A Lopsided Supernova, Orbital Espresso and More Cosmic Wonders

An exploding star reveals its secrets and an astronaut takes a coffee break in this week’s best space pictures

Watery curtains flowing from a Saturn moon, NASA cleaning a telescope with snow, and an astronaut sipping the first espresso in space feature among our picks for the best space-related images of the week.

Through the Curtains

Saturn's moon Enceladus is famous for spitting into space—in the early 2000s, NASA's Cassini spacecraft showed that the icy body has plumes of water gushing from cracks in its south polar region. Based on images of the jets, scientists think a pocket of water lies beneath the moon's icy crust that is perhaps as big as Lake Superior. Cassini has even been able to zip through and taste the plumes, finding that they contain salt, organic compounds and other ingredients that help sustain life here on Earth.

But now, Cassini scientists think the plumes of Enceladus may be an illusion. Water is still pouring out of the moon, but the eruptions are more like waving curtains than discrete jets, according to new simulations presented this week in Nature. The cracks that vent the plumes are not perfectly straight, and because of our viewing angle, "folds" in the curtains of erupting water seem brighter, creating phantom jets. Figuring out exactly how water spews from Enceladus should reveal more about its subsurface lake and whether it has the potential to host alien life.

Lopsided Explosion

Seen through Hubble's eye, the sweeping form of supernova 1987A looks like a study in symmetry. But if you track high-energy radiation escaping from the stellar blast, things start to go off-kilter. New data from NASA's Nuclear Spectroscopic Telescope Array shows that the still expanding debris is actually lopsided, a finding that adjusts our understanding of the mechanism that triggers massive stars to explode.

Stars explode for different reasons, and the way they blow up tells us a lot about the initial objects that set off the blast. When very massive stars burn through their internal hydrogen fuel, they become unstable, until the star's core collapses. This creates what astronomers call a type II supernova. The new data on 1987A back up computer models that suggest these star cores transform from symmetric spheres to wobbly objects made of turbulent plumes of hot gas, NASA reports. The work could help answer a long-standing mystery: why do some stars collapse into dense corpses called neutron stars while others form black holes.

Snow Blast

Cleaning your glasses can be a challenge—pesky particles of dust can scratch the lens if you don't wipe with care. So how does NASA safely clean the "eyewear" of its next-generation space telescope? Here, two engineers are testing a cleaning method that involves blasting the telescope's mirrors with carbon dioxide snow.

NASA's James Webb Space Telescope is a giant new space telescope due to launch in 2018 that is sometimes billed as the successor to Hubble. It will use a 270-square-foot primary mirror, made of 18 hexagonal segments, to stare into space and find some of the most distant objects in the universe. Due to its sensitivity, keeping those mirror parts clean as the telescope gets built will be crucial to the mission. "The snow-like crystals knock contaminate particulates and molecules off the mirror," Lee Feinberg, NASA optical telescope element manager, says in a release. "Small dust particles or molecules can impact the science that can be done with the Webb. So cleanliness especially on the mirrors is critical."

Rocky Road

Mars is full of hazards, from extreme temperatures to planet-wide dust storms. But the latest woe for NASA's Curiosity rover is surprisingly mundane: a rock in its shoe. This image, taken by the Mars Hand Lens Imager (MAHLI) on the rover's robotic arm, shows a large chunk of Martian rock stuck in the treads of its aluminum wheels. Rover drivers could try to shake the rock free, but they think it is safer to let it fall out on its own, according to New Scientist.

Curiosity has been trundling across Mars since August 2012, heading for a 3-mile-high mountain called Mount Sharp. Along the way its wheels have suffered an unexpected amount of damage—the surprisingly hard terrain has caused punctures, fissures and dents that have slowed the rover's progress. Mission managers think the wheel troubles are manageable, though, if they carefully pick their paths.

Orbiting Espresso

Italian astronaut Samantha Cristoforetti channels Captain Janeway from "Star Trek: Voyager" as she takes a sip of the first espresso brewed on the International Space Station. Created with help from the coffee company Lavazza, the orbiting espresso machine had to be designed to compensate for the unusual fluid dynamics experienced in microgravity and to comply with ISS safety requirements, Gizmag reports.

Seen here in a shot released via Twitter, Cristoforetti was able to sip her space cuppa in a more natural way, thanks to a special drinking vessel designed by Portland State University. "This 3D-printed plastic cup uses surface tension to keep the coffee in the cup, and capillary action to let astronauts drink as if out of a normal cup on Earth," Gizmag writes. "The latter also helps in producing the 'crema' of an espresso."