TPF-C Technology Plan - Exoplanet Exploration Program - NASA

Recent Highlights
Technical progress against the previous development plan (Technology Plan for the Terrestrial
Planet Finder, March 2003) has been dramatic, particularly in the past year.
The critical technologies for TPF-C have been identified as those required for starlight
suppression in both narrow and broad bands. The primary testbed for demonstration in this area,
the High Contrast Imaging Testbed (HCIT), had achieved a contrast of 10 -5 by March of 2003.
As of December 2004, a contrast of 0.9 × 10 -9 , an improvement of better than 4 orders of
magnitude, had been achieved with laser light as shown in Figure i-1. Broadband experiments
have also begun during this interval, achieving a contrast of 5 × 10 -9 over a 40-nm bandpass.
These contrast values refer to an average contrast within the half-dark hole extending from 4 to
10 λ/D. These achievements represent significant progress against the milestones agreed upon
for entry into Phase A.
Figure i-1. Laboratory results from the HCIT showing an average contrast of 0.9 × 10 -9 for laser
light, as measured in the half dark hole (shown on a logarithmic scale in the upper-left corner)
over angles from 4 to 10 λ/D.
Progress in two component technologies was essential to achieving the performance the HCIT
demonstrated. The first was the fabrication of gray scale masks consistent with the 10 -9 contrast
achieved, and the second was continued development of the deformable mirrors (DMs).
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