PY4 1, 2, 3, 4

PY4 [NASA]

PY4 () is a small constellation of four 1.5U Cubesat nanosatellites developed by NASA Ames Research Center.

PY4 is a low-cost, rapid-turn-around, four-satellite technology demonstration based on the open-source PyCubed avionics framework. PyCubed is an opensource, radiation-tested CubeSat avionics platform that integrates power, computing, communication, and attitude determination and control functionality into a single low-cost module programmable entirely in the programming language Python.

The goal of PY4 is to demonstrate low size, weight, power, and cost (SWaP-C) spacecraft-to-spacecraft ranging, on-orbit relative navigation, and coordinated simultaneous multi-point radiation measurements. By developing and demonstrating these technologies on a small scale, they can be implemented for future multi-spacecraft missions, enabling NASA to pursue its future science, technology, and exploration goals.

The four identical PY4 spacecraft periodically measure their relative distances to an accuracy of 1 meter or better by measuring the time-of-flight of radio packets exchanged between all spacecraft. These range measurements provide information about the relative positions of the spacecraft which, when combined with other sensor data, can be used to uniquely determine the configuration of the swarm. This on-board determination of the swarm’s topology is achieved through use of low-cost commercial offthe-shelf transceivers leveraged from the prior NASA Small Spacecraft Technology program mission, V-R3x, that launched to low-Earth orbit on 24 January 2021.