How to load explorer onto a rocket ?

[maLENstwo]

How to load explorer onto a rocket ?

[Tiberius]

I am assuming you mean loading an explorer onto a rocket on mars that you will be sending back to earth? If so, I don't think you can. If you don't need it anymore, scrap it and collect the resources.

If you mean load an explorer on a cargo rocket to come to mars, then just hit the "+" sign beside the rc explorer to add one or more to the rocket then hit launch. Not sure which you meant so I tried to cover both.

[SkiRich]

I assume you mean for an expedition. You dont need to load anything. They happen automatically once you select the rocket to go out.
On the planetary screen, once you click on the anomoly and click send expedition, if you have more than one rocket landed, then select the rocket on the left side and cllick send again.
There will be an icon hovering over the rocket. That means its preparing to go.
It will auto select the crew and equipment, and take off on its own. You dont have a choice of what it takes. It ususally goes for the closest ones though. Reminder, your colonists will need to be able to walk to the rocket so if you needed geologists in the rocket and they are way over on the other side of the map, you need to move them closer.

[maLENstwo]

Yeap I was sending it for an expedition and it works automatically but it takes quite long to start after fully refuel of the rocket. For me its looks like some bug or something but maybe its just take some time on Mars and I didnt know that till now. ;)