Compressed gas is used to drive the missile to the surface before its engine ignites.

The Discovery's three engines had not yet ignited when the countdown ended.

Once their engines ignited, there was no stopping them.

The engine caught fire and ignited the fuel tanks in the 707's wings.

If by any miracle either officer had survived the impact, the explosion when the engine ignited would have finished them off.

The arms pulled away just after the engine ignited, releasing the missile.

The ship's engines had ignited, perhaps for the first time ever.

The missile dropped clear of the wing and fell thirty feet before its engine ignited.

The next launch was on 10 April 1968, and was also a failure because the engine did not ignite.

Upon breaking the surface of the ocean, and righting itself, the engine ignited.