finish downloading from 
https://pds-geosciences.wustl.edu/mex/
continue at pfs
compare against
https://pds.nasa.gov/tools/dsstatus/dsidStatus.jsp?sortOpt1=di.dsid&sortOpt2=&sortOpt3=&sortOpt4=&sortOpt5=&nodename=GEOSCIENCE&col2=di.archivestat&col3=&col4=&col5=&Go=Submit+Query