Service members and civilian Defense Department employees who take part in the Thrift Savings Plan will soon have greater flexibility in their retirement planning. The Defense Department is gearing up to offer TSP participants the opportunity to participate in new Roth option, which would tax contributions the year they are made. Roth-option contributions would then be tax-free upon retirement. The change allows TSP participants the option of investing before- or after-tax dollars into their retirement accounts. The maximum allowable contribution for 2012 is $17,000. Participants age 50 and older can invest up to $5,500 more than the maximum in catch-up contributions.