  SPHEREx, the Spectro-Photometer for the History of the Universe, Epoch of
Reionization, and ices Explorer, is a NASA MIDEX mission planned for launch in
2024. SPHEREx will carry out the first all-sky spectral survey at wavelengths
between 0.75 micron and 5 micron with spectral resolving power ~40 between 0.75
and 3.8 micron and ~120 between 3.8 and 5 micron At the end of its two-year
mission, SPHEREx will provide 0.75-to-5 micron spectra of each 6.2"x6.2" pixel
on the sky - 14 billion spectra in all. This paper updates an earlier
description of SPHEREx presenting changes made during the mission's Preliminary
Design Phase, including a discussion of instrument integration and test and a
summary of the data processing, analysis, and distribution plans.
