Newly Selected NASA Mission To Return Samples from Asteroid
WASHINGTON and SEATTLE — NASA’s decision to launch an unmanned probe in 2016 to retrieve samples from an asteroid is a win for, the Denver-based company on tap to build the spacecraft for the $800 million mission.
The U.S. space agency announced May 25 that it picked the asteroid-bound OSIRIS-Rex to be its next New Frontiers solar system exploration mission. The mission, led by NASA’s Goddard Space Flight Center in Greenbelt, Md., and the University of Arizona, beat out competing proposals to retrieve samples from the far side of the Moon and send a probe to the surface of Venus.
The target of OSIRIS-Rex — short for Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer — is an asteroid called 1999 RQ36. Measuring some 575 meters in diameter, 1999 RQ36 has been classified as a potentially hazardous asteroid since its orbit will bring it close to Earth in 2182.
After traveling three years to its quarry, the OSIRIS-Rex craft will spend about a year studying the asteroid before moving in to collect surface samples using a robotic arm. According to the plan, the probe will return these bits of space rock to Earth in 2023 so scientists can study them for clues about the solar system’s origin and, possibly, how life may have begun on our planet.
Jim Green, director for NASA’s Planetary Science Division in Washington, said the $800 million price tag for OSIRIS-Rex does not include the cost of launch. Green said NASA would select a rocket closer to the probe’s 2016 launch, which he said will take place from Florida’s Cape Canaveral Air Force Station.
The Lockheed-built probe will be equipped with a suite of four instruments built by Goddard, the University of Arizona, Arizona State University and the Canadian Space Agency.
The probe will also carry a sample-collecting device that will stir up dirt and small gravel to be captured and sealed for a 2023 return to Earth using hardware and procedures used on the Lockheed Martin-led Stardust comet sample-return mission in 2006.
OSIRIS-Rex will be the United States’ first asteroid sample-return effort and only the second mission in history to retrieve samples from an asteroid. Japan’s Hayabusa spacecraft successfully returned tiny grains of the asteroid Itokawa to Earth in June 2010.
Itokawa is a relatively run-of-the-mill stony asteroid. 1999 RQ36, however, appears to be packed full of carbon-based material. If an asteroid seeded Earth with life’s building blocks long ago, as many scientists suspect, it likely looked a lot like 1999 RQ36.
“We’re going for something rich in organics, which might have had something to do with life getting started,” OSIRIS-Rex principal investigator Mike Drake, of the University of Arizona, told reporters May 25. “That’s the idea — time capsule, containing probably the building blocks of life.”
The OSIRIS-Rex probe is not NASA’s only mission to an asteroid. The space agency’s Dawn spacecraft is currently closing in on Vesta, the second-largest asteroid in the solar system, and will arrive at the space rock later this year. But Dawn will simply orbit Vesta, not gather samples. It will also eventually leave Vesta and rendezvous with Ceres, the largest asteroid in the solar system, for a similar orbiting campaign.
After it launches in 2016, OSIRIS-Rex will take about three years to reach 1999 RQ36. But it will not pluck its samples immediately. Rather, the spacecraft will study the asteroid for about a year, so scientists can better understand its characteristics, choose the best sampling site and map out a good strategy.
The need for such a prolonged observation period is one lesson learned from the Hayabusa mission, which had to do quite a bit of troubleshooting, Drake said.
“They did not have enough time at their target asteroid, Itokawa, to really understand the environment they were operating in and safely conduct proximity operations leading to sample return,” Drake said.
After performing its reconnaissance, OSIRIS-Rex will gradually move closer to its sampling site, and the arm will extend to collect at least 60 grams of material. The spacecraft will never actually land on 1999 RQ36.
“We kiss the surface,” Drake said.
The acquired sample will be stored in a capsule, which will land at the U.S. military’s Utah Test and Training Range in 2023. The capsule’s design will be similar to that used by NASA’s Stardust spacecraft, which returned the world’s first comet particles from comet Wild 2 in 2006.
The OSIRIS-Rex spacecraft, meanwhile, will be redirected into a new solar orbit, likely with enough fuel to perform another mission in the future if NASA wishes, researchers said.
Once the asteroid bits come down to Earth, researchers will study them to learn as much as they can about the solar system’s formation and the organic molecules that asteroids may be ferrying throughout the solar system.
But OSIRIS-Rex also has other potential benefits, researchers said.
“The knowledge from the mission also will help us to develop methods to better track the orbits of asteroids,” Green said.
Specifically, the mission should help scientists accurately measure the “Yarkovsky effect” for the first time. This phenomenon is the tiny push the sun gives an asteroid, as it absorbs sunlight and re-emits that energy as heat.
If scientists hope to predict a potentially hazardous asteroid’s path, they must understand the Yarkovsky effect, researchers said. OSIRIS-Rex should help refine 1999 RQ36’s orbit, allowing scientists to get a better handle on its trajectory and possibly understand how to mitigate or prevent potential Earth impacts.