1.Its maiden voyage was on August 30、 1984. Since then it has flown more than any other Spacecraft having completed 39 successful missions one of which was the launching of the Hubble Space Telescope. Discovery now resides at the Smithsonian Museum in Washington、 DC.Item#:1Number of sheets:1 SheetDifficulty:EasyAssembled Size:3.9" x 2.73" x 1.95" (10 x 7 x 5 cm)2.The Space Shuttle Endeavour is one of the retired orbiters of the Space Shuttle program of NASA、 the space agency of the United States. Endeavour was the fifth and final spaceworthy NASA space shuttle to be built、 and first flew in May 1992 on mission STS-49 and its last mission STS-134 was in May 2011.Item#:2Number of sheets:1 SheetDifficulty:EasyAssembled Size:3.9" x 2.73" x 1.95" (10 x 7 x 5 cm)3.The First Space Shuttle built was the Enterprise. It was built by Rockwell International to be used by NASA for test flights in the atmosphere. The Enterprise had been designed so it could be refitted and used for orbital flight. However、 this plan proved too expensive and so it was decided to simply build a new shuttle called Challenger. The Enterprise now resides in the Intrepid Museum in New York City.Item#:3Number of sheets:1 SheetDifficulty:EasyAssembled Size:3.9" x 2.73" x 1.95" (10 x 7 x 5 cm)4.The RQ-170 Sentinel was a "Stealth" drone that crashed in Iran on what was believed to be a surveillance mission. It was dubbed the ¡®Beast of Kandahar¡¯ after being pictured flying in Afghanistan. Little is known about the drone although it is believed to have radar-evading capabilities.Item#:4Number of sheets:1 SheetDifficulty:EasyAssembled Size:4.13" x 1.56" x 1.56" (10.6 x 4 x 4 cm)5.The Mitsubishi Zero is a long-range fighter aircraft operated by the Imperial Japanese Navy Air Service. When first introduced early in World War II、 the Zero was considered the most capable carrier-based fighter in the world、 combining long range capabilities with excellent maneuverability.Item#:5Number of sheets:1 SheetDifficulty:EasyAssembled Size:4.88" x 3.90" x 0.78" (12.5 x 10 x 2 cm)