Unlike the American GPS, Russian GLONASS, and European Galileo systems, which use median Earth orbit satellites, BeiDou-1 uses satellites in （ ）. A: Geostationary orbit B: Circular orbit C: Sun-synchronous orbit D: Near polar orbit

How many conic sections exist in the Earth-Mars transfers? A: Earth-centered parabola orbit B: Sun-centered elliptical orbit C: Earth-centered hyperbola orbit D: Mars-centered hyperbola orbit

Mercury complete its orbit around the sun in only ______.

The newly launched satellite is ______ from its designed orbit. A: deviating B: detaching C: diffusing D: vibrating

In recent years a number of ________ satellites have been put into orbit. A: communication B: transportation C: transportations D: communications

Since the launching of the first artificial ________ in 1957, thousands of “man-made moons” have been rocketed into(飞速进入) the Earth’s orbit.

orbit [br][/br] (1.0) A: 咨询 B: 轨道 C: 排演 D: 练习

the next three flights will test rendezvous of the manned spacecraft and the unmanned lunar landing craft in the earth orbit. A: docking B: communication C: appointment D: unification

Scientists managed to _____ a satellite in orbit around the planet Venus. A: laundry B: set C: launch D: set out

The company says it will take telecommunications equipment into an around the moon by the end of 2022. A: habit B: rabbit C: orbit D: parrot