NASA’s newest mission, GOLD, will explore the ever-changing boundary between Earth and space.
No hard and fast line divides Earth's upper atmosphere from outer space. Instead, the little understood region where one fades into the other responds both to terrestrial weather in the lower atmosphere below and the tumult of space weather from above. This dynamic region has historically been difficult to observe; 60-400 miles above the surface, it’s too low to easily study with satellites and too high for aircraft and scientific balloons. On Jan. 25, 2018, NASA set out to change that with the launch of the Global-scale Observations of the Limb and Disk, or GOLD, instrument, hosted aboard a commercial communications satellite. From geostationary orbit, GOLD observes Earth's interface to space. Space is not completely empty: It’s teeming with fast-moving charged particles and electric and magnetic fields that guide their motion. At the boundary between Earth’s atmosphere and space, these particles and fields - the ionosphere - co-exist with the upper reaches of the neutral atmosphere, called the thermosphere. The two commingle and influence one another constantly. GOLD inspects this interplay and the forces responsible for the day-to-day changes in this critical boundary layer. Watch the videos to learn more.