Saving Earth from space
HOW WE CAN USE OBSERVATIONS FROM ORBIT TO PROTECT OUR PLANET FROM DISASTER
IT MIGHT NOT look it, but our planet is a fragile place. A delicate balance of pressure, temperature and gases keeps us alive as our atmosphere lets in enough heat for us to thrive, but not too much that we get too toasty. For many years our planet has looked after itself with ease. Now, with humans on the scene, things are changing more than ever, from climate change to mass deforestation. If our planet is going to survive long into the future it’s going to need our help.
Fortunately, we’ve got plenty of missions that are working for the benefit of our world already. Using observation satellites in orbit, scientists have been monitoring Earth for decades, watching how the planet pulsates and changes over time. From orbit we can watch how species migrate, identify and predict environmental changes, and even fix problems.
A great example of this was the global effort to repair a hole in the ozone above the Antarctic back in 1987. Two years prior, scientists had discovered that chemicals known as chlorofluorocarbons (CFCs) — produced by fridges and aerosols, among other things — were causing the hole to grow. As a result countries around the world agreed to phase out the use of CFCs as part of the Montreal Protocol.
In early 2018, NASA announced that its Aura satellite had watched the hole successfully close, with it expected to fully repair as early as 2060 or as late as 2080. It was proof that we could work together to change the planet for the better. Aura is part of a broader NASA project called the Earth Observing System (EOS). This program, which began in 1997, has seen NASA launch missions and instruments into orbit. This has included the groundbreaking Landsat series of satellites, which have provided surface images of the whole globe. Then there’s the Terra mission that launched in 1999 and studies clouds, sea ice and more from orbit. Most of these satellites are in polar orbits, meaning they orbit the planet from top to bottom as Earth rotates below and gives them a global view.
Planning for the EOS began back in the 1980s, with NASA keen to regularly fly instruments for at least 15 years. “Human activity has altered the condition of the Earth by reconfiguring the landscape, by changing the composition of the global atmosphere, and by stressing the biosphere in countless ways,” they noted in a handbook in 1993. “There are strong indications that natural change is being accelerated by human intervention.”
More than two dozen missions have been launched as part of the EOS to date. Among