Atmospheric turbulence compensation via adaptive optics (AO) will be essential for achieving most objectives of the
TMT science case. The performance requirements for the initial implementation of the observatory's facility AO system
include diffraction-limited performance in the near IR with 50 per cent sky coverage at the galactic pole. This capability
will be achieved via an order 60x60 multi-conjugate AO system (NFIRAOS) with two deformable mirrors optically
conjugate to ranges of 0 and 12 km, six high-order wavefront sensors observing laser guide stars in the mesospheric
sodium layer, and up to three low-order, IR, natural guide star wavefront sensors located within each client instrument.
The associated laser guide star facility (LGSF) will consist of 3 50W class, solid state, sum frequency lasers,
conventional beam transport optics, and a launch telescope located behind the TMT secondary mirror.
In this paper, we report on the progress made in designing, modeling, and validating these systems and their components
over the last two years. This includes work on the overall layout and detailed opto-mechanical designs of NFIRAOS and
the LGSF; reliable wavefront sensing methods for use with elongated and time-varying sodium laser guide stars;
developing and validating a robust tip/tilt control architecture and its components; computationally efficient algorithms
for very high order wavefront control; detailed AO system modeling and performance optimization incorporating all of
these effects; and a range of supporting lab/field tests and component prototyping activities at TMT partners. Further
details may be found in the additional papers on each of the above topics.