Original sentence: While it is believed that some of the design variants commonly described – specifically those based on the Dyson shell – are impractical, if not physically impossible to our capabilities, design variants of the sphere based on orbiting satellites or solar sails do not require any major theoretical breakthroughs in our basic scientific understanding for their construction
Edited sentence: While it is believed that some of the design variants commonly described – specifically those based on the Dyson shell – are impractical, if not physically impossible, design variants of the sphere based on orbiting satellites or solar sails do not require any major theoretical breakthroughs in our basic scientific understanding for their construction