A sample from the asteroid Benu is due to return to Earth on September 24 in Utah, United States. A few grams will then head to Canada, since the Canadian Space Agency has provided essential instruments to the OSIRIS-REx mission.
What there is to know
- Samples from the asteroid Benu are due to return to Earth on September 24.
- Canada will inherit 4% of the 150 to 350 grams of samples.
- The Bénou samples contain traces of the beginning of the solar system.
The mission
The OSIRIS-REx mission (an acronym for “Regolith Explorer for Origins, Spectral Interpretation, Identification of Mineral Resources and Security”), launched in 2016, reached the asteroid Bénou in 2018. After two years of observations, samples were collected in 2020.
“The goal was to collect 60 grams of samples,” explained Mike Daly of York University during a press conference call. This objective was largely exceeded. “We think we have 250 grams, more or less 100 grams. To give a comparison, Hayabusa-2 brought back five grams from the asteroid Ryugu. »
IMAGE TAKEN FROM NASA SITE
Illustration of OSIRIS-REx preparing to take a sample from Benou in 2020
Bénou is half a kilometer in diameter and rotates in 4 hours 20 minutes, which is rather slow for an asteroid and made landing easier. The sample was taken by a 3.5 meter robotic arm, at a depth of half a meter because the soil in Bénou was softer than expected.
Bénou was named in 2013 in honor of an Egyptian deity, following a competition.
Lowering
PHOTO TAKEN FROM NASA SITE
Simulation of the landing of the Bénou sample capsule by NASA at the end of August
Four hours after the OSIRIS-REx explorer releases it, the capsule containing soil samples from the asteroid Bénou will re-enter the atmosphere. Its heat shield will reduce its speed enormously, from 45,000 km/h to less than 2000 km/h. At an altitude of 30 km, a first parachute will be released, which will further reduce the speed by half. The main parachute will then be deployed, at an altitude of 1.6 km, to slow the capsule to 18 km/h during landing. In total, the descent will last 13 minutes.
A Canadian altimeter
A laser altimeter (OLA), manufactured by MDA, made it possible to control the landing of OSIRIS-REx on Bénou, from an altitude of 7 km. It had an accuracy of 5 cm on the horizontal plane and 1 cm on the vertical plane. It consisted of a fast laser, capable of 10,000 measurements per second, and another making 100 measurements per second. The fast laser stopped working after landing. “We didn’t consider it a failure, it served its purpose,” says Mr. Daly, who is responsible for OLA.
Samples in Saint-Hubert
In exchange for OLA, Canada will inherit 4% of Bénou’s samples, or between 6 g and 14 g. “This is the first time that Canada has controlled access to samples of celestial objects,” says Kim Tait, a geologist at the Royal Ontario Museum. “Canadian researchers were able to obtain samples by directly requesting access, but that is not the same as having them here. »
The Bénou samples will be stored in Saint-Hubert from 2024, in a facility still being prepared.
PHOTO TAKEN FROM NASA SITE
The sample storage chamber in Bénou, Utah is ready.
Richard Nixon gave two Apollo lunar samples as gifts to Canada. They are located at the Canada Science Museum in Ottawa. And researchers from the University of Western Ontario and the University of Winnipeg were able to analyze samples from Apollo and the asteroid Ryugu, respectively.
Canadian institutions have also carried out experiments aboard the International Space Station, sometimes bringing space samples back to the country.
The origin of the solar system
PHOTO TAKEN FROM THE CANADIAN SPACE AGENCY SITE
Caroline-Emmanuelle Morisset, geochemist at the Canadian Space Agency
Benu was chosen because it belongs to a type of asteroid that contains the basic materials of the solar system, and also because there is a small chance that it will impact Earth by 2300 (less than 0 .05%).
Bénou would be composed of “the matter that formed the solar system,” Caroline-Emmanuelle Morisset, geochemist at the Canadian Space Agency, said during the press conference. “There may even be fragments older than the solar system. This will inform us about the origin and evolution of the solar system. Benou is also thought to contain a lot of organic molecules and water, essential ingredients for the formation of life. This will help us understand the origin of life and the importance of asteroids in the origin of life on Earth. »
PHOTO TAKEN FROM NASA SITE
Simulation of handling Bénou samples in a gas box filled with nitrogen
Unlike meteorites, the Bénou sample will not be contaminated by re-entry into the atmosphere, note Mme Morisset. “We will keep the sample under nitrogen. It is an inert gas which will prevent contamination by the atmosphere. The sample manipulations will take place in gas boxes with a terrestrial atmosphere. »
Analyzes of the sample will extend over decades, according to Mme Morisset.
Other space samples
PHOTO TAKEN FROM NASA SITE
Sample tubes left by the Perseverance probe for a return mission to Earth launched in 2027 or 2029
- The Apollo missions returned 382 kg of lunar soil.
- In the 1970s, three Soviet Luna missions returned a total of 300 g of lunar soil.
- China’s Chang’e 5 mission returned 1.7 kg of lunar soil in 2020.
- The American Stardust mission reported 1 mg of comet tail in 2006.
- In 2010, the Japanese Hayabusa mission reported 1 mg of asteroid.
- In 2020, the Japanese Hayabusa-2 mission reported 5.4 g of asteroid.
- In 2033, 500 g of Martian samples from the Perseverance mission are expected to return to Earth.
Apophis
The OSIRIS-REx mission will be extended until at least 2029 to study the asteroid Apophis. “We will have to approach closer to the Sun than planned by the initial mission for maneuvers in 2024,” said Mr. Daly. We will evaluate the performance of the probe afterwards. »
Learn more
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- 2.7 billion
- Number of Bénou measurements taken by OLA
SOURCE: YORK UNIVERSITY
- 200 to 300 million
- Initial objective of Bénou measurements by OLA
SOURCE: YORK UNIVERSITY