A Canadian-made instrument is vital to asteroid sample return mission

Canadian scientists will be given a share of the rare samples from an asteroid that's due to return to Earth this weekend by NASA's OSIRIS-REx mission.

It's Canada's reward for providing a vital instrument that mapped the asteroid and helped identify the place for the spacecraft to grab the sample.

OSIRIS REx left Earth in 2016 on a seven-year return trip to asteroid Bennu, which orbits the sun between Mars and Jupiter. At only about 500 metres across, Bennu is a conglomeration of rocks and boulders loosely held together by gravity, otherwise known as a flying rubble pile.

The Canadian instrument, called OSIRIS-REx Laser Altimeter (OLA), bounced pulses of laser light off the surface of Bennu to scan and produce a 3D map of the entire object with a resolution that can pick up details as small as five to seven centimetres. Then a second laser was used at close range to make much higher resolution images in order to decide where the spacecraft would gather its samples.

When the first closeup images came in, scientists were surprised to see how many rocks and boulders covered the surface — it literally was a pile of rubble. This presented a challenge for the spacecraft's sampling arm, which had to avoid the boulders and find a flat spot to scoop up dust and small pebbles.

OLA provided the crucial information to guide the spacecraft down to a prime spot near the asteroid's north pole called Nightingale, only 10 metres across, where about 250 grams of material was successfully collected.

Because of Canada's participation in the mission, our scientists will receive four per cent of the total sample for analysis. NASA will save at least 70 per cent of the total sample for future research. Minus the Canadian allotment, the rest will go to scientists around the world, including Japan, the U.K. and to various U.S.-based institutions.

Those pristine pieces of the asteroid are extremely old. The asteroid is thought to be made up of leftovers from the original cloud of dust and gas that gave birth to our solar system more than four billion years ago.

Planets such as Earth and Mars have changed over time due to weathering and geological processes. But the smaller asteroids have remained unchanged for billions of years, making them time capsules from the past.

The final part of the mission will be critical and dangerous as the capsule containing the samples enters the Earth's atmosphere at hypersonic speed, and the friction it will encounter means it will be surrounded by super-hot plasma. It will also experience powerful G-forces as it decelerates and feels the shock of parachutes opening, before a hard landing on the great salt basin in Utah.

Once on the ground, if it survives the landing, the capsule will be quickly put into a clean container then flown to the Johnson Space Centre in Houston. There, the OSIRIS-REx team will open it in an ultra-clean facility designed to prevent contamination from Earth.

These pieces of a distant space rock will be studied for years as scientists look at the chemical composition, search for organics — the building blocks of life — and try to put together a picture of our early solar system.

This is not the first time a Canadian laser instrument has flown in space. A Canadian instrument called MET, short for Meteorological Station, flew aboard the Phoenix Mars lander in 2008. It used a laser that shone straight up from the ground to study reflections from the clouds in the Martian atmosphere. 

Canada has a long history of building instruments for space studies. We were the third country to have a satellite in orbit with Alouette 1 in 1962, the Radarsat Constellation mission has been mapping the surface of the Earth in high resolution detail, and a Canadian-built Alpha Particle X-ray Spectrometer aboard the Curiosity rover on Mars is revealing the chemistry of Martian rocks. There are also a couple of Canadian instruments on the new James Webb Space Telescope.

Canada has provided much more than astronauts and the Canadarm to the space program. This asteroid sample return mission is just the latest in a long legacy of doing good science in space.