The reaction wheels (RW) are foreign-made.
Due to the "No reverse-engineering" conditions attached, they were unable to examine the cause of the breakdown.
Because foreign-made RW's are considerably cheaper than domestic ones, they were purchased instead due to budgetary concerns.
Still, these RW's were subjected to special processing; ironically, it's said that it was this special processing that caused the failure.
Daichi was scheduled to launch in 2006.
She would embark with the same company's RW's (although a different type).
Akatsuki, who was scheduled to launch in 2010, would be using the same RW's as Hayabusa.
The failure of Hayabusa's RW's has been leveraged to fix any errors.
There are 2 systems, for a total of 12 gas jets.
They don't allow for the same precise attitude control as a RW, but they're all that's available now. They are what is used now along with the remaining RW in order to perform attitude control. It's like going from using your hands (RW) with your keyboard, to using your feet (thrusters). (That's mostly correct)
MV5 seems pretty lively.
Of course, examining that way is out of the question.
Similar items would be pulverized instantly.
In actuality, the testing had been thoroughly simulated beforehand.
They could not waste the the fuel in special training.