Solar System. Scientists believe they are primitive objects that have changed little from their time of formation. The presence of complex organics in meteorites has led to speculation that similar meteorites from asteroids seeded the early Earth with the building blocks of life. Their chemical and physical nature, distribution, formation and evolution are fundamental to understanding planet formation and the origin of life.

Bennu also has a striking circularly symmetric shape (like a spinning top) that probably formed when the asteroid rotated fast enough for rocks to tumble from its poles to pile up at its equator. Similar shapes are common amongst near-Earth asteroids. Understanding this geology and what it has done to Bennu's internal structure is a mission goal. OSIRIS-REx will also measure the magnitude of the Yarkovsky effect (how sunlight can alter Bennu's orbit over time) and give researchers a better understanding of Bennu's motion so as to better define its orbit and more accurately predict its chances of collision with the Earth.

Canada's Contribution

Through funding from the Canadian Space Agency (CSA), Canada's contribution to the mission is an OSIRIS-REx Laser Altimeter (OLA). This is an advanced lidar (Light Detection and Ranging) system that is a hybrid of the lidar on the Canadian weather station of NASA's Phoenix Mars Lander, and an instrument flown on the 2005 US Air Force eXperimental Satellite System-11 (XSS-11). OLA will scan the entire surface of the asteroid to create a highly accurate, 3D model of Bennu, which will provide mission scientists with fundamental data on the asteroid's shape, topography (distribution of boulders, rocks and other surface features), surface processes and evolution.

OLA uses a receiver and two complementary lasers to provide the information beamed back to Earth. The instrument's high-energy laser transmitter will be used for scanning from further distances (1-7.5 km from the surface of the asteroid). The low-energy laser will be used for rapid imaging at shorter distances (500 m to 1 km) to contribute to a global topographic map of the asteroid, as well as local maps to assist scientists in selecting the best sites for sample collection.

As the prime contractor for the CSA, MacDonald, Dettwiler and Associates Ltd. (MDA), together with its industrial partner, Optech, designed the instrument and will build and test it. The principal investigator for the Canadian science team is Dr. Alan Hildebrand of the University of Calgary. Dr. Michael Daly from York University is the deputy principal investigator and instrument scientist for OLA. The team also includes Dr. Ed Cloutis, University of Winnipeg; Dr. Rebecca Ghent, University of Toronto; and Dr. Catherine Johnson, University of British Columbia.

In exchange for providing the OLA instrument to the mission, the CSA will own 4% of the total returned sample, thus providing Canada's scientific community with its first-ever direct access to a returned asteroid sample. The CSA's total investment in OSIRIS-REx for the full life cycle of the mission is $61 million (including taxes) over 15 years. The technology that went into building OLA is also expected to generate spin-offs, such as airborne lidar for terrestrial topographic mapping, resource management, visions systems for robotic mining and geomatics.

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