Christmas Day for scientists who study asteroids comes in two months, when a small spacecraft will land in a Utah desert with material from a distant debris pile.
The Sept. 24 return of the OSIRIS-REx sample container will cap its primary mission of capturing material from an asteroid—in this case, the carbonaceous near-Earth asteroid Bennu—and return some of its cobbles and dust to Earth.
It’s been a long time. The mission, which began seven years ago, has been in the planning and development stages for more than a decade. To say that the scientists who fought for and carried out this mission were both anxious and excited is an understatement. But there’s an added frisson with Osiris-Rex, because scientists aren’t entirely sure what they’ve made of the asteroid.
Bennu is essentially a pile of debris, and to collect this material, the spacecraft used a unique “touch-and-go” strategy. Shortly after a robotic arm touched down on Bennu, the probe fired a canister of pure nitrogen gas and a cloud of material rose from Bennu’s surface. The sampling arm lingered on the surface for several seconds to draw up this material before retracting.
The catch is that scientists don’t know exactly what they got or how much they recovered from it. Scientists are confident that Bennu collected at least 60 grams of material, or the mass of a Snickers candy bar. More likely, they have collected at least a hundred grams, if not more. But they won’t know until the spacecraft lands and opens the capsule.
“It adds tension to us, for sure,” said Nicole Luning, a planetary scientist at NASA’s Johnson Space Center in Houston.
The samples will be met by a flotilla of scientists and helicopters at the Utah Test and Training Range when they land on the morning of the 24th. There the dusty heat shield is removed. The sample carrier will be flown the next day to Ellington Field in Houston, where it will be placed in a clean room. Almost immediately, scientists will remove asteroid dust from the outside of the sample container and begin preliminary analysis.
On Monday, Lunning led a tour of the facility, where in about 10 days, Johnson Space Center scientists and technicians will begin carefully opening the sample container and placing it in a special pizza-sized tray with eight compartments. The work will be overseen by Lunning, the primary curator of OSIRIS-REx samples in Houston.
This is done in a shiny ISO-5 clean room with epoxy floors and white walls on the second floor of Building 31 at the space center. Here, the samples will be carefully photographed, and all the small rocks and dust particles will be added to make a catalog.
About 200 scientists are dedicated to the mission on OSIRIS-REx, and they have six months to conduct a preliminary analysis of material collected from the asteroid’s surface. After this time, the samples will be available to outside scientists for further research.
Origin of life
Scientists are very careful with samples from the asteroid Bennu because they don’t want to contaminate them with organic matter from Earth. By understanding the material that makes up Bennu, scientists hope to get a snapshot of the conditions leading up to the origin of the Solar System when such asteroids formed. By imaging organic matter and its surrounding minerals, scientists may be able to tease out some details about how life originated in the Solar System.
For the past half century, since the first rocks brought back from the moon by the Apollo missions, NASA has stored precious materials from the solar system in carefully maintained vaults and clean rooms at its Houston facility. As part of its astromaterial research and exploration science program, the facility houses 127,000 cataloged samples of Martian meteorites, bits of solar wind, cometary particles, and lunar rocks.
“Every sample here has a story to tell,” said Eileen Stansberry, who directs the program. “It’s our job to preserve these samples for scientists to use for decades to come.”