NASA launches ambitious mission to sample asteroid Bennu
Friday, September 9, 2016, 11:18 AM -
With hundreds of asteroids out in space that could pose a danger to Earth, NASA's OSIRIS-REx mission is now on course for a 7-year mission to investigate one of the largest - 101955 Bennu. The data, and sample, the spacecraft returns promises to help us respond to future threats.
Watch OSIRIS-REx liftoff
At 7:05 p.m. EDT on Thursday, September 8, OSIRIS-REx performed a beautiful lift-off from Cape Canaveral, right on schedule. Watch NASA's coverage of this incredible launch above.
Now in space, OSIRIS-REx has entered into orbit around the Sun. Roughly 1 year from now, on Sept 27, 2017, the spacecraft will catch up with Earth again, for a gravity boost towards its rendezvous with Bennu, in August of 2018.
While the science team will keep track of OSIRIS-REx as it travels, and we'll likely capture some cool pictures of Earth during the gravity assist, August 2018 is when the real work, and fun, starts with this mission.
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Why an asteroid mission?
Nearly 2 billion years ago in the vicinity of Sudbury, Ontario. 215 million years ago in northern Quebec. 66 million years ago off the Yucatan Peninsula. 50,000 years ago in Arizona. June 30, 1908 in Tunguska, Siberia. February 15, 2013 over Chelyabinsk, Russia.
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All images courtesy Wikimedia Commons
These asteroid impacts represent just a small sample of the bombardment Earth has been under, for billions of years. Some potentially kick-started life here. Others fundamentally altered the hierarchy of life on our planet. The more recent examples, especially the bolide that exploded over Chelyabinsk in February of 2013, serve to remind us there are still dangers to us out in the blackness of space, and that we must work not only to identify these dangers, but also come up with ways to protect ourselves.
OSIRIS-REx - Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer - promises to help us develop methods of protection from potentially dangerous asteroids, the over 1,700 we currently know about, and the ones we discover in the future.
Watch Below: Science @ NASA presents an overview of the OSIRIS-REx mission to potentially hazardous asteroid Bennu
If we do not learn from the past and protect ourselves in the future, we are doomed to extinction, just like the majority of the dinosaurs following the Chicxulub impact, some 66 million years ago.
What is the reason NASA chose asteroid Bennu for this mission?
101955 Bennu, which was discovered in September of 1999, is estimated at roughly half a kilometre across and based on measurements from here on Earth, scientists figure that it likely tips the scales at around 60 million metric tons.
If Bennu were to hit Earth, and there is a small chance of this happening, sometime between the 2169-2199 (roughly 1 in 2,700), it wouldn't have the effect of the ancient impacts, like Chicxulub, but it would certainly be devastating for us. Fortunately, even that 1 in 2,700 chance still means that there's a over a 99.9 per cent chance that it will miss, but with a rock the size and mass of Bennu, it's better to be safe than sorry.
OSIRIS-REx will not only give us a better idea of what Bennus is made of, but it will also test how much Bennu's orbit is affected by light pressure from the Sun (via the Yarkovsky effect), which will give us a better idea of how the asteroid's path may change in the future.
More to our benefit, the spacecraft will also test how much its presence near the asteroid affects how Bennu moves through space. This will give us an idea of how much of an effect we can have on inbound hazardous asteroids, so that we can develop ways of diverting them into much safer orbits.
Why is this important to Canada?
Canada is making a very important contribution to this asteroid sample return mission.
OLA - the OSIRIS-REx Laser Altimeter - is the spacecraft's instrument that will map the surface of Bennu. Supplied for the mission by the Canadian Space Agency and developed by Canadian companies MacDonald, Dettwiler and Associates (MDA) and Optech, this part of the mission is run by a joint Canada-US team, which includes Alan Hildebrand, from the University of Calgary, as the instrument Primary Investigator and Michael Daly, from York University, as the Deputy PI and Instrument Scientist.
According to NASA:
The OSIRIS-REx Laser Altimeter (OLA) is a scanning LIDAR (Light Detection and Ranging). LIDAR is similar to RADAR, but it uses light instead of radio waves to measure distance. OLA will emit laser pulses at the surface of Bennu, which will reflect back from the surface and return a portion of the laser pulse to the LIDAR detector. By carefully measuring the time difference between the outgoing pulse and the incoming pulse, the distance the spacecraft and the surface of Bennu can be computed using the speed of light. This allows OLA to provide high-resolution topographical information about Bennu during the mission. OLA ranging measurements will also support other instruments and navigation and gravity analyses.
Thus, this Canadian built, contributed and managed instrument will allow OSIRIS-REx to perform its primary duty. OLA will return the finest map of an asteroid ever produced, and the spacecraft can then use that map to gather its sample for return to Earth.