NASA has chosen two new science proposals for nine-month concept studies to advance our understanding of how the particles and energy in space – shown here flowing from the Sun in an illustration of the solar wind – affect the fundamental nature of space. One proposal will ultimately be chosen to launch along with NASA’s upcoming Interstellar Mapping and Acceleration Probe in October 2024. Credits: NASA

NASA has selected two SmallSat missions – a study of Earth’s outer most atmosphere and a solar sail spaceflight test mission – to share a ride to space in 2025 with the agency’s Interstellar Mapping and Acceleration Probe (IMAP).

The missions – the Global Lyman-alpha Imagers of the Dynamic Exosphere (GLIDE) and Solar Cruiser – were selected as Solar Terrestrial Probes (STP) Missions of Opportunity. GLIDE will help researchers understand the upper reaches of Earth’s atmosphere – the exosphere – where it touches space. Solar Cruiser demonstrate the use of solar photons for propulsion in space.

The launch of the IMAP mission in 2025 to the first Lagrangian equilibrium point (L1), about 1 million miles towards the Sun, will be a pathfinder for NASA’s new RideShare policy. With the policy, the agency’s Science Mission Directorate (SMD) will plan – from the inception of major missions – to take advantage of excess launch capacity and provide increased access to space for SmallSats. IMAP will help researchers better understand the interstellar boundary region, where the solar wind and the solar magnetic field it transfers to the edge of the solar system collide with galactic material and the galactic magnetic field.

Focusing on small satellites and tech demonstrations helps prove the capabilities of these smaller missions and pairing them with existing missions for launch provides more avenues for learning about the solar system and developing innovative technical capabilities.

“The study of the solar influence on interplanetary space and the area around our Earth has made great advances just in the past decade,” said Thomas Zurbuchen, associate administrator for science at NASA Headquarters in Washington. “I’m confident the next decade promises even more new discoveries and historic technology innovations.”

The science selection was made competitively from proposals to help better understand the fundamental nature of space and the interaction between space and Earth’s environment. As the selected science mission, GLIDE will study variability in Earth’s exosphere by tracking far ultraviolet light emitted from hydrogen. The exosphere is the outer region of Earth’s atmosphere that touches space – a region where atoms can escape Earth. Observing the global structure of the exosphere requires a telescope that is outside of the outer reaches of the atmosphere, which extend almost to the Moon. The IMAP launch trajectory to the inner Lagrangian point, the point of the Earth-Sun system that provides an uninterrupted view of the Sun, will provide just such a perspective for the GLIDE mission and is ideally suited for the first continuous observations of the exosphere and its variations in response to solar storm disruptions.

GLIDE will fill a measurement gap, as only a handful of comparable ultraviolet light images have previously been made from outside the exosphere. The mission will gather observations at a high rate, with a view of the entire exosphere, ensuring a global and comprehensive set of data. Understanding the ways in which Earth’s exosphere changes in response to influences of the Sun above or the atmosphere below, will provide us with better ways to forecast and, ultimately, mitigate the ways in which space weather can interfere with radio communications in space.

The principal investigator for GLIDE is Lara Waldrop at the University of Illinois at Urbana-Champaign. The GLIDE investigation is budgeted for $75 million.

For more information about NASA’s Heliophysics Division, visit

The Complete Story, courtesy of Grey Hautaluoma