italy12- Yes, federal student loans can go into default if you do not pay your minimum payment each month. Generally, federal student loans go into default if you do not make payments for one year.
There are a few programs to help you if you cannot pay for your student loans. The government has started a program that allows your monthly payment to be adjusted according to your income. Therefore, if you do not make very much money your loan payment will not be as large as someone who makes more money.
However, keep in mind that if your monthly payments are very small it will take you longer to pay off the loan. The longer you take to pay off your loan the more interest you will accrue. This interest will end up costing you more in the long run.