I think it is good to try and keep politics out of space if possible! Of course sometimes that can be difficult but space definitely benefits from working together. For example, I think that humans will only be able to carry out a successful mission to Mars if it is an international collaboration.
The International Space Station (ISS) is a good example of working together, pooling resources and expertise for the benefit of all humans.
It is very important to note that cooperation in space can happen without the EU and the European Space Agency (ESA) actually has members part of it outside of Europe.
I think it is great for our democracy to have a debate about the EU and it is of course a personal choice whichever way you choose.