After D-Day, General Groves ordered a team of scientists to follow eastward-moving victorious Allied troops into Europe to assess the status of the German nuclear program (and to prevent the westward-moving Soviets from gaining any materials or scientific manpower). They concluded that, while Germany had an atomic bomb program headed by Werner Heisenberg, the government had not made a significant investment in the project, and it had been nowhere near success. Similarly, Japan's efforts at developing a nuclear weapon were starved of resources. The Japanese navy lost interest when a committee led by Yoshio Nishina concluded in 1943 that "it would probably be difficult even for the United States to realize the application of atomic power during the war".