NASA’s OCO-3: A New View of Carbon

Since about the start of the Industrial Revolution, we have seen CO2 levels in the atmosphere increase by about 30%. Human activity is causing a tipping of the scales, this very fine delicate balance that we have and what we call the carbon cycle here.

The key motivation for the OCO-3 experiment is to continue this record of carbon dioxide. OCO-2 was built to last two years. We’ve had it up there for four years, but there’s always a risk it’s not gonna survive, so OCO-3 goes on the space station in the spring. We’d like to have measurements that cover a long duration, and OCO-3 is going to help add to that record.

OCO-3 is gonna specifically produce a dataset of carbon dioxide measurements. We’d like to be able to keep an eye on this atmospheric CO2, where did it come from, where’s it going, and how is it related to other global processes.

When plants are doing photosynthesis, they emit a little bit of light, and we can sense that light in our measurements, so we have a measure of plant photosynthesis activity in combination with the carbon dioxide.

Plants use CO2 for growing. They absorb it into the leaves, they convert CO2 and water into sugar that they use to store the energy to grow later. The combination of these measurements can tell us about the relationship between this net uptake of CO2 over time and how that is being governed by photosynthesis.

OCO-2 measured every day, the same time of day. With OCO-3 on the space station, we’re gonna sample from sunlight to sundown, and so now we can learn about carbon cycle through different parts of the day, and that’s really important, because plants respond to sun, so we need to see them behaving across the day.