"Son Goten, do you mean you want to go to Planet Namek to find the Dragon Balls and bring Yamcha back to life?" They definitely had to go to Planet Namek. After all, Frieza would arrive there in two months.
If they didn't stop him from getting the Dragon Balls beforehand, and Frieza managed to fulfill his wish for eternal life, then even if Son Goten became a Super Saiyan, he still might not be a match for him.
After all, the difference in strength between a Super Saiyan and Frieza wasn't that great, and Frieza was immortal. Fighting him would only end with them being worn down to death!
So Son Goten planned to head to Planet Namek before Frieza arrived. It would also be a great opportunity to ask the Grand Elder to draw out their Combat Power. If they still had time, they could bring Yamcha back to life, too.
"Frieza?" everyone asked. "What's Frieza?" Son Goten explained, "Well, uh, you'll more or less find out once you get to Planet Namek."
Son Goten couldn't tell them about Frieza, so he could only use Piccolo as a diversion. "You can also visit Piccolo's homeworld while you're there."
"Son Goten, are you really planning to go to Planet Namek? Even with the spaceship my dad just finished developing, I'm afraid it won't be able to leave the solar system," Bulma said worriedly.
It was true that Earth's current level of technology wasn't enough for interstellar travel. But there was no need to worry about that. Nappa, the Saiyan, was dead, but his spaceship was still around.
"And when the old Kami came to Earth, he must have arrived in a spaceship, too. We can take it to your dad and have him modify it. Interstellar travel shouldn't be