 Fan acceptance of these comics got off to a shaky start when Marvel's inaugural publication of its new "Star Trek" line turned out to be a crossover between TOS and Marvel's popular superhero team, the X-Men.This was followed by an X-Men/TNG crossover and a Pocket Books novel, "Planet X," which was also based on this premise.The different series turned out popular, with "Starfleet Academy" and "Early Voyages" registering strong sales.