The three subsequent Discoverers were successfully orbited, but all of their cameras failed when the film snapped during loading. Ground tests determined that the acetate-based film became brittle in the vacuum of space, something that had not been discovered even in high altitude, low pressure testing. The Eastman Kodak Company was tasked with creating a more resilient replacement. Kodak developed a technique of coating a high-resolution emulsion on a type of polyester from DuPont. Not only was the resulting polyester-based film resistant to vacuum brittling, it weighed half as much as the prior acetate-based film.