|Mission type||Technology demonstrator|
|Website||Official page (Japanese)|
|Manufacturer||Advanced Engineering Services Co., Ltd.|
|Launch mass||48 kg (106 lb)|
|Dimensions||496 mm × 495 mm × 485 mm (19.5 in × 19.5 in × 19.1 in)|
|Start of mission|
|Launch date||24 May 2014|
|Launch site||Tanegashima, LA-Y|
|Perigee altitude||629.8 km|
|Apogee altitude||647.4 km|
SOCRATES or Space Optical Communications Research Advanced Technology Satellite is a Japanese micro-satellite launched in 2014. The satellite is purely a technology demonstrator designed by NICT intended to help AES company to gain experience in basic mission control, attitude control and spacecraft communications. Its main experiment is SOTA (Small Optical TrAnsponder), an optical small satellite communications demonstrator. All subsystems of spacecraft are powered by solar cells mounted on spacecraft body and stub wings, with estimated electrical power of 120W BOL degrading to 100W EOL.
SOTA was the first lasercom onboard a microsatellite, performing a variety of experiments in a less-than-6 kg compact package, being the main one the 10 Mbit/s links at 1549 nm using coarse and fine-pointing to accurately transmit the 35-mW laser through a 5-cm Cassegrain telescope. SOTA had other additional capabilities, i.e. B92-like QKD protocol at 800-nm band to perform the first-time quantum-limited demonstration from space.