Amendment 38: This amendment releases final text for program element D.10 NuSTAR Guest Observer – Cycle 4.

The Nuclear Spectroscopic Telescope Array (NuSTAR) Small Explorer (SMEX) mission is the first orbiting telescope to focus light in the high energy X-ray region of the electromagnetic spectrum (E > 10 keV), with an effective bandpass of 3–79 keV. The observatory provides a combined improvement in sensitivity and spatial/spectral resolution by factors of 10 to 100 over previous missions that have operated at these energies. The NuSTAR Guest Observer (GO) Program solicits proposals for basic research relevant to the NuSTAR mission.

The Phase-1 proposal due date for D.10 NuSTAR Guest Observer – Cycle 4 is January 19, 2018. Phase-1 proposals may be submitted via http://heasarc.gsfc.nasa.gov/ark/nustar/ (Help Desk available at http://heasarc.gsfc.nasa.gov/ark/rps/help/)

Technical questions concerning this program element may be directed to Craig Markwardt at Craig.Markwardt@nasa.gov.

Programmatic information may be obtained from Stefan Immler at Stefan.Immler@nasa.gov.