Today’s Deep Space Extra offers the latest reporting and commentary on space related activities from across the globe. NASA has assembled scientists as well as engineers to help it scout out the most promising landing sites on Mars for future human explorers. Maybe dry ice, not flowing water is responsible for Martian gullies. NASA’s Cassini spacecraft transmits new images of Saturn’s geologically active moon Enceladus. Comet Catalina is finally ready for early morning viewing. Spacewalking U.S. astronauts free a jammed transporter on the International Space Station. Russia’s upgraded Progress MS-1 space freighter heads for a docking with the space station early Wednesday. SpaceX scores a successful Falcon 9 first stage landing. Lower launch costs, smaller spacecraft fueling new interest in space commerce, says historian.

Human Deep Space Exploration

NASA’s Plans for Sending Humans to Mars
Sky and Telescope (12/21): Perhaps two decades from placing human explorers on Mars, NASA has already assembled a workshop of experts in science as well as engineering to plot a landing site that is of scientific value as well as close to resources needed to grow food, generate oxygen and water as well as produce new rocket fuel.

Unmanned Space Exploration

Dry ice, not water, responsible for many gullies on Mars, study says
Los Angeles Times (12/21): A new study suggests that all the excitement about flowing water causing seasonal gullies on Mars has an alternative explanation. The outflows could be attributed to eruptions of subsurface carbon dioxide ice, according to Nature Geoscience.

Behold, Enceladus! Awesome Photo Shows Off New Features on Saturn Moon
Space.com (12/21): Cassini, the U.S., European spacecraft orbiting Saturn makes a final close flyby of the moon Enceladus, transmitting images of the icy moon’s terrain.

How to See Comet Catalina in the Early-Morning Sky
Space.com (12/21): The comet Catalina, discovered in late 2013, is becoming easier to observe at day break in the constellation Virgo with the aid of binoculars or a telescope.

Low Earth Orbit

Spacewalking astronauts fix station’s stuck rail car
Reuters (12/21): Spacewalking NASA astronauts Scott Kelly and Tim Kopra unjammed a mobile transporter outside the International Space Station early Monday. On the ground, managers were concerned the equipment cart might cause damage as a Russian cargo capsule attempts to dock early Wednesday.

Upgraded Progress MS launches en route to ISS
NASASpaceflight.com (12/21): Designated MS-1, Russia’s latest resupply mission to the six person International Space Station embarked on a two day flight early Monday. The Russian freighter carries 2.8 tons of propellant, crew supplies and equipment. Equipped with major upgrades designed to be shared with Russia’s piloted Soyuz, the resupply craft is expected to carry out an automated docking early Wednesday.

Commercial to Orbit

SpaceX Successfully Lands Rocket After Launch of Satellites Into Orbit
New York Times (12/21): SpaceX launched a Falcon 9 rocket with 11 Orbcomm communications satellites Monday evening, followed by an upright landing of the rocket’s first stage near the Cape Canaveral, Fla., launch site. The launching was the first for the Falcon 9 since a June 28 explosion of the rocket following a lift off on a NASA contracted re-supply mission to the International Space Station.

Space commercialization: finally ready for liftoff?
The Space Review (12/21): Lower launch costs and smaller but capable spacecraft are contributing to a wider interest in the possibilities of commercial space, writes Johnathan Coopersmith, a Texas A&M University historian. Coopersmith tracked the sentiments of the aerospace industry as well as those from the energy, health care and other fields participating in the first Space Commerce Conference and Exposition last month in Houston.