How involved should your PhD adviser be in your project? I just completed my first year at a PhD program at a University in the United States. It's been a semester since I joined a lab and I'm slightly confused about my decision at the moment. I feel like my academic advisers are not as involved in my project as they should be. 

I'm working on a joint project between two professors in a field that is new to them, besides their expertise on instrumentation. Both my advisers are well accomplished in their respective fields but their experience in the area that my project is concerned with is (at least on paper) substantially less (only one publication from the lab so far). Besides, there is only one other graduate student involved on this project while all other group members work in a different area, making it difficult for me to get any help from members in the lab. On top of this, I meet my advisers only once every 2-3 weeks and although they are extremely patient with regards to my queries, their feedback hasn't been very useful yet. 

While I was aware of this situation before deciding to join the lab, I went ahead with the project for its future prospects and overlap of required skill set with mine. It also offered the opportunity to build up a lab almost from scratch with very experienced advisers, which I thought, was great. While I don't hate working on my project, I'm concerned since I haven't made much progress and am not sure if what's happening is normal. Both my advisers are experts in instrumentation, which is a major hurdle in the project (and hasn't been tackled by any other group yet), but aren't aware of the current scientific problems in the field. 

Finally boiling down to my questions: 

(i) I often find myself worrying that the problem I end up working on for the next few years as a graduate student might turn out to be insignificant or turned down as trivial by experts in the field. Am I thinking too much? 

(ii) I often hesitate digging deeper into articles in my field (not directly related to my project) wondering if it's useful at all, considering that I'd be all by myself if I pursue it and would thus stand no chance against other research groups that are actively involved in the field. Is that reasonable?

(iii) Would it be rude to confront my advisers with these concerns? 

(iv) Would it suffice for me to get help from another faculty on campus and continue with my project?
1) Email your advisors short (few sentences) progress reports every week or less. This forces you to move at a quicker rate than 2-3 weeks, and keeps them more invested in your progress.

2) As a junior student I suggest that for now you trust your advisors and peers and grind through this project. Researchers tend to always be critical of their own work, no matter how good it is.

3) It would be ideal to work side by side with a more experienced graduate student or advisor.

4) Part of a PhD is intellectual independence. You should not be afraid about pursuing an area if no one else is pursuing it, so long as you can see its merits. Why work on something that everyone else is working on?