In Response to: Life Among the Stars

Excellent presentation. Two questions: Evidently the geometry of the starshade’s “petals” is critical to minimizing diffraction. What happens if one of the petals is hit by a micrometeorite, creating a tiny pinhole? Also, how is the orientation/rotation of the “occulter” (viz. the second spacecraft that blocks the starlight) maintained with respect to the telescope?

Editor’s note: Professor N. Jeremy Kasdin ’85 offers this response: Multiple layers of insulation should prevent a light path for a typical micrometeorite strike, and the effect of a small number of chips along the edge is within our error budget. The occulter will spin about its axis. By spinning, certain localized errors are averaged and thus easily differentiated from planets. Attitude control is similar to any conventional satellite; performance is very insensitive to errors in the angle of the starshade relative to the line of sight to the star.

Francis Jacobs *66