The program of the mini-satellite PROTEUS, on which CoRoT was to be set up, fell behind, and during this time three events were going to make the project evolve:
The scientific program of the new CoRoT is much more ambitious, and the instrument preparation is thus very different.
The CCD matrixes can now be adapted to conditions in space, and can observe a lot of stars at the same time. They are better able to stand the environmental difficulties (light diffused by the Earth) and are of better quality (efficiency, uniformity).
The realization started in 2000 and continued with the assembly of the sub-systems, despite some financial and technical hazards. Before that, the project had to demonstrate its feasibility, and find foreign partners to reduce the costs, etc.
It was about to demonstrate that, in the frame of the program of small missions of the CNES, it is possible to construct a mission able to reach its scientific objectives :
To do that, an orbit must be determined, and it must be proven that the perturbations submitted to the mission do blur the intended signal. Then it is necessary to expose the results of the study to convince the experts of the review groups.
Despite a few difficulties, it was a great success!