  The remarkable optical properties of the solar gravitational lens (SGL)
include major brightness amplification (~1e11 at wavelength of 1 um) and
extreme angular resolution (~1e-10 arcsec) in a narrow field of view. A mission
to the SGL carrying a modest telescope and coronagraph opens up a possibility
for direct megapixel imaging and high-resolution spectroscopy of a habitable
Earth-like exoplanet at a distance of up to 100 light years. The entire image
of such a planet is compressed by the SGL into a region with a diameter of ~1.3
km in the vicinity of the focal line. The telescope, acting as a single pixel
detector while traversing this region, can build an image of the exoplanet with
kilometer-scale resolution of its surface, enough to see its surface features
and signs of habitability. We report here on the results of our initial study
of a mission to the deep outer regions of our solar system, with the primary
mission objective of conducting direct megapixel high-resolution imaging and
spectroscopy of a potentially habitable exoplanet by exploiting the remarkable
optical properties of the SGL. Our main goal was to investigate what it takes
to operate spacecraft at such enormous distances with the needed precision.
Specifically, we studied i) how a space mission to the focal region of the SGL
may be used to obtain high-resolution direct imaging and spectroscopy of an
exoplanet by detecting, tracking, and studying the Einstein ring around the
Sun, and ii) how such information could be used to detect signs of life on
another planet. Our results indicate that a mission to the SGL with an
objective of direct imaging and spectroscopy of a distant exoplanet is
challenging, but possible. We composed a list of recommendations on the mission
architectures with risk and return tradeoffs and discuss an enabling technology
development program.
