Cassini finds oxygen atmosphere around Saturnian moon

The Cassini-Huygens mission has identified an oxygen-carbon dioxide atmosphere around Saturn's second-biggest moon, Rhea - the first time a spacecraft has captured an oxygen atmosphere from a world other than Earth.
The atmosphere is unbreathable, to say the least, with an oxygen density around five trillion times less than Earth’s. But there's potentially enough, says the Cassini team, to drive complex chemistry.
"The new results suggest that active, complex chemistry involving oxygen may be quite common throughout the solar system and even our universe," said Dr Ben Teolis, a Cassini team scientist based at Southwest Research Institute in San Antonio.
"Such chemistry could be a pre-requisite for life. All evidence from Cassini indicates Rhea is too cold and devoid of the liquid water necessary for life as we know it."
The ion and neutral mass spectrometer 'tasted' peak densities of oxygen of around 50 billion molecules per cubic meter. It also found peak densities of carbon dioxide of around 20 billion molecules per cubic meter, as well as clear signatures of flowing streams of positive and negative ions, with masses that corresponded to ions of oxygen and carbon dioxide.
The team believes the atmosphere is sustained by high energy particles bombarding its icy surface and kicking up atoms, molecules and ions into the atmosphere.
"Rhea's oxygen appears to come from water ice on Rhea's surface when Saturn's magnetic field rotates over the moon and showers it with energetic particles trapped in the magnetic field," said Professor Andrew Coates from University College London.

SpaceX wins approval for first commercial spacecraft re-entry

The Federal Aviation Administration (FAA) has awarded SpaceX the first-ever commercial license to re-enter a spacecraft from orbit.

The one-year license gives the green light to next month's launch of SpaceX's Falcon 9 rocket, carrying the company's Dragon capsule. This is expected to orbit the Earth at more than 17,000 miles per hour, reenter the Earth’s atmosphere and land in the Pacific Ocean a few hours later.

It's something that's never been achieved by a private company before. Indeed, only five nations - the US, Russia, China, Japan and India - have managed it, along with the European Space Agency.

"Milestones are an important part of space exploration and SpaceX achieved a very important one today," said Doug Cooke, associate administrator for NASA's Exploration Systems Mission Directorate.

"I congratulate SpaceX on this landmark achievement and wish them the best with their launch of the Dragon capsule."

The flight also marks the first stage in NASA’s Commercial Orbital Transportation Services program, bringing commercial supply services to the International Space Station.

After the Space Shuttle retires, SpaceX will make at least 12 flights to carry cargo to and from the ISS.

"Congratulations to the SpaceX team for receiving the Federal Aviation Administration's first-ever commercial license to reenter a spacecraft from Earth orbit," said NASA administrator Charlie Bolden.

"With this license in hand, SpaceX can proceed with its launch of the Dragon capsule. The flight of Dragon will be an important step toward commercial cargo delivery to the International Space Station. NASA wishes SpaceX every success with the launch."