1.   After dropping off tanks of liquid oxygen to fuel the next ship, you re-enter the atmosphere.

2.   In that case, we would think first of burning hydrocarbons with liquid oxygen, or even using the hydrogen-oxygen propellant combination.

3.   The engines of the Atlas burned a modified aviation fuel, similar to kerosene, with liquid oxygen.

4.   Zubrin proposes burning methane with liquid oxygen for the return trip to Earth.

5.   The two prototype pumps, installed in the eastern Paris suburbs of Colombes and Rueil-Malmaison, use liquid oxygen.

6.   And using liquid oxygen rather than gas means there are lots of oxygen atoms at the silicon surface.

7.   Another relies on liquid oxygen, not the most portable of materials.

8.   A Californian aerospace company proposes to harvest liquid oxygen from the atmosphere, which would then be used to blast a space orbiter into space.

9.   But within minutes, incoming air would begin to supplement liquid oxygen.

10.   Concealed within are two containment areas -- a bladder in the forward end for liquid oxygen and a larger compartment below for liquid hydrogen.