Not only does the dewar experiment eliminate the expense of the complex flight apparatus, it also allows for the testing of many more samples than on previous missions. We would like to optimize conditions for a particular protein. Normally, that is an empirical process in which you set up a lot of samples and see which perform best. Because we can fly so many samples in one dewar, we can use it as a mechanism for optimizing conditions quickly and cheaply. The only requirement was time.
Extensive time is required in a low-gravity environment for the slow thaw and slow growth.
The 16 days of a shuttle mission is the most time that NASA could provide. McPherson and Koszelak estimated that it would take at least eight days for the proteins to thaw, leaving an inadequate eight days for growth. So eight years passed without testing the dewar concept. U.S. experiments would be ferried to and from Mir by the shuttle and by Russian craft and would stay onboard the Russian station for months at a time. The international agreement finally offered the two scientists a way to test their dewar experiment.