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Towards the world’s 6rst sample and return from an extra-terrestrial object , 1989ML, a near-Earth Asteroid, the Institute of Space and Astronautical Science (ISAS) of Japan has made an e<ort to make the technology develop and be ready for its scheduled launch in July 2002. It has four major purposes: carrying out (1) the use of ion engine as a primary means in the interplanetary 6eld propulsion, (2) an autonomous guidance and navigation scheme utilizing optical observations, (3) a robust and promising surface sample collection mechanics and (4) the direct reentry from an interplanetary trajectory for sample recovery on the ground. Through the 3 years of proto-type model phase distilling and brushing up the above-mentioned technologies, ISAS has 6nished making those ready to be actually realized in the 3ight model (FM) fabrication. The FM phase started from April 1999 and the fabrication of every component of the spacecraft was 6nished at the end of the year 2000, followed by the interface and 6tness check-out from January 2001. ISAS terminated its 6rst long-term operation test of its new type of an ion engine. It 6nished 18; 000 h of endurance test, which is the world’s incredibly long record that well meets the mission requirement. The engine makes use of the microwave excitation for the plasma generation excluding any electrode that has restricted the life of the conventional ion engines so far.
The grid made of the carbon–carbon composite has also contributed to lengthening the life. Another long-term test using the FM has started again this year for another con6rmation of its readiness towards the launch. The ablator material arc heating tests were completed in December 1998 at the NASA Ames Research Center, which indicated the good and suDcient performance of the heatshield developed by ISAS. ISAS conducts the DASH high-speed reentry demonstration 3ight the next year of 2001, by putting the small 90 kg payload (orbiter and capsule) to the H-IIA vehicle and placing it into the GTO trajectory. The DASH carries a similar reentry capsule that weighs 20 kg, which is decelerated and plunges into the atmosphere with the equivalent heat 3ux environment for showing the overall performance of the reentry capsule.
The paper summarizes not only the abovementioned four key technologies, but the spacecraft system and international collaboration structure as well. It also reports the termination of the development phase and describes its latest status and technologies readiness. The target object of the MUSES-C is 1989ML, a near-Earth asteroid. Its type is estimated as a black chondrite that is categorized into the safe object whose sample is not requested to be contained stringently. The spacecraft is scheduled to be launched in July 2002, arriving at the asteroid in October 2003. It stays around the asteroid for about 6 months and leaves in March 2004. The planned reentry of the capsule occurs in June 2006. The project is a joint NASA-ISAS endeavor and the capsule is assumed to be recovered in the Utah Training and Test
Range.
The MUSES-C spacecraft con6guration
