Pale Blue Dot Explorer: A Case for Adding Earth to the Planetary Sciences List of Targets

Obtaining observational data to inform the science of future missions focused on
Earth-like exoplanets is of prime importance for NASA Planetary Science and
Astrobiology. However, Earth observations as a proxy for an exoplanet is an area of
interdivisional research not well captured by existing NASA programs. To accommodate
this, we propose adding Earth to the list of planets allowable by NASA Planetary
Science Division’s objectives and adding Earth observation to the cruise phase of
planetary probes. A specific research investigation would be a spacecraft whose goal
would be to characterize Earth as an exoplanet proxy — a Pale Blue Dot Explorer. Such
a mission’s objective would be to monitor the habitability and biological signatures of
Earth in reflected light over broad wavelengths and phase angles.