11. North Korea alarmed the region in 1998 by firing a multistage rocket over Japan and into the Pacific. 12. As disposable multistage rockets launching tiny capsules provided the first generation of spacecraft, the shuttles are the second generation. 13. This design emulates an air-launched multistage rocket with two recoverable stages : the tow plane and the glider itself. 14. After completing its primary burn, the first stage of the multistage rocket detached from the second stage as usual. 15. In 1929, Tsiolkovsky proposed the construction of multistage rockets in his book " Space Rocket Trains " ( ). 16. The multistage rocket launches from Peterson Field, near Colorado Springs, Colorado, lands on the Moon, and returns to Earth. 17. North Korea shocked its neighbors last August when it sent a multistage rocket over Japan and into the Pacific Ocean. 18. To ensure clean separation and prevent contact, multistage rockets may have small retrorockets on lower stages, which ignite upon stage separation. 19. North Korea alarmed Northeast Asia a year ago by sending a multistage rocket sailing over northern Japan and into the Pacific Ocean. 20. After North Korea fired a multistage rocket on Monday, defense and intelligence officials said they had closely monitored preparations for the launch.
