CU Aerospace and its University of Illinois teammate propose the design, sub-component fabrication and preliminary test of an UltraSail "Cubesat" 20 m2 solar sail spacecraft leading to a flight test in low Earth orbit. The complete flight test program consists of: preliminary design and sub-component tests; fabrication and assembly of a University of Illinois Cubesat spacecraft bus adapted to solar sail deployment; spaceflight qualification testing; and the flight test. The proposed innovation will demonstrate a scalable flight test in a 3 kg package of a high performance 200 m long solar sail plus two Cubesats to achieve a solar sail areal density of 5 gm/m2, and a large cost reduction factor for flight test of advanced solar sails. Successful development of the UltraSail solar sail will enable very high energy inner heliosphere and interstellar scientific missions with large scientific payloads. In addition, near-earth missions, such as Heliostorm for early warning of solar storms, will provide more warning margin as the solar sail performance is increased with UltraSail technology.