5 Goals of the OSIRIS-REx Mission to the Asteroid 'Bennu'

NASA Goddard Space Flight Center
NASA Goddard Space Flight Center

After almost two years in space, NASA's groundbreaking spacecraft OSIRIS-REx is now on its final approach to its target—the asteroid Bennu, a mountain-sized, near-Earth object that scientists believe holds the secrets to the origins of the solar system.

When it reaches Bennu on December 3, 2018, it will match the asteroid's speed as it orbits the Sun (63,000 mph), and fly in formation with it for the next couple of years as it maps and surveys the surface. Then, on July 4, 2020, OSIRIS-REx will reach out to Bennu with a robotic arm, scoop up a sample from the surface, and store it in a capsule. The next year, the craft begins heading back to Earth, where in 2023 it will eject the sample-containing capsule over the Utah desert for retrieval.

It's the first time in history this kind of sample retrieval has ever been attempted, and scientists are pretty excited about it. The mission objectives of OSIRIS-REx are embedded in its name: the Origins Spectral Interpretation Resource Identification Security-Regolith Explorer. The craft has five scientific instruments tasked with carrying out these objectives. Let's break it all down.

1. ORIGINS: BRINGING A TIME CAPSULE FROM THE BIRTH OF THE SOLAR SYSTEM BACK TO EARTH

"This is really what drives our program," Dante Lauretta, the principal investigator of the mission, said in 2016, shortly before the spacecraft was launched from Cape Canaveral. "We're going to asteroid Bennu because it is a time capsule from the earliest stages of solar system formation, back when our planetary system was spread across as dust grains in a swirling cloud around our growing proto-star." Bodies accumulated in the cloud, many getting water ice and organic material—key compounds that led to the habitability of Earth and the origin of life. Bennu is one such body. By taking a hopefully carbon-rich sample of the asteroid and bringing it home, planetary scientists will be able to study in a laboratory setting a pristine cache of the building blocks of Earth.

Lauretta described sample return as being the forefront of planetary exploration. If Bennu is a time traveler from the distant past, sample return is time travel to the distant future: As new laboratory techniques and technologies are developed, scientists in coming years can use them to analyze the samples with far more sophistication than we're capable of today. To appreciate how massive an advance might be in store, consider that 50 years ago, computers were only just being introduced to the field of geology here on Earth. Now we can study the composition of many bodies in the solar system.

2. SPECTRAL INTERPRETATION: ANALYZING BENNU'S COMPOSITION

Since Bennu's discovery in 1999, scientists have used the best telescopes on Earth and in space to study the asteroid. As such, they have an extraordinary data set from which to work, and believe they have a pretty good handle on the asteroid's composition. The spacecraft, up close and personal with the asteroid, will use its spectrometers and cameras to provide "ground truth" to the distant observations of telescopes. Scientists will be able to see how well their predictions matched reality. What they got correct will have confirmation; what they got wrong can be used to refine their models. All of this can then be applied to thousands of other objects in the solar system.

3. RESOURCE IDENTIFICATION: EYEING FUTURE MINING OPERATIONS

Lauretta told Mental Floss that when OSIRIS-REx was first conceived, resource identification was "cool science fiction." The idea of going to asteroids and mining them for material was the sort of thing people in some Jetsons-like future would be able to do, but not us. Today, however, companies are lining up for the chance to begin celestial mining operations. OSIRIS-REx will pioneer the technologies and capabilities necessary to provide detailed global analysis of an asteroid's surface. They will be able to focus on composition and mineralogy with an eye toward identifying regions of interest. It will be, in other words, creating the sorts of prospecting maps once seen in the Old West—only this time for an off-world ore-rush.

4. SECURITY: STUDYING BENNU'S TRAJECTORY TO AVOID POTENTIAL ASTEROID COLLISIONS

Earth's orbit around the Sun is startlingly perilous. Bennu is only one of several near-Earth objects that have a small-but-not-impossible chance of colliding with this planet in the 22nd century. (The odds are 1 in 2700, which is about the same as your odds of dying by exposure to smoke or fire. That's a pretty terrifying figure when you consider the destruction and damage that such an asteroid impact might cause, and that people die in house fires all the time.)

Scientists will use the data returned from OSIRIS-REx to study something called the Yarkovsky Effect. As asteroids go about their orbit, they absorb energy from the Sun and emit that energy as heat. That emission essentially acts as a small, natural asteroid thruster, and changes an asteroid's trajectory over time. In a 12-year period, the Yarkovsky Effect changed Bennu's position by more than 115 miles. If researchers can better understand the causes and effects of the phenomenon, they can apply that knowledge not only to Bennu but also to thousands of objects throughout the solar system. If some object is headed our way, we can know about it sooner—and perhaps find a way to stop it.

