Solar sail is a high potential sailing craft for interstellar exploration.The area of the first flight solar sail demonstrator named "IKAROS"is 200 square meters.Future interplanetary missions will require solar sails at least on the order of 10000 square meters(or larger).Due to the limitation of ground facilities,the size of experimental sample should not be large.Furthermore the ground experiments have to be conducted in gravitational field,so the gravity effect must be considered in a ground test.To obtain insight into the solar sail membrane dynamics,a key membrane flutter(or limit cycle oscillations)experiment with light forces acting on it must be done.But one big challenge is calibrating such a tiny light force by as a function of the input power.