As many readers of SpaceQ already know, Canada has access to portions of the asteroid Bennu due to our participation in the NASA-led OSIRIS-REx mission (Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer).
The Canadian Space Agency (CSA) contributed funding to the OSIRIS-REx Laser Altimeter (OLA), in exchange for 4% of the total returned sample. OLA mapped the surface of Bennu for a year and assisted scientists with choosing the touch-and-go sample site near Bennu’s north pole, informally known as Nightingale. OLA’s principal investigator was the University of Calgary’s Alan Hildebrand, with York University’s Michael Daly (in Toronto) serving as deputy PI and instrument scientist. Support also came from instrument developers MDA Space and Optech.
The concept for OLA was first developed in 2008, as a recent York video about the mission stated. OSIRIS-REx launched on Sept. 8, 2016, and OLA was turned on in 2018. The spacecraft’s sample collection was performed on Oct. 20, 2020, and then the sample was sent back to Earth in a separate return capsule during a flyby on Sept. 24, 2023. (A follow-on mission with the same spacecraft, known as OSIRIS-APEX, was slated to visit asteroid Apophis in 2029 – but its funding was cancelled for fiscal year 2026, suggesting that mission may not go ahead.)
Bennu successfully yielded more than double what scientists had hoped for: 121.6 grams, instead of 60. The sample was brought from its landing location at the Utah Test and Training Range, roughly 130 km west of Salt Lake City, to a clean room at NASA’s Johnson Space Center in Houston. There, scientists took apart the collection device and found preliminary evidence of carbon and water, according to the agency. Parts of the sample have subsequently been distributed to museums for display to the public, as well as the international research team.
York received a sample, for a few weeks, under this arrangement. That is how SpaceQ received an exclusive in-person “visit” to Bennu in June courtesy of Jim Freemantle, project manager for OLA. Already, much has been yielded from the sample long before it arrived at an undisclosed location on York’s campus. For example, Freemantle participated in a Meteoritics & Planetary Science paper published in June 2024, which was led by OSIRIS-REx principal investigator Dante Lauretta at the University of Arizona.
The paper detailed that Bennu’s dust includes carbon, nitrogen, organic compounds and a surprise find of magnesium-sodium phosphate not spotted by the spacecraft. The “surprise” suggests that the half-kilometre Bennu may have been part of a small world with an ocean, prior to splitting off on its own.
At York, the sample was encased in a tiny case, about the size of a coin collector’s enjambment, but the case was filled in nitrogen to keep the relative humidity low. Using an atomic force microscope, a needle akin to an old-fashioned phonograph (but much smaller) was used to scan the surface. A laser beam bounced off the needle on to the surface of the sample; the deflection redirected the laser to a sensor, creating a movement in the microscope.
“The idea is that the machine will move the head up and down to keep the laser in the same place,” Freemantle said. Freemantle was using the device to measure the thermal properties of the sample, by measuring the resistance of the current. This sample, incidentally, is 50 microns in size; a human hair is 75 microns. But even at that small scale, inevitable research challenges always arise.
“The tricky thing is that unfortunately, the surface isn’t completely flat, and so as the probe moves over the surface, it sort of gets lumps and bumps,” Freemantle explained. “When it goes down into a valley, more of the probe touches the surface – so more heat flows … I have to try and remove that from the signal. That’s something I’m working on right now, trying to find a technique that will allow me to, I guess, deconvolve the lumps and the bumps from the real signal.”
The thermal properties of Bennu are important to researchers for a few reasons, he continued. One is trying to figure out the surface: trying to relate the small pebbles collected in the sample to the larger boulders that were seen on the surface – not to mention the entire asteroid itself. A second reason is to determine the influence of the sun on the surface of the asteroid, which creates heating influencing the orbit of the asteroid. This is known as the Yarkovsky effect.
Freemantle emphasized, however, that the Bennu samples are not only useful for composition – but also for aging. His sample has been polished for analysis, but those portions that have been unpolished may show evidence of micrometeroid impacts even on a tiny scale. There’s a well-used technique in planetary science known as crater counting, in which scientists examine the number of craters in a given area on a body such as the moon or Mars. In principle, the more craters there are, the older a surface is believed to be (with some variants). Bennu’s pocked samples may also reveal age on a smaller scale, he said.
