Christmas Day for scientists who study asteroids comes in just two months when a small spacecraft carrying material from a distant mess will land in a Utah desert.
The return of the OSIRIS-REx sample container on Sept. 24 ends its primary mission to capture material from an asteroid — in this case, the carbonaceous near-Earth asteroid Bennu — and return some of its pebbles and dust to Earth.
It’s been a long time coming. This mission was launched seven years ago and has been in the planning and development phase for over a decade. To say that the scientists who fought for and carried out this mission are anxious and excited is an understatement. But there’s an added excitement with OSIRIS-REx, because scientists aren’t quite sure what they were able to pull away from the asteroid.
Touch and go
Bennu is essentially a pile of rubble, and to collect this material, the spacecraft used a unique “touch-and-go” maneuver. Immediately after the tip of a robotic arm landed on Bennu, the spacecraft fired a canister of pure nitrogen gas, causing a cloud of material to rise from Bennu’s surface. The sampling arm hovered on the surface for seconds sucking up this material before receding.
The catch is that scientists aren’t entirely sure what they have or how much of it they’ve recovered. Scientists are confident that they have collected at least 60 grams of material from Bennu, or about the mass of a Snickers bar. It is more likely that they collected at least a few hundred grams, if not more. But they won’t know until the spacecraft lands and the capsule opens.
“It certainly adds to the tension for us,” said Nicole Lunning, a planetary scientist at NASA’s Johnson Space Center in Houston.
The monsters will be met by a fleet of scientists and helicopters at the Utah Test and Training Range when it lands on the morning of the 24th. There the dusty heat shield is removed. The sample carrier is then flown to Houston’s Ellington Field the next day where it is placed in a clean room. Almost immediately, scientists will clean asteroid dust from the outside of the sample container and begin a preliminary analysis.
On Monday, Lunning led a tour of the facility where, over the course of about 10 days, Johnson Space Center scientists and technicians will carefully open the sample container and begin placing the contents into a special pizza-sized tub with eight compartments. This work will be supervised by Lunning, the primary curator of the OSIRIS-REx samples in Houston.
It will be done in a brightly lit ISO-5 cleanroom on the second floor of Building 31 in the space center, with epoxy floors and white walls. Here the samples are carefully characterized and a catalog is made of all small stones and dust particles.
OSIRIS-REx has a team of about 200 scientists dedicated to the mission, and they will have six months to conduct their initial analyzes of the material collected from the asteroid’s surface. After this time, the samples will be available to outside scientists for additional research.
Origin of life
Scientists are very careful with samples from the asteroid Bennu, because they don’t want to contaminate them with organic material from Earth. It is hoped that by understanding the material that makes up Bennu, scientists can get a snapshot of conditions as far back as the solar system’s origins, when such asteroids formed. By characterizing the organic material and minerals around it, scientists may be able to unravel some of the details about how life in the solar system originated.
For the last half century, beginning with the first stones brought back from the moon by the Apollo mission, NASA has stored its valuable materials from the solar system in meticulously maintained vaults and clean rooms at the Houston facility. As part of the Astromaterials Research and Exploration Science program, this facility houses meteorites that originated on Mars, bits of solar wind, cometary particles, and 127,000 cataloged samples of moon rocks.
“Every monster here has a story to tell,” says Eileen Stansbery, who directs the program. “Our job is to preserve these samples for scientists to use for decades to come.”