A key challenge for starshades is formation flying. To successfully image exoplanets, the telescope boresight and starshade must be aligned to ∼1  m at separations of tens of thousands of kilometers. This challenge has two parts: first, the relative position of the starshade with respect to the telescope must be sensed; second, sensor measurements must be combined with a control law to keep the two spacecraft aligned in the presence of gravitational and other disturbances. In this work, we present an optical sensing approach using a pupil imaging camera in a 2.4-m telescope that can measure the relative spacecraft bearing to a few centimeters in 1 s, much faster than any relevant dynamical disturbances. A companion paper will describe how this sensor can be combined with a control law to keep the two spacecraft aligned with minimal interruptions to science observations.

Directly imaging and characterizing Earth-like exoplanets is a tremendously difficult instrumental challenge. Present coronagraphic systems have yet to achieve the required 10^−  10 broadband contrast in a laboratory environment, but promising progress toward this goal continues. An approach to starlight suppression is the use of a single-mode fiber (SMF) behind a coronagraph. By using deformable mirrors to create a mismatch between incoming starlight and the fiber mode, SMF can be turned into an integral part of the starlight suppression system. We present simulation results of a system with five SMFs coupled to shaped pupil and vortex coronagraphs. We investigate the properties of the system, including its spectral bandwidth, throughput, and sensitivity to low-order aberrations. We also compare the performance of the SMF configuration with conventional imaging and multiobject modes, finding improved spectral bandwidth, raw contrast, background-limited signal-to-noise ratio, and demonstrate a wavefront control algorithm, which is robust to tip/tilt errors.

• Case 1: Starshade with a 1.1m dedicated telescope prioritizing the search for earths in the Habitable Zone (HZ).

• Case 2: Starshade with a 1.1m dedicated telescope focused on maximizing planet harvest return and characterization.

• Case 3: Starshade that rendezvous with a 2.4 m shared telescope prioritizing the search for earths in the HZ.

• Case 4: A Rendezvous Earth Finder mission based on a 40-m diameter starshade with a 2.4 m telescope, operating for 4 years, and focused exclusively on detecting Earths in the HZ