How to solve the cosmic ray knee problem

It is shown that recent experimental data in the knee region contradict each other and new approaches to the so – called "knee problem" are needed to solve this complicated and old problem. The PRISMA project proposed by us is based on an idea that the main EAS component – hadrons have to be measured first of all. Special detectors have been developed for this purpose. It is shown using Monte-Carlo simulations that only full-scale recording of hadronic component could give us a key to the solution. The location of such experiment should be at high altitude (the higher, the better) and that is why we proposed to combine the central part of the PRISMA array with that of the LHAASO project array to be constructed in Tibet. If the proposal will have success then the "knee problem" will be solved in a few years.