The atmospheric characterization of a significant number of terrestrial planets, including the search for habitable and potentially inhabited planets, is probably the major goal of exoplanetary science and one of the most challenging endeavours in 21st century astrophysics.
However, despite being at the top of the agenda of all major space agencies and ground-based observatories, none of the currently planned projects or missions worldwide – neither in Europe, nor in the US, China or India – has the technical capabilities to achieve this goal.
LIFE addresses this issue by investigating the scientific potential and technological challenges of an ambitious mission employing a formation-flying nulling interferometer in space working at mid-infrared wavelengths. As such, LIFE is grounded in the heritage of ESA’s Darwin and NASA’s TPF-I concepts from the early/mid 2000s. However, breakthroughs in our understanding of the exoplanet population as well as significant progress in relevant technologies justify the need, but also the feasibility for a future mission like LIFE to investigate one of the most fundamental questions of humankind:
Are we alone in the Universe?
After an official kick-off in 2018 and community building efforts in 2020, LIFE is currently in a first study phase. Main activities include:
While LIFE can address a variety of fundamental questions in modern astrophysics, its design and implementation shall be driven by the following (preliminary) Science Objectives:
LIFE shall obtain thermal emission spectra with sufficient spectral resolution, wavelength coverage and sensitivity to investigate at least 30 (requirement) / 50 (goal) extrasolar planets with radii between 0.5 and 1.5 Earth radii and receiving between 0.35 and 1.7 times the insolation of the Earth in order to assess their habitability and search for biomarkers. The sample shall be roughly equally split between planets orbiting late K to early M-type stars and planets orbiting late F to early K-type stars.
Exoplanet science is omnipresent on the roadmaps of all major space agencies and ground-based observatories, and continues to drive the research activities of an increasing number of scientists worldwide. One of the long-term objectives is the investigation of the atmospheric properties of a statistically significant number (>100) of terrestrial exoplanets. The key motivations are to:
Key steps towards achieving these objectives will be possible in the coming 10-15 years with upcoming missions such as JWST, PLATO, WFIRST or ARIEL. However, none will provide the statistical dataset of terrestrial exoplanets that is ultimately needed. Given the precision and sensitivity requirements, a space mission seems inevitable for achieving the science goals. NASA is pursuing the idea of a large, single aperture UV/optical/near-infrared telescope (the HabEX and LUVOIR concepts). LIFE follows a complementary approach and focuses on the scientific prospects and the technical challenges of a space-based mid-infrared nulling interferometer. Concrete design studies are expected for the next project phases.