SDS-4 (Small Demonstration Satellite 4) is a small satellite (50cm cube with mass of 50kg) developed by JAXA. It was launched as a secondary payload on the Shizuku mission on 17 May 2012 UTC.
In 2019, its ownership was transferred to the SKY Perfect JSAT Corporation (JSAT). Operation was terminated by the end of June 2021.
There are four rather specialised systems on the satellite:
SPAISE (SPace-based Automatic Identification SystEm) - test on-orbit a receiver for picking up signals from Automatic Identification System transmitters on ships well out to sea, and determine how space-based reception is affected by interference between nearby transmitters and by environmental conditions.
FOX (Flat heat-pipe on-orbit experiment) - to test whether flat heat pipes work in space in accordance with theoretical models and with tests on Earth
IST (In-flight experiment of Solar absorption rate with THERME) - to acquire information about the effect of sunlight in space on thermal coatings, re-flying the THERME instrument developed by CNES for testing different thermal coatings
QCM (Quartz Crystal Microbalance) - to test whether a Japanese-manufactured quartz microbalance works well in monitoring contamination of the satellite from assembly to on-orbit operation.
References
↑Krebs, Gunter. "SDS 4". Gunter's Space Page. Retrieved 31 October 2013.
↑McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 31 October 2013.
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
