What are the minimum freesurfer output files required for fmriprep?

i need to preprocess the HCP-Aging dataset using fMRIprep, i see that the freesurfer output files are available for download from the NIMH data archive. In the interest of conserving disk space (not much disk space on my HPC cluster), may i know if i can skip the downloading of any of the freesurfer output subdirectories or files?