SOTA
Overview
SOTA or Small Optical TrAnsponder is a JAXA research project carried aboard the SOCRATES satellite that was launched in 2014. Its primary purpose was communications tests with NICT ground stations located in Okinawa and Kashima Japan, CNES Stations in Montreal Canada, ESA Stations in Tenerife Spain, and Cussol France, and DLR Stations in Oberpfaffenhofen Germany. It marked the first communications tests between a micro-satellite and a ground station. SOTA achieved a data rate of 10-Mbit/s downlight on two wavelengths and apertures, as well as reducing weight by ~134kg from the previous OICETS terminal to 5.9 kg. Two lasers are carried-a lower divergence, larger aperture and fine pointing and lower power Tx4 and a less precise but higher power Tx1. Tests began after the launch of SOCRATES and continued until November 2016. In addition to validating the transmission ability of the SOTA system to an OGS, additional experiments with international OGS and site diversity as part of the INNOVA program were conducted. Currently, LEO CubeSats can achieve data rates in the order of tens of Mbps, however, laser rates in the order of Gbps should soon be achievable. Another component of the SOTA mission was the testing of QKD communication. This marked the first successful demonstration of space-based quantum communication. [1]
Related Links
Paper: LEO-to-ground optical communications using SOTA
Paper: First Free Space Optical Communication in Europe Between SOTA and MeO Optical Ground Station
Paper: Laser communication experiments between SOTA and MeO optical ground station