The Antarctic Plateau provides thebest terrestrial astronomical observing conditions across the Mid-InfraRed (MIR) and submillimeter wavebands due to its remarkable atmospheric transparency and stability. The opening of Concordia Station at Dome C is now offering a unique opportunity to the international submm astronomical community to perform ground-breaking astronomical science.To take advantage of these unique conditions, we are proposing the realization of an international Antarctic Submillimeter Observatory (ASO) based on the ALMA antenna prototype, to carry out both continuum and spectral line observations, across the MIR and submm wavebands. The telescope would be able to operate in the MIR using the innermost surface (2-4 m in diameter) of the primary reflector, which would be accurate enough to operateat wavelengths as short as ~5 micron.