Technology: System Overview | Spacecraft | Earth Stations

Technology

Earth Stations

Link Evaluation Terminal (LET)

Photo of Link Evaluation Teminals (LET) The LET is located at Glenn Research Center’s NASA Ground Station (NGS) for ACTS. It is a flexible Ka-band RF terminal that can be adapted to support various modulation and digital formats to communicate with ACTS in the bent-pipe or MSM mode of operation. It operates as a hub station or as an independent experimenter terminal. The LET has supported a number of experiments where the experimenter equipped the terminal with compatible receiving and/or transmitting electronics so it would function as a second terminal in an experiment. It was cross-strapped to the NASA Ground Station to act as back-up terminal to the NGS for commanding the spacecraft. The High Data Rate Terminal digital electronics were also interfaced to the RF terminal of the LET so that it could perform as a node in a High Data Rate Terminal network.

Antenna Diameter: 4.7 meters. Amplifier: 10 to 60 watts (variable). Uplink/Downlink Burst Rates: 220 Mbps nominal; variable depending on experimenter’s electronics. Throughput: Up to 622 Mbps depending on experimenter’s electronics.

Maxiumum EIRP: 68-76 dBW. Nominal G/T: 27 dB/K.