The Geodetic Autonomous Inter-Spacecraft Network (GAIN) program, which builds on the successes of two NASA-sponsored programs, has produced a miniaturized, flexible, and autonomous interspacecraft communications and ranging system that meets the constraints of mass, size, power, cost, simplicity, flexibility, and autonomy demanded by distributed systems of small spacecraft. GAIN’s operational concept for communications and ranging was developed and validated under NASA Goddard Space Flight Center’s Magnetospheric Multi-Scale Mission, Inter-Satellite Ranging and Alarm System program. GAIN’s transmitter and receiver designs are based on those developed under NASA’s University-class Explorer (UNEX) program for the Cooperative Astrophysics and Technology Satellite (CATSAT).
GAIN electronics box (communications and ranging electronics, transmitter, and receiver).
Two GAIN radios were developed and demonstrated, and were delivered (in 2006) to the NASA Glenn Research Center. Each radio consists of a laptop computer and an electronics box. The computer functions as the user interface and as the main processing unit. The electronics box consists of three boards: the communications and ranging board, the transmitter board, and the receiver board. These boards are 164 cm2 each, with a total combined weight of 1429 g (including the enclosure).
The GAIN system enables packet-based communications between members of a satellite constellation at data rates of 125 bps, 1 kbps, 8 kbps, or 32 kbps. The operating frequency is S-Band (2039.65 MHz). In addition, the GAIN system enables range measurements between all spacecraft pairs in the constellation with an accuracy of 1 percent (or better) for distances of 100 to 6400 km and with an accuracy of 1 km (or better) for distances from 10 to 100 km. Extensive testing in both wired and wireless configurations verified proper operation of the radios.
The GAIN radios can be upgraded or modified easily since much of the functionality is defined in software residing on the laptop computer. One example is the application of the GAIN radios to a robotics demonstration. For this demonstration, Glenn personnel were able to quickly expand the radio capabilities to provide an integrated command and ranging channel. The GAIN program was executed by SpaceWorks, Inc., under NASA contract NAS3-03090.
Testing of GAIN radios (wired configuration).
Last updated: December 17, 2007
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