SMILES-2 Mission for Temperature, Wind, and Composition in the Whole Atmosphere

The Superconducting Submillimeter-Wave Limb-Emission Sounder 2 (SMILES-2) is a satellite mission that will be proposed to the Japan Aerospace Exploration Agency (JAXA) for a launch after 2023. It will scan the atmospheric limb from the lower stratosphere to the lower thermosphere for retrieving the profiles of temperature between 15 and 160 km, horizontal wind vector (30-160 km), ground state atomic oxygen (90-160 km), and dynamical tracers and ozone-chemistry related species (15-110 km). SMILES-2 is designed to fit the JAXA small satellite and will be equipped with two antennas, three GHz-channel receivers, and one THz receiver. Each receiver has a superconducting device on the front end cooled by a mechanical cryocooler, which is an established technology. Highly sensitive limb observation owing to the superconducting technology has great advantages of satisfactorily measuring all the altitude profiles in a short time of less than 1 min, and of retrieving the main products with sufficient precision on a single profile. Hence, a wind vector profile can be obtained with a precision better than 10 m s−1 with a vertical resolution of 3 km below 100 km and 5 km above 100 km.