  Segmented telescopes are a possibility to enable large-aperture space
telescopes for the direct imaging and spectroscopy of habitable worlds.
However, the complexity of their aperture geometry, due to the central
obstruction, support structures and segment gaps, makes high-contrast imaging
challenging. The High-contrast Imager for Complex Aperture Telescopes (HiCAT)
testbed was designed to study and develop solutions for such telescope pupils
using wavefront control and coronagraphic starlight suppression. The testbed
design has the flexibility to enable studies with increasing complexity for
telescope aperture geometries: off-axis telescopes, on-axis telescopes with
central obstruction and support structures - e.g. the Wide Field Infrared
Survey Telescope (WFIRST) - to on-axis segmented telescopes, including various
concepts for a Large UV, Optical, IR telescope (LUVOIR). In the past year,
HiCAT has made significant hardware and software updates to accelerate the
development of the project. In addition to completely overhauling the software
that runs the testbed, we have completed several hardware upgrades, including
the second and third deformable mirror, and the first custom Apodized Pupil
Lyot Coronagraph (APLC) optimized for the HiCAT aperture, which is similar to
one of the possible geometries considered for LUVOIR. The testbed also includes
several external metrology features for rapid replacement of parts, and in
particular the ability to test multiple apodizers readily, an active tip-tilt
control system to compensate for local vibration and air turbulence in the
enclosure. On the software and operations side, the software infrastructure
enables 24/7 automated experiments that include routine calibration tasks and
high-contrast experiments. We present an overview and status update of the
project, on the hardware and software side, and describe results obtained with
APLC WFC.
