A tiny sample from a multibillion-year-old asteroid could hold clues to the early solar system, says scientist

Researchers at the University of British Columbia are preparing for a small sample from a multibillion-year-old asteroid to arrive in their lab. 

Pacific Centre for Isotopic and Geochemical Research director Dominique Weis expects a sample of up to a few hundred milligrams from the asteroid Bennu to arrive by the end of November.

"Bennu's constituent materials haven't undergone significant chemical changes over the past 4.5 billion years," Weis said in a news release. "Finding out what Bennu is made of will give us a window into the early solar system and what gave rise to how our solar system turned out to be."

Samples from Bennu arrived on Earth on Sept. 24. They were collected during a seven-year mission, and delivered via the OSIRIS-REx spacecraft to the U.S.

Scientists have estimated the capsule holds 250 grams from the carbon-rich asteroid, give or take 101 grams — a large margin of error, Weis said. 

OSIRIS-REx was launched in 2016 and reached the asteroid two years later. After identifying a suitable location, it lowered a robotic arm vacuum into the surface in 2020 to extract the third and largest sample ever taken from an asteroid in the first mission of its kind for NASA. 

Some of the sample spilled and floated away when the spacecraft scooped up too much and rocks jammed the container's lid during collection three years ago. 

"We are getting the samples directly from NASA," Weis said. "One of us is going to have to fly to Houston and go pick up the sample because we want to carry them and not ship them by a courier."

Practice makes perfect

Working on Bennu asteroid samples will be the first time Weis' lab has analyzed "pristine" extraterrestrial material — samples that have come straight from space, as opposed to meteorites that have fallen through Earth's atmosphere and landed on the surface, altering their physical and chemical composition. 

Her team has been working with NASA and the University of Arizona to prepare for the sample's arrival.

"We have analyzed test samples for over a year with a composition comparable, we think, to Bennu," Weis told On The Coast host Gloria Macarenko. "We have practised a lot."

She said the success of the study will depend on how much usable material they receive — it has to be in perfect condition, and can't be contaminated or disturbed during its journey to Vancouver. 

The sample will come in powder form, but will be reduced into a liquid solution for examination. Weis said they'll process reference materials with known chemical makeups to ensure quality control.

Not contaminating the sample is important, so the scientists will be working in what's called a clean-lab, where the air and fume hoods have, respectively, just 1,000 or 100 particles of less than 0.5 microns in diameter per cubic foot. For comparison, a human hair is about 50 microns in diameter. 

"Our team is a little anxious about it," Weis said. 

"It's very exciting and we're very proud to have been selected and be part of this mission."