How SCISAT & ABB have revealed wildfire ozone impacts

Key to this discovery were ABB technologies aboard the Scientific Satellite Atmospheric Chemistry Experiment (SCISAT-1) satellite. To learn more about ABB’s involvement in this crucial discovery, Electronic Specifier’s Harry Fowle spoke with Frederic J. Grandmont, Technology & Business Development Manager at ABB Space & Defence Systems.

Meet SCISAT

Launched in 2003, the Canadian Space Agency’s SCISAT satellite has since provided a continual stream of critical insights into the Earth’s atmospheric composition, particularly the ozone layer. This is achieved by accurately measuring chemicals that migrate upwards and potentially impact the Earth’s UV protection capabilities.

Initially only intended for a two-year mission to offer a brief overview of chemical processes, SCISAT have since exceeded expectations, marking its 21^st anniversary in orbit as of August 2024. It has now become the international standard for high-altitude atmospheric profiling. SCISAT’s orbit was specifically chosen to enhance measurements near the North Pole, where the ozone hole was identified in the mid-1980s.

How SCISAT and its ABB sensor suit has lasted two decades

SCISAT has been able to remain operation for over two decades due to a combination of robust engineering, precise orbital positioning, and effective mission management. The satellite was built with durable components that have withstood the harsh conditions of space, while careful design ensured it could continue to function long past its initial two-year life span.

Grandmont explained how ABB’s expertise owed to this longevity: “This was ABB’s first true instrument in orbit and an important project for the world of high-end space systems. While the challenging scientific requirements called for an instrument more complex than other cameras or spectrometers flown in orbit, its design could be largely based on a technology which had been tested and perfected by ABB since the 1970’s through thousands of instruments operating 24-7 at customer sites. We also brought in external experts to challenge our design choices on adaptation for space throughout the design process. Our qualification tests followed rigorous NASA standards, and we implemented redundancy on elements susceptible to fail.”

Beyond this, SCISAT's orbit and instruments were optimised to minimise wear and conserve power, allowing it to avoid unnecessary strain. Regular updates to mission protocols and careful resource management by the Canadian Space Agency also played a role, enabling SCISAT to deliver consistent data and extend its operational life far beyond initial expectations.

ABB’s FTS links wildfires to ozone depletion

Recently, SCISAT was able to make yet another impactful discovery about the Earth’s atmosphere, discovering that the intense wildfires we are experiencing each year are direct contributors to ozone layer depletion. ABB’s Fourier Transform Spectrometer (FTS) was one of the key contributing components behind this discovery.

“A spectrometer’s purpose is to measure the energy contained in different adjacent colours in light as if someone was able to isolate the rainbow colours and send each one to a solar panel to compare the power output for each. When it comes to separating infrared colours, the SCISAT FTS is by far the most powerful spectrometer in orbit. While other powerful spectrometers are able to cut an infrared light beam into thousands, SCISAT pushes the limit to 200,000 independent energy readings, well ahead of others,” explained Grandmont.

This powerful spectrometer provided scientists with 200x more resolution than typical approaches so that they can spot a wide range of ‘spectral fingerprints’ left by molecules in our atmosphere. These hidden signatures – the appearance of objects to infrared sensors – are almost impossible to spot without the bigger resolution offered by ABB’s FTS onboard SCISAT.

“These faint signatures are caused by gases present in extremely low concentrations, for example one molecule per every billion molecules of what is for the most part nitrogen, oxygen and water vapour. Nevertheless these ‘rogue’ molecules inviting themselves into the atmosphere can react chemically with the ‘good’ molecules upon random encounters and turn them into something else without any human intervention,” continued Grandmont.

The ozone layer, which shields life on Earth from harmful UV radiation, is primarily located at the top of the atmosphere, well above airliner routes. SCISAT was designed to monitor the concentration and movement of man-made CFCs (ChloroFluoroCarbons) from their release on the ground to their journey into the stratosphere. Once there, UV radiation breaks down these gases, releasing chlorine atoms that react with and deplete ozone molecules.

While the Montreal Protocol has significantly addressed the issue of CFCs, SCISAT continues to monitor atmospheric recovery and the pace at which the ozone layer repairs itself. Beyond this, the satellite has become an atmospheric sentinel, explains Grandmont.

