A space suit is a garment worn to keep a human alive in the harsh environment of outer space, vacuum and temperature extremes. Space suits are often worn inside spacecraft as a safety precaution in case of loss of cabin pressure, and are necessary for extravehicular activity (EVA), work done outside spacecraft. Space suits have been worn for such work in Earth orbit, on the surface of the Moon, and en route back to Earth from the Moon. Modern space suits augment the basic pressure garment with a complex system of equipment and environmental systems designed to keep the wearer comfortable, and to minimize the effort required to bend the limbs, resisting a soft pressure garment’s natural tendency to stiffen against the vacuum. A self-contained oxygen supply and environmental control system is frequently employed to allow complete freedom of movement, independent of the spacecraft.
The existence of ample amounts of hydrogen in the subsurface ocean of Enceladus indicates that microbes--if any exist there--could use it to obtain energy by mixing with carbon dioxide dissolved in water. This particular chemical reaction, termed methanogenesis, because it manufactures methane as a byproduct, may have been of critical importance in the emergence of life on our planet. "For the smallest craters that we're looking at, we think we're starting to see where the Moon has gone through so much fracturing that it gets to a point where the porosity of the crust just stays at some constant level. You can keep impacting it and you'll hit regions where you'll increase porosity here and decrease it there, but on average it stays constant," Dr. Soderblom continued to explain to the press on September 10, 2015. In addition, the newly collected data derived from the GRAIL mission helps astronomers redefine the late heavy bombardment--a proposed episode that occurred about 4 billion years ago, during which a heavy shower of projectiles pelted the bodies of the inner Solar System, including Earth and its beloved Moon, creating heavy lunar cratering in the process. The concept of the late heavy bombardment is primarily based on the ages of massive near-side craters that are either within, or adjacent to, dark, lava-flooded basins (lunar maria), that are named Oceanus Procellarum and Mare Imbrium. However, the composition of the material existing on and below the surface of the lunar near-side indicates that the temperatures beneath this area are not representative of Earth's Moon as a whole at the time of the late heavy bombardment. The difference in the temperature profiles may have caused scientists to overestimate the amount of crater-excavating projectiles that characterized the late heavy bombardment. New studies by GRAIL scientists indicate that the size distribution of impact craters on the lunar far-side is a more accurate reflection of the crater-forming history of the inner Solar System than those pock-marking the near-side.