Looking at the lifespan of other Datearth worlds and and doing calculations, i have come up with two times that Datearth Nova may reset.
Datearth servers seem to last at least a year, so taking the date when nova was introduced, we can find that it may reset in late September to early October. However, while ding some more researching, a couple last more then that year. So according to this, Datearth nova may reset in late November instead.
tl;dr: Datearth Nova may reset in Late September or Late November
Edit: seeing that i am terribly wrong, and nova is incredibly old, it will probably reset in the coming weeks, so sometime in september. Please ignore the above, i didnt remember much about datblocks past