SEEDS-II (Space Engineering Education Satellite II) is the successor of our first satellite SEEDS. SEEDS-II is also a CubeSat with 10cm cubic and 1kg in weight. The summary of SEEDS-II is shown in the table below. The official name is SEEDS-II, but we call it "SEEDS" because the launch of the first one was failed and it is our first satellite that reached in space.

Size, Mass10cm cube, 1kg
Project Kick offAughts 2006
FM completeJune 2007
Downlink (CW, FM): 437.485MHz
Uplink (FM); 140MHz band
MOU of launchAugst 2006 (University of Toronto, UTIAS SFL)
ExportJune 2007 (to UTIAS SFL)
Launch date9:23:51 April 28, 2008 (local time. 12:53:51 JST)
Launch vehiclePSLV-C9 (ISRO/Antrix, India)
Launch siteSatish Dawan Space Center
Launch configuration Cluster launch of 10 satellites (Primary satellite: CARTOSAT-2A (India). Piggy back: IMS (India), RUBIN8 (Germany), CanX-6 (Canada), CanX-2 (Canada), COMPASS-1 (Germany), Delfi-C3 (Nederland), AAUSAT-II (Denmark), Cute1.7+APD II (Japan, TokyoTech), and SEEDS II)
Satellite separation systemX-POD (UTIAS SFL)
Launch resultSuccess. Orbit: SSO, Inclination: 98.0 deg. Apogee: 636km, Perigee: 615km
Budgetbudget supplied by our university, and Grant by MEXT (Good Practice program)

SEEDS-II was developed on the basis of the design conept such that the subsystem FMR receiving the uplink command and performing the flight management manages the whole of the satellite system, which is the same as SEEDS. SEEDS-II is improved from SEEDS in the following points:

  1. Change of solar cells (from Si type to Gs type), and installation of shunt circuit to consume the surplus power caused by the improvement of the power generation efficiency.
  2. Change of the solar cell boards and the position of the data port caused by the change of solar cells
  3. Change of telemetry format of CW
  4. Expansion of function of characeter packet transmission (from 16 characters to 120 characters including Japanese characeter)
  5. Expansion of function of digi-talker (from english voice 60 seconds to english boice, SSTV signal, Japanese voice 120 seconds)
  6. Mount of micro film
We had recruited the messages for micro flims since October 2006 to November 2006 as an outreach campaign, which was reported by a newspaper and other media. We received 800 messages from 1500 people. Yachiyo Micro Film Service supported the manufacturing of micro films. We really appreciate their support.

The mission of SEEDS-II is the same as that of SEEDS:

Minimum MissionDownlink of housekeeping data by CW signal
Middle Mission Downlink of sensor data by FM packet (AX.25 protocol)
Attitude analysis using sensor data (gyro, geomagnetic sensor, and others)
Advanced Mission Downlik of voice by digi-talker
Downlink of analogue image by SSTV signal

Thie right photo is a slide show of the snapshot of developmen of SEEDS-II. The development period was only 10 months, but we passed the communication test of ground station and satellite station without the space communication. After we exported SEEDS-II to University of Toronto, we continued the development of the operation software, the analysis of the power consumption using EM, and got ready for launch. The call sign of the ground station and satellite station is as follows:


SEEDS-II was exported to India in March 2008, 9 months after the export to Toronto. We conducted the flight operation at Satish Dawan Space Center before the launch. After that, SEEDS-II and other satellites were put on the PSLV rocket and launched in April 28, 2008. The launch was successful and the member of Satellite Lab have been oerating SEEDS now.

The below figures illustrates the ground station software (for tracking, downlink, uplink, and database), an example of SSTV image downlinked by amateur radio person ((DK3WN Mike san in Germany), and the analysis results of the downlink data.

SEEDS-II is used for outreach now. We hope you get the voice and SSTV signal from SEEDS-II!.

[1] 椋本佳宏,荒木友太,有田公輔,山崎政彦,長船隼祐,片山範将,宮崎康行,「SEEDS打ち上げおよび運用について」,第52回宇宙科学技術連合講演会CD-ROM講演集,2C07,pp.1051-1056,2008年11月5日−11月7日,淡路島.
[2] 山崎政彦,荒木友太,有田公輔,増田敬史,宮崎康行,松原一雄,中村義隆,「超小型人工衛星SEEDSおよびSPROUTの開発」,第51回宇宙科学技術連合講演会CD-ROM論文集,1B14,pp.1-6,2007年10月,札幌.

College of Science and Technology, Nihon University
Department of Aerospace Engineering
Space Structure Systems Laboratory
College of Science and Technology, Nihon University
7-24-1 Narashinodai, Funabashi, Chiba 274-8501, Japan
e-mail: asel (at) forth.aero.cst.nihon-u.ac.jp