NASA To Investigate Earth-Space Boundary, Space Weather With New ICON Satellite

Even though Earth is largely protected from the harsh radiation of open space by the layers of the atmosphere (especially ozone) that covers the planet, space weather can still impact life. For example, large solar flares and coronal mass ejections create disturbances in Earth’s magnetic field and among the charged particles of the ionosphere, which in turn can affect electronic communication on Earth, affect low-Earth satellites by making them electrically charged, and possibly even disrupt on-ground power grids.

To better understand the relationship between the ionosphere and the layers of the atmosphere extending below it all the way to the surface of the world, NASA plans to launch a new satellite. Scheduled for a Dec. 8 launch, “the Ionospheric Connection Explorer, or ICON, a low-Earth-orbiting satellite… will give us new information about how Earth’s atmosphere interacts with near-Earth space — a give-and-take that plays a major role in the safety of our satellites and reliability of communications signals,” the space agency said Wednesday.

“The conditions in our space environment — space weather — is something we need to be able to forecast. It’s difficult to predict conditions in the ionosphere tomorrow based on what we measure today,” Thomas Immel, principal investigator for the ICON mission from the University of California, Berkeley, said in a statement on NASA’s website.

The Earth-space boundary is commonly thought to be the Karman line, which is 100 kilometers (about 62 miles) above the surface. At that height, the atmosphere is too thin for regular aircraft to fly, but there is still an atmosphere, becoming thinner as you go farther from the planet. Being above the ozone layer means particles here feel the full brunt of space radiation, and many elements exist in their unstable, reactive atomic forms instead of the neutral molecular forms in the atmosphere closer to Earth.

This rarified neutral atmosphere (the reactive compounds there cause a faint glow, called airglow) shares space with the ionosphere, which is made up of charged particles and ions that result as the ultraviolet portion of sunlight breaks down particles further, removing electrons from molecules and atoms. This region is influenced by both the space weather from above it and by weather conditions below on Earth.

The ionosphere is where the International Space Station orbits Earth, as do many low-Earth orbit satellites. This charged layer is also important for communication signals, such as the GPS system. ICON will fly above the ISS orbit, at a height of about 350 miles above Earth’s surface.

Doug Rowland, mission scientist for ICON at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in the NASA statement: “ICON aims to understand how Earth’s weather modifies space weather. We’re looking at how the weather that we live in — rain, heat, snow, thunderstorms, hurricanes — affects the space environment above us.”

The satellite will carry four instruments to undertake its mission objective. Three of those instruments will focus on studying the airflow, while a pair of identical copies of the fourth will study the ionized gas in the immediate vicinity of the spacecraft.