The flea when jumping accelerates 50 times faster than a space shuttle. Although fleas cannot fly, they can jump over seven inches (18 cm) high and thirteen inches (33 cm) long, that is about one hundred and fifty times its own length. Without its outer shell it would get smashed by the velocity of the jump, and especially on its landing.

Acceleration is the change in speed of an object over time, often measured in "g" 's, with one g equal to the acceleration caused by gravity on Earth (9.8 meters / 32.2 feet per square second). Fleas experience 100g, while the Space Shuttle peaked at around 5g. The flea's secret is a stretchy rubber-like protein which allows it to store and release energy like a spring.

More Info: www.pests.org