North Korea announced plans Friday to blast a satellite into space on the back of a long-range rocket, a provocative move that could jeopardize a weeks-old agreement with the U.S. exchanging food aid for nuclear concessions. The North agreed to a moratorium on long-range launches as part of the deal with Washington, but it argues that its satellite launches are part of a peaceful space program that is exempt from any international disarmament agreements. The U.S., South Korea and other critics...