These are the most frequently used words in another edition of this book.
above
across
air
another
apollo
astronomers
atmosphere
away
below
billion
called
cloud
craft
craters
day
down
dust
earth
enough
even
ever
far
few
field
first
form
found
galileo
gas
giant
heat
hours
image
jupiter
kilometres
last
left
life
light
long
look
lunar
mariner
mars
mercury
might
million
mission
moon
nasa
neptune
new
now
ocean
orbit
per
pictures
pioneer
place
planet
point
pole
probe
red
right
rings
rock
saturn
saw
scientists
second
see
seen
size
sky
small
solar
something
soviet
space
star
still
sun
surface
system
take
telescope
temperature
three
time
top
two
uranus
venus
viking
voyager
water
wind
world
years