  Many protocols in quantum science and technology require initializing a
system in a pure quantum state. In the context of the motional state of massive
resonators, this enables studying fundamental physics at the elusive
quantum-classical transition, and measuring force and acceleration with
enhanced sensitivity. Laser cooling has been a method of choice to prepare
mechanical resonators in the quantum ground state, one of the simplest pure
states. However, in order to overcome the heating and decoherence by the
thermal bath, this usually has to be combined with cryogenic cooling. Here, we
laser-cool an ultracoherent, soft-clamped mechanical resonator close to the
quantum ground state directly from room temperature. To this end, we implement
the versatile membrane-in-the-middle setup with one fiber mirror and one
phononic crystal mirror, which reaches a quantum cooperativity close to unity
already at room temperature. We furthermore introduce a powerful combination of
coherent and measurement-based quantum control techniques, which allows us to
mitigate thermal intermodulation noise. The lowest occupancy we reach is 30
phonons, limited by measurement imprecision. Doing away with the necessity for
cryogenic cooling should further facilitate the spread of optomechanical
quantum technologies.
