NASA asteroid sample mission set for launch

NASA is launching an ambitious billion-dollar science mission Thursday, sending an SUV-size, robot arm-equipped spacecraft on a two-year voyage to a nearby asteroid to map its surface, search for organic compounds, collect a precious soil sample and return it to Earth for detailed laboratory analysis.

The OSIRIS-REx spacecraft — the convoluted acronym stands for Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer — is scheduled for liftoff atop a United Launch Alliance Atlas 5 rocket at 7:05 p.m. EDT (GMT-4) Thursday. Forecasters are predicting an 70 percent chance of good weather.

Launch from complex 41 at the Cape Canaveral Air Force Station will come just one week after a fully fueled Falcon 9 rocket built by arch-rival SpaceX exploded during a pre-flight test just 1.5 miles away, at launch complex 40, rocking the area with a ground-shaking blast.

While the explosion destroyed the $62 million Falcon 9 rocket and its $195 million satellite payload, ULA engineers said the Atlas 5 and OSIRIS-REx, housed at the time inside a protective vertical processing building, were not affected and launch preparations were not interrupted.

And so, the stage is set for launch on a two-year voyage to a small near-Earth asteroid known as Bennu, believed to be a carbon rich remnant of the original cloud of gas and dust that coalesced to form the solar system 4.6 billion years ago.

Using a sophisticating mapping camera, two mineral sniffing spectrometers, a laser altimeter and a student-managed X-ray imaging system, OSIRIS-REx will study Bennu in extraordinary detail before unlimbering a robot arm in July 2020, two years after arrival in August 2018, to collect a surface sample.

OSIRIS-REx will ride into space atop a United Launch Alliance Atlas 5 rocket, seen here shortly after spacecraft installation.

United Launch Alliance

Flying in precise formation with the slowly rotating asteroid, OSIRIS-REx will extend its arm to push a clever 12-inch-wide sample collector onto the surface in a robotic high five of sorts. During the five seconds or so the collector is in contact, nitrogen gas will shoot out, stirring soil and small particles away from the surface so they can be captured.

Enough nitrogen is available for up to three sample collection attempts, but engineers are hopeful only one will be necessary. The goal is to capture at least 2.1 ounces of material and, depending on the nature of the surface and the duration of the sampling attempt, up to 4.4 pounds.

With the collected material safely stowed in a re-entry capsule, OSIRIS-REx will bid Bennu farewell in March 2021, setting off on a two-year voyage back to Earth. The 100-pound sample capsule will be released on Sept. 24, 2023, hitting Earth’s atmosphere at a blistering 27,000 mph before a gentle parachute-assisted touchdown in Utah.

From there, the samples will be flown to Astromaterials Acquisition and Curation Office at the Johnson Space Center in Houston, where Apollo moon rocks are stored, and subjected to two years of detailed analysis.

Three quarters of the material will be stored for future study and some will be distributed to Canadian and Japanese collaborators. And then, at the end of September 2025, the OSIRIS-REx mission finally will come to an end.

Mission overview video

Standing in a clean room at the Kennedy Space Center on Aug. 20, wearing protective coveralls, gloves, a face mask and hood to minimize any chance of contamination, University of Arizona principal investigator Dante Lauretta discussed the mission with two similarly-garbed reporters as engineers readied the spacecraft for the short trip to the launch pad.

The mission began, he recalled, with scribbles on a cocktail napkin in a Tucson bar.

“2004 was the concept, literally three guys in a bar sitting around saying hey, we should gin up an asteroid mission and bid this to NASA,” Lauretta said. “2025, in September, it’ll be lights out, we’re done with the program, the science papers have been published. That’s 21 years of my career. I was 33 years old when I got involved in the program and I’ll be 54 when it’s over. So it’s pretty much my professional life.”

Admiring his spacecraft, its solar arrays and robot arm folded away and its sample return capsule safely stowed, Lauretta marveled, “it’s a beautiful spacecraft; it really has behaved very well for us. So I’m happy to send it on the journey to Bennu and back. But I’m also going to miss just the awesome engineering that is the privilege of this position.”

OSIRIS-REx principal investigator Dante Lauretta of the University of Arizona-Tucson shows an enthusiastic thumbs up while discussing the mission with reporters during a visit to a clean room at the Kennedy Space Center where the spacecraft was being processed for launch.

William Harwood/CBS News

But the scientific payoff will be worth it when the largest sample of pristine extraterrestrial material brought back to Earth since the Apollo moon program is finally under the microscopes in Houston.

“OSIRIS-REx is going to help us understand how the solar system works and the nature of the bodies in the solar system,” said Jeff Grossman, OSIRIS-REx program scientist at NASA headquarters.

“It’s going to help us understand how the solar system formed. It’s going to inform our understanding for the potential for life in the solar system, on Earth and elsewhere. But it also advances our more practical goals of understanding the resources of the near-Earth solar system as well as the hazards.”

Said Jim Green, NASA’s director of planetary science: “This is a dark asteroid that we have found. We’re going to hunt it down, we’re going to orbit, we’re going to take a good look at it, and we’re going to bring back a sample.”

“This is a fantastic mission,” he said.

The Atlas 5’s Russian RD-180 first-stage engine, a single strap-on solid fuel booster and a powerful hydrogen-fueled Centaur second stage will accelerate the 4,650-pound OSIRIS-REx to an Earth-departure velocity of more than 14 miles per second before releasing it to fly on its own 55 minutes after launch.  

To change the tilt of its trajectory, OSIRIS-REx will loop around the sun once and make a close flyby of Earth on Sept. 22, 2017, using the planet’s gravity for a velocity-boosting assist. If all goes well, the spacecraft will catch up with its quarry in August 2018, precisely matching Bennu’s 63,000 mph pace around the sun.

Originally catalogued as 1999 RQ36, Bennu was discovered Sept. 11, 1999, and later renamed after an international contest won by then third-grader Michael Puzio. He suggested Bennu, an Egyptian mythological deity associated with creation and rebirth.

Bennu is roughly spherical with a diameter of about 1,614 feet and an estimated mass of about 85.5 million tons. The asteroid rotates once ever 4.3 hours and takes 1.2 years to complete one trip around the sun at distances ranging from 126 million miles to 83 million miles. It is an almost black, B-type asteroid with a density similar to coal.

It is classified as a potentially hazardous asteroid, or PHA, because its orbit carries it within five million miles of Earth’s orbit and it is large enough to survive atmospheric entry in a collision.

Bennu poses no threat to Earth for more than a century, tracking shows, but based on more than two dozen radar observations and nearly 500 telescopic studies, experts predict a 1-in-2,700 chance of impact between 2175 and 2199. Lest anyone get unduly alarmed, that means the probability of a miss is better than 99.9 percent.

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NASA asteroid sample mission set for launch