пройдёт некоторое время прежде, чем
• It will be some time [or Some time will pass (or elapse)] before direct investigations will be really feasible.
Русско-английский научно-технический словарь• It will be some time [or Some time will pass (or elapse)] before direct investigations will be really feasible.
Русско-английский научно-технический словарь