This is my take on how Power Rangers in Space should have been done:
The Power Rangers have finally defeated Rita, but unfortunately, the victory is short lived as Lord Zed strikes and strikes hard. He
destroys the comand center, along with the Rangers Powers. To add insult to injury, Lord Zed captures Zordon and heads to space.
The Rangers have no choice but to go after him, but leave Tommy behind to protect the earth just in case they fail. Armed with the experimental powers left in the rubble of the Command Center, the rangers make their way into space to rescue Zordon, and save the Earth.