On the heels of the Psyche webinar, Space Science Reviews has a paper on that Gamma Ray/Neutron Spectrometer. In vol. 221:
Lawrence, D. J. Goldsten, J. O. Peplowski, P. N. et al. The Psyche Gamma-Ray and Neutron Spectrometer Art. 78 s11214-025-01201-6
There’s only so much you can do with a camera, I don’t care if it extends into silicon infrared. Plenty of elements (let alone minerals) simply don’t look like anything special. The Psyche mission also carries a magnetometer, but magnetic fields alone are a derived property, not a primary one, and may confound multiple possible sources. No, a chemical assay is called for here. A chemical assay implies either a sample return, a landed chemistry lab, or from orbit, a high-energy particle detector for certain elements. The Psyche GRNS is that detector, sorry, no sample return for the time being.
As befits a SpaceSciRev paper, the GRNS description is broad and deep. We get the science justification (as I mentioned above)- a different formation/history are implied if Psyche’s metal is alloyed with one side-element, versus another. The GRNS is also given spatial resolution, to spot any patchiness in the composition of Psyche. Upshot: GRNS meets or exceeds science requirements.
We then go through a rundown of the GRNS design, and a description of its ground calibration and in-flight checkout. As per the Psyche workshop, the instrument has been spending its cruise phase observing galactic cosmic rays and gamma-ray bursts. Truly, a science spacecraft.
In just a few years, the Psyche mission will be unraveling the secrets of this unique body- what we expect to be the (mostly) exposed core of a former planet(esimal). Depending on what GRNS tells us, we may learn of not just the asteroid’s core, but of all planet cores. Truly planetary science!