The Neutron star Interior Composition ExploreR ( NICER ) is expected to launch in early 2017 and will gather X-ray data on neutron stars and other high-energy sources from a berth on the International Space Station .
Its prime scientific goal is to measure the masses and radii of non-accreting neutron stars via fits to the energy-dependent waveforms produced by the rotation of hot spots on their surfaces .
These measurements will provide valuable input to theoretical models of cold matter beyond nuclear density .
Here we propose that PSR J1614 - 2230 , despite its low count rate , is a promising source to observe with NICER .
The reason is that XMM-Newton observations suggest that the fractional oscillation amplitude from PSR J1614 - 2230 could be high enough that this star can not be very compact .
We show that if we analyze 0.5 Ms of NICER data and 0.1 Ms of nearby off-source data and combine that analysis with the known mass of this star , we would find a robust lower limit to the radius with a statistical uncertainty of only \sim 0.5 - 0.7 km .
We also show that even if there is an unmodeled nonthermal component modulated at the pulsation frequency , good statistical fits could rule out significant biases .
The low count rate will make reliable upper limits on the radius difficult , but the lower limit could rule out some equations of state that are currently being discussed .
This analysis would require a good estimate of the non-source background , so Chandra observations of the vicinity of PSR J1614 - 2230 would be helpful .