5. REGOLITH EXPLORER: UNDERSTANDING HOW SURFACE PARTICLES BEHAVE IN MICROGRAVITY

Regolith is the blanket of dust and gravel on the surface of many celestial bodies. Scientists don't quite understand random mechanics in a microgravity environment. Even if Bennu's sample collection arm is unsuccessful—it can make three attempts—Lauretta said the effort alone pushes the boundaries of research: "By the act of putting our device on the surface of the asteroid to collect the sample, in and of itself we are performing a fantastic science experiment."

Editor's note: This story originally ran in 2016 and was updated in August 2018.

The Leonid Meteor Shower Peaks This Weekend—Here's the Best Way to See It

NASA/Getty Images
NASA/Getty Images

The Leonid meteor shower will be making its annual appearance in the sky this weekend. As NPR reports, the best time to catch it will be late Saturday night into Sunday morning (November 17-18)—so if you really want to catch this dazzling light show, you may want to drink some coffee to help you stay up.

The waxing gibbous Moon will dull the meteors’ shine a little, so plan to start stargazing after the Moon has set but before dawn on Sunday. (You can use timeanddate.com to figure out the moonset time in your area. The site also features an interactive meteor shower sky map to track visibility conditions.)

If you'll be in parts of the South or Midwest this weekend, you're in luck. Florida, Alabama, Mississippi, Nebraska, and Nevada are expected to enjoy the best view of the Leonids this time around, according to Popular Mechanics.

The Leonids occur every year around November 17 or 18, when Earth drifts across the long trail of debris left behind by the comet Tempel-Tuttle. The comet takes 33 years to complete its orbit around the Sun, and when it reaches perihelion (its closest approach to the Sun), a Leonid storm may occur depending on the density of the comet's existing debris. This sometimes results in hundreds of thousand of meteors streaking across the sky per hour, viewable from Earth. The last Leonid storm occurred in 2001, but Earth may not see dense debris clouds until 2099, according to the American Meteor Society.

This year, if skies are clear and you can secure a secluded spot away from city lights, you might be able to see around 15 to 20 meteors per hour. They travel at 44 miles per second “and are considered to be some of the fastest meteors out there,” NASA says. They’re also known for their “fireballs”—explosions of light and color—which tend to last longer than a typical meteor streak.

[h/t NPR]

Two Harvard Scientists Suggest 'Oumuamua Could Be, Uh, an Alien Probe

ESO/M. Kornmesser
ESO/M. Kornmesser

An odd, cigar-shaped object has been stumping scientists ever since it zoomed into our solar system last year. Dubbed 'Oumuamua (pronounced oh-MOO-ah-MOO-ah), it was first seen through the Pan-STARRS 1 telescope in Hawaii in October 2017. 'Oumuamua moved at an unusually high speed and in a different kind of orbit than those of comets or asteroids, leading scientists to conclude that it didn't originate in our solar system. It was the first interstellar object to arrive from somewhere else, but its visit was brief. After being spotted over Chile and other locales, 'Oumuamua left last January, leaving lots of questions in its wake.

Now, two researchers at Harvard University bury a surprising suggestion in a new paper that analyzes the object's movement: 'Oumuamua could be an alien probe. Sure, why not?

First, astrophysicists Shmuel Bialy and Abraham Loeb argue that 'Oumuamua is being driven through space by solar radiation pressure, which could explain its uncharacteristic speed. But for that theory to work, they calculate that the object must be unusually thin. Bialy and Loeb then analyze how such a slender object might withstand collisions with dust and gases, and the force of rotation, on its interstellar journey.

Then things get weird.

"A more exotic scenario is that 'Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization," they write [PDF]. They suggest that ‘Oumuamua could be be a lightsail—an artificial object propelled by radiation pressure—which also happens to be the technology that the Breakthrough Starshot initiative, of which Loeb is the advisory committee chair, is trying to send into space. "Considering an artificial origin, one possibility is that 'Oumuamua is a lightsail, floating in interstellar space as a debris from an advanced technological equipment,” they write.

Their paper, which was not peer-reviewed, was posted on the pre-print platform arXiv.

Loeb is well known for theorizing about alien tech. He previously suggested that intense radio signals from 2007 could be the work of aliens who travel through space on solar sails. However, Loeb acknowledged that this theory deals more with possibility than probability, The Washington Post noted. “It’s worth putting ideas out there and letting the data be the judge,” Loeb told the paper last year.

[h/t CNN]

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