Electric propulsion with a high-specific impulse for satellite applications allows earth-orbiting satellites to perform versatile and complex operations. When used as the final-stage motor of transportation systems, it is a key technology to pioneer deep space explorations. R&D continues on a pulse-plasma thruster (PPT) and DC arc jet. An MPD arc jet was demonstrated on SFU while a microwave discharge-type ion engine was proven as the main propulsion of the asteroid explorer HAYABUSA

As a future interplanetary propulsion system, research focuses on demonstrating the engineering feasibility of non-nuclear outerplanetary explorations. As a means of future interplanetary flight, the solar electric sail to drive ion engines with high specific impulse is attracting attention recently as a highly probable solution. The feasibility of the solar electric sail has been promoted by the advent of lightweight and extremely thin film technology. JAXA launched a Small Solar Power Sail Demonstrator "IKAROS" for technological verification.

For detailed and wide-ranged exploration over lunar or planetary surface, research continues into rover systems such as: running mechanisms; autonomous functions; terrain mapping; route planning; barrier detection/avoidance; intellectual remote manipulation; and telescience technologies. R&D also continues into small and lightweight sampling manipulators for surface exploration, excavation robots for planetary interior exploration, and hopping robots for autonomous exploration in a microgravity environment.

The many tasks for a reusable space transportation system include: improvement of engine performance; development of technology to minimize the vehicle's weight; and creation of a system to guarantee the safety of repeated multiple flights. To facilitate the next full-scale development, ISAS is conducting element-technology research targeting innovative future space transportation as well as demonstrating the new technologies through actual flights of the test vehicle.