jupiter

Thanks to a surface covered in liquid water, Jupiter's moon Europa serves as the prime suspect for bodies in our solar system harboring extraterrestrial life. For the most part though, speculation has assumed the life on Europa would be microscopic, similar to the chemical and rock-eating microbes found atop undersea volcanic vents on Earth. However, a new study estimates the level of oxygen in Europa's seas may be high enough to support fish-sized life. Hello, alien sushi.

Despite its gusty reputation as a “gas giant,” Jupiter’s blood-red clouds hide a dense, rocky core that’s perhaps 20 times as massive as Earth. That core blocks any spacecraft’s passage through the center of the planet, but even a detour through the clouds would be a disaster.

A radar device aboard ESA's Mars Express orbiter has allowed scientists to peek beneath the surface from afar, and the success with this research is now prompting them to think up other spots in the solar system that would be ideal for this sort of examination.

NASA hopes to someday use a robot like Bill Stone's DepthX to explore Europa, a frozen moon of Jupiter and one of the most probably places in our solar system to support life.

NASA's Ion Engine

1. Charge the Fuel
Xenon is an inert gas, seemingly useless for rocketry. Before it´s used as fuel, the engine must convert it into an electrically charged gas, also called a plasma. An electron emitter fires electrons at the xenon gas. When an electron hits a xenon atom, it strips off an additional electron from the atom´s shell to create a positively charged xenon ion.