FIRSST: The Far-IR Spectroscopy Space Telescope

The Far-IR Spectroscopy Space Telescope (FIRSST) is designed to be a 2m-class, cryogenically cooled observatory as part of the NASA Astrophysics Probe Explore (APEX) program. FIRSST is intended to be primarily a guest-observer facility, with more than 90% of observing time dedicated to GO science. Equipped with both a multi-mode far-IR spectrometer (~30-300 μm) and a long-wavelength heterodyne array receiver (~200-600 μm), FIRSST will fill a critical gap in the range of wavelengths currently accessible to observers. Here, we present an overview of the current technical design, as well as highlighting the three key science themes identified by the science team.

1) What is the origin and evolution of planet-forming disks? FIRSST will precisely measure masses for the first statistical sample of protoplanetary disks using HD, as well as using a variety of other tracer species to understand gas dispersal via disk winds and help elucidate the origins of gas in debris disks.

2) What is the trail of water from molecular clouds to oceans? FIRSST will trace water through all stages of star and planet formation from star forming regions through to comets and other solar system bodies. FIRSST is specifically designed to enable direct measurements of the H/D ratio in water, providing a window into the origin of Earth's water, and the thermochemical conditions prevalent during the epoch of planet formation.

3) How do galaxies assemble their material? FIRSST will trace the production of metals, dust, and gas in galaxies along with their relation to star formation using broadband spectroscopy of fine structure lines (out to z~2) and silicate PAH features (out to z~5). We will also look at the coevolution of black holes and galaxies, investigate the impact of AGN outflows, and search for organic molecules in star forming regions.