Press Releases


Miniature Ion Thruster Propulsion System, In-Flight Operation First operation of an ion thruster on a small satellite (less than 100 kg) : Associate professor Hiroyuki Koizumi & Professor Shinichi Nakasuka, Department of Aeronautics and Astronautics


The University of Tokyo and the Next generation Space system Technology Research Association (NESTRA) in Japan successfully completed initial operations of a miniature ion thruster propulsion system on board 50 kg nano-satellite “Hodoyoshi-4” on October 28, 2014; the world’s first operation of an ion thruster on a satellite smaller than 50 kg. The miniature ion propulsion system (MIPS, shown in Figures 1 and 2) was developed by the University of Tokyo and NESTRA. It was installed on 50 kg nano-satellite "Hodoyoshi-4," which was developed by NESTRA as a part of the Japanese government-funded “New Paradigms of Space Development and Utilization via Nano-satellites” project. The development of the MIPS began with an engineering model in 2011 and continued to a flight model in March 2014. The MIPS flight model has a wet mass of 8.1 kg (7.1 kg dry mass), a volume of 34 cm × 26 cm × 16 cm, power consumption of 27 W, thrust of 210 μN, and a specific impulse of 740 s (details are shown in Table 1). Hodoyoshi-4 was launched on June 20, 2014 and was positioned into a sun synchronous orbit at 600 km altitude. The project team has continued the mission, monitoring the sub-components of the propulsion system. On October 28, the team accomplished ion thruster operation and successful ion acceleration of six minutes, within the operating time of the satellites.


Hiroyuki Koizumi
Research Center for Advanced Science and Technology
The University of Tokyo


Reiko Satogata
Next generation Space system Technology Research Association



Table 1. MIPS-FM specifications


Hodoyoshi-4 Flight Model

High-Delta-V Model

Power consumption

27 W

34 W

Wet mass

8.1 kg

(including 0.9 kg Xe propellant)

8.6 kg

(including 0.9 kg Xe propellant)


34 cm × 26 cm × 16 cm

34 cm × 26 cm × 16 cm


210 μN

300 μN

Specific impulse

740 s

1100 s

Delta-V for the 50-kg satellite

140 m/s

320 m/s




Figure 1.           MIPS-FM (Miniature Ion Propulsion System)


MIPS-FM test


Figure 2.  MIPS-FM during a ground test at the University of Tokyo