“Acting as sentinel, it sometimes happens that the SCISAT science team can spot unexpected concentrations of new molecules appear on their radar screen. This is what happened in this case. The scientists spotted an unusual concentration of a new molecule over the pole that they eventually tracked back to recent especially large wildfire events.”

Researchers are now investigating this phenomenon by replicating the atmospheric conditions observed by SCISAT in laboratory simulations. Their goal is to understand the chemical reactions triggered by these molecules and predict their potential impact on the ozone layer.

Detection down to the parts per trillion

SCISAT’s FTS from ABB, who have since supplied other instruments for space missions, is capable of detecting gases in the atmosphere down to the parts per trillion level. This sensing power has been key to detecting and measuring all sorts of harmful gases, CFCs in particular. As it stands SCISAT is one of the only satellites with this level of capability in orbit.

Grandmont explained the importance of such ability: “(CFCs) are a set of odourless and non-toxic molecules which are great for their property to vaporise at room temperature. If you compress enough of it in a pressurised can turn it into liquid and add any other molecule of interest (such as paint – hair spray, odour scent – when breaking the pressure with the nozzle, CFCs will boil rapidly and exit the can carrying with them the molecule of interest. CFCs only act as a transporter out of the can and are disposed in the air afterward.

“The problem is that they don’t fall back to the ground or get washed out by the rain. They accumulate and over time migrate upwards towards the stratosphere. SCISAT can probe the concentration of CFCs at any altitude but most importantly it can differentiate between the different variants which have quite similar spectral signature but not when observed in detail. After the Montreal protocol, the chemist community worked to engineer a variant of the CFC that would not react chemically with the ozone. While SCISAT cannot observe the decline of the old CFC near the surface it can see the rise of the replacement molecule, track the possible existence of rogue emissions and gain important inputs on determining how much time before the ozone layer fully recovers to its 1970’s state.”

Wildfires and SCISAT’s role

As the Earth’s ecosystems change as a result of temperatures which only continue to rise, we will need to deal with the consequences of these shifts. In the case of wildfires, this rebalancing might mean moving the forest line in wildfire susceptible areas or increasing direct monitoring, or even developing new firefighting methods such as drone swarms, for example.

By products of wildfires are released directly into the atmosphere and can vary in consistency based on the forest in question and the intensity of the fire. Different forests have different substances in them, and more intense wildfires can result in higher temperatures which allow for increased combustion of different materials.

Understanding the impact of these fires is where SCISAT shines, explains Grandmont: “SCISAT is the ultimate tool to track the actual impact. By circling the earth every day, it follows relentlessly what appears in the airmass near the surface and monitors whether it sticks and accumulates there for a long time or gets cleaned up by natural processes. We know from lab experiments and physics theory that all molecules interact with infrared light by absorbing distinct colours (or photon energy) that corresponds to their microscopic geometry as if each of them had different shapes and corner to catch light particles of given size and let others through. Hence almost no molecules can go unnoticed by SCISAT. Typical spectrometers are designed to observe colours of interest corresponding to molecules of interest because it is hard and seemingly makes no sense to observe regions you do not intend to conduct science in. SCISAT was not designed this way. It captures all it can. This is what makes it so unique in discovering unexpected phenomena.”

At the heart of research, but not eternal

The valuable data from SCISAT has been shared around the world, such as within the recent UN ozone research report. These collaborations are vital in our understanding of the Earth’s atmosphere and what we can be doing to help ease our own impact.

“The SCISAT data is routinely cited in the IPCC report released every year by a group of scientists under mandate from the United Nations to provide the latest forecasts and state of play on climate. SCISAT tracks more than 70 different molecules and isotopologue variants, some of which are considered pollutants, harmful to biology and humans if accumulated in too large concentrations. As such, SCISAT provides critically vital information to climate observers much like a doctor needs a blood test to track a patient’s health,” says Grandmont.

However, SCISAT isn’t eternal and has already well-surpassed its initial lifespan. The mission is swiftly approaching its ‘unavoidable’ end of life due to aging electrical components or even something more drastic like debris hits – so what’s next?

“My hope is that the Canadian Space Agency or another space agency will take the leadership in maintaining this vital capacity and recording data for generations to come,” enthused Grandmont. Thankfully, we are already seeing increased interest from various nations in atmospheric monitoring missions.

“When generations far into the future will wonder about the changes in Earth’s atmospheric composition over the years, the data from SCISAT will be as close a reference as one could get.”