Early Monday morning, NASA's Orbiting Carbon Observatory 3 (OCO-3), an instrument that measures atmospheric carbon dioxide arrived at the International Space Station.

OCO-3 along with approximately 5,500 pounds of NASA cargo was launched last Saturday on SpaceX's Dragon Spacecraft. The NASA science and engineering teams cleverly assembled the Orbiting Carbon Observatory 3 (OCO-3) using spare parts from the instrument's predecessor, OCO-2, which launched in 2014 and orbits Earth independently. Since OCO-2 is still active, the two missions will be able to cross-calibrate their data.

After the arrival of Dragon spacecraft at the Space Station, astronauts used robotic arms to unpack the cargo and mount the carbon-measuring observatory on the underside of the space station facing toward Earth where it will track variations in atmospheric carbon dioxide.

That will help scientists answer questions about how and why levels of the greenhouse gas fluctuate over days, months and years.

"Our goal is to get really good data so we can make informed decisions about how to manage carbon and carbon emissions in the future," said Annmarie Eldering, the mission's project scientist at Jet Propulsion Laboratory in La Canada Flintridge.

Unlike its predecessor, OCO-3 looks at Earth's surface in three wavelengths: two for carbon dioxide, and one for the type of light your eyes see. Every molecule has a unique way that it absorbs light, almost like a fingerprint, and that's what is being exploited by this instrument. In this way, we have a continuous record of carbon dioxide levels in the atmosphere.

Besides all this, OCO-3 also is able to take a snapshot of carbon levels over an area of 50 miles by 50 miles. This will feed a bunch of scientific investigations of emission hot spots, like cities or volcanoes. It can also look at how plant activity changes over the course of a day.