11.3
The United States' first space station
What is Skylab
point on the celestial sphere directly above an observer
What is zenith
narrow, dark lines in a spectrum produced by a gas ab sorbing certain colors
What are absorption lines
first manned mission to land on the moon
What was Apollo 11
first spacecraft designed to be reused
What is the spaceshuttle
point on the celestial sphere directly below an observer
What is nadir
lets scientist study space using "colors" of light that the humand eye cannot see. studies objects that are located where their visible light connot reach Earth, such as inside nebulae
What are radio telescopes
tested teh new spacecraft systems iun Earth orbit
What was Apollo 7
type of rockets taht have been used for centrues to launch fireworks and small military rockets
What are liquid-fuel rockets
path on the celestial sphere that the sun follows in a year
What is ecliptic
spacecraft leave Earth's gravity without reaching escape velocity with this assistance
What is using its rockets to push it away
tested lunar module in Earth orbit
What is Apollo 9
first artifical object to orbit the Earth
What is Sputnik I
unmanned spacecraft launched specifically to explore the unknown
What is a space probe
most famous network of navigational satelites
What are Global Positioning System (GPS)
first manned spacecraft to orbit the moon
What was Apollo 8
United States' first satellite
What is Explorer I
special orbits that allows a satellite to alter its orbit simply by adjusting its speed at the proper time
What is Hohmann transfer orbit
first mission to launch more than one astronaut aboard a singel spacecraft
What was Voskhod 1
dress rehearsal for the actual moon landing, with astronauts descendig partway to the moon's surface in the lunar module