Last week SPACE.com readers and experts shared their memories of the day of the Columbia accident, we looked at the evolving threat of Earth-circling orbital debris and a close conjunction of Jupiter and the moon amazed stargazers all over the world. See the top stories of the last week here. <p>FIRST STOP: Space Shuttle Columbia Tragedy: Share Your Thoughts
We ask SPACE.com readers and experts for their memories of the day of the Columbia accident. [<a href=http://www.space.com/19435-columbia-shuttle-disaster-reader-memories.html>Full Story</a>] <p>NEXT: Space Junk Menace: How to Deal with Orbital Debris
The saga of what steps must be taken to deal with the evolving threat of Earth-circling orbital debris is a work in progress. Dangerous space junk comes in all sizes and, indeed, has become a “growth industry” in and of itself. [<a href=http://www.space.com/19445-space-junk-threat-orbital-debris-cleanup.html>Full Story</a>] <p>NEXT: On Mars, Dry Ice 'Smoke' Carves Up Sand Dunes
Thawing dry ice causes seasonal changes in dunes on Mars, a new study suggests. [<a href=http://www.space.com/19452-mars-sand-dunes-dry-ice.html>Full Story</a>] <p>NEXT: NASA Eyes 'Hedgehog' Invasion of Mars Moon Phobos
Stanford researchers have created new spiky rovers called hedgehogs that could be used for a mission on Phobos, a Martian moon. How they work and where the project stands. [<a href=http://www.space.com/19342-space-hedgehogs-mars-moon-phobos.html>Full Story</a>] <p>NEXT: Giant Mars Crater Shows Evidence of Ancient Lake
Groundwater might lurk under the surface of Mars, hinting that a vast amount of life might once have potentially lived there. [<a href=http://www.space.com/19348-giant-mars-crater-water-lake.html>Full Story</a>] <p>NEXT: Space Explosion to Blame for Tree Ring Mystery, Astronomers Say
A spike in rare chemicals recorded in tree rings from 775 A.D. may have been caused by a space explosion called a gamma-ray burst, according to a new study. The study solves a long-standing tree ring mystery. [<a href=http://www.space.com/19340-tree-ring-mystery-gamma-ray-burst.html>Full Story</a>] <p>NEXT: NASA's Planet-Hunting Kepler Telescope Stalled by Glitch
NASA's prolific planet-hunting Kepler Space Telescope has been placed in a precautionary "safe mode" after engineers noticed a problem with the instrument's orientation mechanism. [<a href=http://www.space.com/19360-kepler-telescope-alien-planets-glitch.html>Full Story</a>] <p>NEXT: Close Encounter of Jupiter and Moon Wows Stargazers
A close conjunction of Jupiter and the moon amazed stargazers all over the world last night. Readers submitted photos of what the close pairing looked like. [<a href=http://www.space.com/19377-jupiter-moon-encounter-stargazers-photos.html>Full Story</a>] <p>NEXT: Is Space Big Enough for Two Asteroid-Mining Companies?
The second company to jump into the asteroid-mining business isn't worried about competition from its rival, saying that the resources of space are vast enough to support an entire extractive industry off Earth's surface. [<a href=http://www.space.com/19380-asteroid-mining-spaceflight-competition.html>Full Story</a>] <p>NEXT: Astronaut's Video Reveals Secret of Zero-G Fingernail Clipping
The Canadian Space Agency released a video of Chris Hadfield explaining how to cut fingernails in space. [<a href=http://www.space.com/19382-zero-gravity-fingernails-clipping-video.html>Full Story</a>] <p>NEXT: How NASA Revealed Sun's Hottest Secret in 5-Minute Spaceflight
NASA's Hi-C (High-Resolution Coronal Imager) mission launched on a suborbital sounding rocket in July 2012 to take quick, up-close snapshots of the surface of the sun. [<a href=http://www.space.com/19400-sun-corona-secrets-suborbital-telescope.html>Full Story</a>] <p>NEXT: NASA's Opportunity Rover Begins Year 10 on Mars
NASA’s Mars rover Opportunity landed on the Red Planet nine years ago today. Now, the long-lived rover is beginning an astounding Year 10 on the Red Planet. [<a href=http://www.space.com/19411-mars-rover-opportunity-year-ten.html>Full Story</a>]
