NASA's Mission Page Deep Space Optical Communications (DSOC) includes the following:
Key DSOC technologies developed for the project include: a low-mass spacecraft disturbance isolation and pointing assembly; a high-efficiency flight laser transmitter; and a pair of high-efficiency photon counting detector arrays for the flight optical transceiver and the ground-based receiver. These technologies are integrated into the DSOC flight laser transmitter and ground-based receiver to enable photon-efficient communications with the capability to discern faint laser signals from background "noise" contributed by solar energy scattered by the Earth's atmosphere.
Two previous questions and their answer highlight that for conventional optical communications schemes based on photodiode conversion of modulated optical intensity to likewise-modulated electrical signals the achievable data rate scales as (surprisingly) $1/r^4$ rather than the familiar $1/r^2$ for conventional deep-space radio communications systems.
It is possible that an optical system based on photon counting will have a more favorable scaling of data rate versus distance than $1/r^4$ so I'd like to ask:
Question: How is the maximum data rate of the Psyche mission's Deep Space Optical Communications (DSOC) system expected to scale with distance?
- Receiver and transmitter in RF/optic satellite communication: distance vs data rate v2
- this answer to Quantitatively, why will optical communication be better than X-band for deep-space communications?
- Are direct conversion optical receivers being looked at for future deep-space communication?
From SPIE.org's news item Optical communications work best over relatively short distances in space (06 April 2006 Morio Toyoshima, Walter Leeb, Hiroo Kunimori, and Tadashi Takano)
Figure 1. Maximum data rates for optical and RF communication systems versus link distance. GEO stands for geostationary earth orbit, and arrows show distances to GEO, Moon, and Mars.