The Atmosphere-Space Transition Region Explorer (ASTRE) -- Using in situ Measurements on a Low Perigee Satellite to Understand How the Upper Atmosphere and Magnetosphere are Coupled

Robert F Pfaff Jr, NASA Goddard Space Flight Center, Heliophysics Sci. Div., Greenbelt, MD, United States, Douglas E. Rowland, NASA Goddard Space Flight Center, Greenbelt, MD, United States, Roderick A Heelis, University Texas Dallas, Richardson, TX, United States and James H. Clemmons, The Aerospace Corp, Los Angeles, CA, United States
The Atmosphere-Space Transition Region Explorer (ASTRE) is a proposed NASA MIDEX mission designed to carry out an unprecedented study of the interaction between the Earth’s atmosphere and the ionized gases of space within the transition region/boundary layer between 150-250 km. ASTRE addresses a universal process – the coupling of ionized and neutral gases – which is important for understanding not only how the Earth’s upper atmosphere/lower ionosphere “works”, but also how such ion and neutral gases exchange energy. By directly gathering measurements “at the end of the line” of the sun-upper atmosphere chain, ASTRE provides the critical missing link in our knowledge of the transfer, dissipation, and regulation of energy and momentum from the Sun to the upper atmosphere at high latitudes.

To achieve its science objectives, ASTRE will gather accurate measurements of plasma and neutral gases, electric and magnetic fields, and energetic particles using well-proven instruments with excellent flight heritage. ASTRE is a single, three-axis stabilized satellite that uses on-board propulsion to carry out systematic, low perigee excursions at high latitudes. The mission is highly synergistic with NASA and NSF funded programs that seek to understand not only ion-neutral coupling processes but also how magnetosphere sources of energy and momentum couple with the upper atmosphere. Deep dipping on Mars by similar instruments on the MAVEN satellite have revolutionized our understanding of the martian ionosphere-thermosphere system and we can expect equally ground-breaking results from ASTRE’s measurements within the Earth’s upper atmosphere.

This talk provides an overview of the scientific motivation and implementation plan of the ASTRE mission.