there are several language that will became the international languages..

in economic we have Chinese..

in technology we have Japanese..

in globally we have English for now, but perhaps, Chinese or japanese can beat up the english..

Yes, I do. In these days, English is the international language.

I mean not only on earth but also in space must be the base to consider English's importance today.

Sorry, my poor English.  Now you can tell I care too much about my own language♪

Yes, but not a loud one. In my viewpoint, English is so popular all over the world. The number of people speaking English for communication everyday proves it. Another evidence is that almost all specailized knowledge are written in English. However, the importance of any language is strongly related to the influence of it. Maybe recently a huge amount of persons need it, but I can't see a increasing demand on it but other languages, such as Mandarin and Spanish.

yes and no

I want you to think your mother language the most important anywhere you are. Then English should come next as an international language.   English is the most important not only on the earth but also in space (at ISS)!