NASA's GLIDE heliophysics mission moves closer to launch: All you need to know

NASA's Global Lyman-alpha Imager of the Dynamic Exosphere (GLIDE) mission has moved into its next phase after passing a critical review - Key Decision Point C - that assessed the mission's preliminary design and project plan to achieve launch by its target launch readiness date of 2025.

Led by the University of Illinois Urbana-Champaign, the GLIDE mission will survey the exosphere, the outermost layer of Earth’s atmosphere that keeps on changing in response to space above and Earth below. The exosphere stretches from about 310 miles above the surface to at least halfway to the Moon and plays an important role in Earth’s response to space weather, the changing conditions in space driven by the Sun.

The mission will provide insights into how Earth’s exosphere is influenced by changes in space, including the solar wind and improve the scientific community's ability to predict the impacts of the Sun’s activity.

NASA's GLIDE will observe the natural process of atmospheric escape, which occurs slowly at Earth. Atmospheric escape is defined as the loss of planetary atmospheric gases to outer space and it played an important role in the story of Mars's atmosphere, where it siphoned water from the planet’s surface.

The spacecraft will orbit the Sun at Lagrange point 1, a gravitational balance point between Earth and the Sun, to image the entire exosphere. It will ride to space along with the Interstellar Mapping and Acceleration Probe, or IMAP, which will explore the boundaries of the heliosphere - the volume of space filled with particles streaming out from the Sun - and study how it interacts with the local galactic neighborhood beyond.

Planned for launch in 2024, IMAP will help scientists better understand the nature of interplanetary space, which is dominated by solar wind. The mission also aims to learn more about the generation of cosmic rays in the heliosphere.