Princeton University Gravity Initiative Spring Seminar Series

This year, NASA is beginning its search for a Probe-class ($1B) mission to fly in ~2032. This once-per-decade opportunity was endorsed by astro2020 as a way to achieve some of the science promised by the more complex and expensive far-infrared and X-ray missions that were prepared for the decadal survey. SALTUS, latin for leap, is a far-infrared Probe proposal that is built around a 20-meter passively cooled inflatable aperture. The collecting area of such a telescope, approximately 10x that of JWST while operating at a similar temperature, will allow dramatic advances in many areas of science and provide important pointed followup for surveys that will proceed through the coming decade. SALTUS will be instrumented with mid- and far-IR spectrometers (4-300 um), THz heterodyne receivers, and a multi-frequency receiver for very-long baseline interferometry (VLBI) observations with telescopes on the ground. I will describe the mission concept and some key scientific goals in the areas of exoplanets and planet formation, the assembly of the first galaxies and the buildup of dust and metals, and the physics of black holes. I will give particular attention to the case for the VLBI instrument, which will extend EHT-like millimeter VLBI observing to microarcsecond resolution to test General Relativity, measure black hole masses, and explore the physics of accretion and jet formation.