Freemantle, a computer scientist by training, has a background in remote sensing and image processing. About 40 years ago, he worked with imaging spectrometers that were on aircraft, with the Ontario Centre for Remote Sensing. Today, he serves as a research associate at York. This means that Freemantle wears a number of hats; he is mentor to students, manager of multiple labs, a troubleshooter of shipping items into the facilities, and a procurement specialist.
“It was a huge, huge challenge and it really got me out of my comfort zone,” Freemantle said of taking on his current position. “Fifteen years ago, if you’d asked me to go and try and manipulate the helium hose, [I would joke] ‘That’s hardware! That’s hardware.’ But now, I feel reasonably comfortable carrying the wrench. I’ve also been given the opportunity to do things like tendering and procurement, because when we bought all this equipment, I was part of the team that wrote the RFPs [requests for proposals].”
Freemantle emphasized that a good part of his job is showing other students the way of lab management, for those that will need to take over their own labs and equipment one day. “Those are the kind of things that when I was a graduate student, my supervisor allowed me to sort of get my hands dirty a little,” he added.
Aside from Freemantle’s mentorship, certain students at York may receive paid, hands-on experience with up to 20 months of co-op; institutional participants have included MDA, Canadensys and CSA. Statistics from York are available at this website. Space engineering is a relatively small portion of the total number, but unique, according to York officials.
Given Freemantle’s affiliation as lab manager, the visit to “Bennu” also generously included a tour of several facilities at York’s Centre for Research in Earth and Space Science (CRESS). CRESS builds on decades of space research – including missions that flew in space. Lasers are just one facet of the research, but they are an important facet highlighted even on the literal walls of the facility, which were adorned with patches, posters and other souvenirs.
To name just a few examples: York’s Allan Carswell served on the NASA Atmospheric Lidar Working Group, which argued for “a multiuser shuttle lidar facility” to study Earth’s atmosphere back in 1979 – two years before shuttle flew. As it turned out, such a facility was finally tested 25 years later in 1994 with the Lidar In-space Technology Experiment (LITE), which operated for 53 hours aboard STS-64. The lidar found “cloud structures, storm systems, dust clouds, pollutants, forest burning and surface reflectance” while studying Earth’s atmosphere, according to NASA.
York also developed the lidar instrument aboard the NASA Phoenix mission that landed on Mars in 2008, which found dust and clouds that had water ice in them – along with snow precipitation of snow. “It doesn’t actually reach the surface, but they have these, what they call, ‘fall streaks’. And sometimes we see them on Earth,” Freemantle explained; he was project manager for that instrument.
Aside from this work, Canadian Steve MacLean taught part-time at York University from 1980 until 1983, just before he joined the government astronaut corps in 1984. His own laser research entailed “electro-optics, laser-induced fluorescence of particles and crystals, and multi-photon laser spectroscopy”, according to CSA. This was prior to him serving as program manager for the Advanced Space Vision System and Laser Camera System for Canadarm and Canadarm2, the latter of which is still operational on the International Space Station.
The tour of CRESS included a visit to the Canadian Space Simulation Facility, which received a major equipment grant in 2016-17. “It allows us to simulate the conditions of space, and other environments like Jupiter, Mars and the moon,” Freemantle explained. “In order to do that, we have got a very large chamber … we can take it down to the low pressures of space, but it’s been used primarily so far to simulate Mars – which is 8 millibars.”
Numerous other instruments are available in the labs near Freemantle’s office. A few examples:
- A ball mill allows researchers to take rocks and – like a paint shaker – use ceramic balls to produce powder in about 15 minutes, creating a dusty environment that could be used for regolith simulant. (The university also purchases commercial simulant, if required for the experiment.)
- Another scanning electron microscope, in use for students and other researchers, is available for studies such as those of meteorites; during the time of the visit, the lab was looking at a frozen sample returned from a lake, which was kept frozen for analysis.
- A cryogen-free measurement system allows researchers to measure physical properties of materials, while allowing samples to be cooled as low as six degrees or seven degrees Kelvin.
- A “minus-40” freezer, which as its name implies allows samples to be stored at low temperatures. The freezer is very close to a CRESS environmental chamber, allowing for samples to be very quickly moved back and forth for safe analysis.
