They need to make metamaterial layers to achieve reflectivity. They have made the layers in the lab with over 70% reflection of light for less than 0.7 grams per square meter.
In phase 2, they will fabricate and test the material. They will explore how to scale fabrication. They will refine the solar sail design and explore making the boom lighter.
The goal is sub-$100 million missions that could be sent out of the solar system 30 times farther than Pluto with less than 20 year travel time.