There’s an asteroid heading towards a near-Earth encounter in 2018 that’s dangerous enough to influence NASA engineers to send a spacecraft to meet it, scan it, get close enough to vacuum samples from its surface and bring them back for study. Why? The pass-by in 2018 may alter its course enough to cause a collision when it returns on its next trip around the sun. Shouldn’t the vacuum suck up the whole thing now when it has a chance?
The asteroid, discovered in 1999 by the The Lincoln Near-Earth Asteroid Research (LINEAR) project, is named Bennu. Bennu is a big asteroid - approximately 500 meters in diameter, weighing over 60 million tons and heading to Earth’s vicinity at over 100,000 km per hour (62,000 mph). Put that all together and you have an impact potential of 3 billion tons of explosives or enough to wipe out most life on the planet.
It gets worse. Bennu’s path is difficult to predict because it suffers from the Yarkovsky effect – a trajectory shifting caused by it absorbing and releasing solar heat. Is there any good news?
We estimate the chance of impact at about one in 2,700 between 2175 and 2196.
That’s Dante Lauretta, a professor of planetary science and cosmochemistry at the University of Arizona's Lunar and Planetary Laboratory, explaining why the OSIRIS-REx mission, which he is principle investigator for, is not getting much attention in the lead-up to its launch on September 8th and eventual return with a sample in 2023. NASA is promoting it as a chance to study a 4 billion-year-old asteroid that has regularly passed by and may have had a previous big influence on Earth.
Bennu is a carbonaceous asteroid, an ancient relic from the early solar system that is filled with organic molecules. Asteroids like Bennu may have seeded the early Earth with this material, contributing to the primordial soup from which life emerged. We believe Bennu is a time capsule from the very beginnings of our solar system. So the sample can potentially hold answers to the most fundamental questions human beings ask, like 'Where do we come from?'
How about a fundamental question like “Will anyone still be here in 2196?”
So NASA isn’t worried because no one working there now will be around in 150 years or so when Bennu could strike fast and hard. Lauretta thinks humans will have the technology by then to either destroy or deflect a dangerous asteroid, although the only options he could come up with were nuclear missiles or tractor beams.
Lauretta started research for the OSIRIS-REx Mission in 2004 and says he’s now feeling "anxious and proud" but "It's a tense moment for all of us.”
Maybe we should write a letter of apology to future generations for not equipping OSIRIS-REx with a bigger vacuum.