Mars, Earth, or deep space? ESA narrows down finalists for a future space mission.

Mars, Earth, or deep space? ESA narrows down finalists for a future space mission.

The European Space Agency (ESA) has narrowed down proposals for a future medium-sized (M-class) mission. On November 8, 2023, the final three proposals were revealed to be:

• M-Matisse: A mission to study the interaction of the solar wind with the atmospheres of Mars and Earth.
• Plasma Observatory: A mission to study plasma physics in the Earth's magnetosphere.
• Theseus: A mission to study high-energy gamma-ray bursts from far beyond the solar system.
• The winning mission is expected to be launched in the mid-2030s.

All three proposals are ambitious and exciting, and they offer the potential to make significant advances in our understanding of space. M-Matisse would help us to better understand how the solar wind affects the atmospheres of Mars and Earth, which could have implications for our understanding of climate change on both planets. Plasma Observatory would provide new insights into the physics of plasma in the Earth's magnetosphere, which could help us to better understand how to protect satellites and astronauts from radiation damage. Theseus would study high-energy gamma-ray bursts, which are the most energetic explosions in the universe. Theseus would help us to better understand the physics of these explosions and their role in the evolution of the universe.

The ESA will now conduct further studies of the three proposals before making a final decision about which mission to select. The decision is expected to be made in 2025.

About the three finalists

M-Matisse would study the interaction of the solar wind with the atmospheres of Mars and Earth. The solar wind is a stream of charged particles that flows from the Sun. It can have a significant impact on the atmospheres of planets, and it is thought to play a role in climate change on Mars. M-Matisse would use a suite of instruments to measure the composition and dynamics of the solar wind and the atmospheres of Mars and Earth. The mission would also study the effects of the solar wind on the aurorae on both planets.

Plasma Observatory would study plasma physics in the Earth's magnetosphere. The magnetosphere is the region of space around the Earth that is dominated by the Earth's magnetic field. It is home to a variety of plasma phenomena, including the aurorae, the Van Allen belts, and the plasmapause. Plasma Observatory would use a suite of instruments to study the dynamics and composition of plasma in the magnetosphere. The mission would also study the interaction of the solar wind with the magnetosphere.

Theseus would study high-energy gamma-ray bursts from far beyond the solar system. Gamma-ray bursts are the most energetic explosions in the universe. They are thought to be caused by the collapse of massive stars or the merger of neutron stars. Theseus would use a suite of instruments to study the spectrum, polarization, and variability of gamma-ray bursts. The mission would also study the afterglows of gamma-ray bursts, which are the fading emission that remains after the initial burst of gamma rays.

All three of these missions are highly ambitious and offer the potential to make significant advances in our understanding of space. The ESA will now conduct further studies of the three proposals before making a final decision about which mission to select.