When does Elliott from Earth return?

Elliott from Earth is a British animated television series. The show follows an 11-year-old boy named Elliott and his mother Frankie who travel around Earth to study 65-million-year old rock meteorites. After discovering one of them with no fusion crust, one day accidentally powering it up, revealing it to be alien technology. Transporting them to another side of the Universe, they ended on a large space station called the Centrium. The three of them investigate their new environment and meet its alien inhabitants, eventually making their way into the city on the station where they find a new home for themselves.
Elliott and his mother Frankie travel around looking for meteorites on Earth to further study a 65-million-year-old rock which appears to be from space but lacks a fusion crust. One night, the two accidentally power up the rock, revealing it to be alien technology that can turn into a transport sphere and launch into space. The sphere transports them to another side of the Universe, where they end up on a large space station called the Centrium.