A detta di un forum americano:
“Until recently, ISAS had been preparing another lunar mission, Lunar A, with penetrators to implant in the Moon’s surface. This mission was cancelled after problems emerged in the tests of the penetrators, but technology work on the concept continues with the hope of someday being able to consider the mission again.”
Ricordo che Lunar A sarebbe dovuta partire nel 1997 ma tutta una serie di problemi ne hanno rimandato il lancio fino ad oggi.