NICER observation list: Target ID 555701

The ultracompact white dwarf systems HM Cnc and V407 Vul represent unique opportunities to probe binary evolution driven by gravitational radiation and mass transfer. NICER observations to date have provided new, precise frequency measurements in both systems, and the first measurement of an orbital frequency second derivative in an ultracompact binary. We propose observations of both sources to continue to extend their temporal baselines, enabling new, unique probes of their orbital evolution.