On his deathbed, Brand admits that he had solved the problem before the "Endurance" mission departed, and that he had determined that the relocation project is impossible without additional data from a black hole's singularity.
He had solved the problem before the "Endurance" mission departed, and that he had determined that the relocation project is impossible without additional data from a black hole's singularity. This is what Brand admits on his deathbed.