Small Demonstration Satellite-4 (SDS-4): Development, Flight Results, and Lessons Learned in JAXA’s Microsatellite Project

Small Demonstration Satellite-4 (SDS-4): Development, Flight Results, and Lessons Learned in JAXA’s Microsatellite Project

The Small Demonstration Satellite 4 (SDS-4) is the first zero momentum three-axis controlled 50kg class satellite from JAXA. It was launched on May 17, 2012 on H-IIA Launch Vehicle, and is now operating successfully. SDS-4 has four main demonstration missions: (1) Space-based automatic identification system experiment for tracking ships, (2) Flat-plate heat pipe on-orbit experiment, (3) Quartz crystal Microbalance for contamination environment monitoring, and (4) In-flight experiment of space materials using THERME, which is developed in the JAXA-CNES joint research program. The satellite has two deployable solar panels to the left and to the right, and two deployable AIS antennas in the front and in the back. In addition to the technology demonstration missions, SDS-4 has another important goal, namely to establish a 50 kg-class highly functional and precise three-axis controlled standard bus for future advanced missions. After a year of on-orbit experiments and evaluations, all missions are now deemed successful and excellent flight data has been obtained. We encountered several serious problems during operations. We investigated the reasons for those misbehaviors in a multi-step process using a methodical FTA approach, and managed finally to resolve all of the problems. This paper concludes with the lessons learned all of which contributed to the overall success of the SDS-4 project.