Pierre Ducharme / Reuters
The space shuttle Atlantis lands at NASA's Kennedy Space Center in Florida on July 21, ending 30 years' worth of shuttle missions. Click on the image to see msnbc.com's "Year in Space" slideshow.
During 2011, NASA said goodbye to the Spirit Mars rover and the space shuttle program — but there's hope that during 2012, new players will strut their stuff on the space effort's huge stage, stretching from Cape Canaveral to the Red Planet.
This is my 15th annual "Year in Space" roundup, and in all those years I can't think of a starker time of transition between the year that's past and the year to come. The space shuttles are being readied for museums, and work hasn't yet started on the big rocket that NASA says it will need for the next era of human space exploration. The space agency's plans for commercializing operations in low Earth orbit could well be tied up in budgetary knots, and there are questions about how much farther its robotic Mars exploration program can go.
But it's not all gloom and doom: One of NASA's Mars rovers may have given up the ghost, but the other one — Opportunity — has begin its most ambitious adventure yet, exploring the 14-mile-wide Endeavour Crater on Mars. Juno, GRAIL and Mars Science Laboratory were launched toward Jupiter, the moon and Mars, respectively. Other planetary probes are purring along, all the way from Mercury to the solar system's edge.
One of the most promising frontiers for 2012 is being explored by NASA's planet-hunting Kepler spacecraft: The past month has seen the unveiling of Earth-sized planets as well as a Neptune-sized planet sitting in the habitable zone around its parent star. Those alien Earths are still too hot for life, but lots of folks are speculating that we could hear about the first Earth-sized planets in an Earth-type orbit within a year or two.
Which outer-space tales has intrigued you the most over the past year, and what sounds most intriguing for the year ahead? That's what this lineup is all about. I'll list five top stories for 2011, and five top trends for 2012. You can pick your favorite using the Live Vote ballots. Who knows? Your preferences may influence my to-do list for the coming year. Take a run through our "Year in Space Pictures" slideshow to refresh your memory, then cast your vote. We'll crown the winners in an update next week.
Top stories of 2011
It's always tough to limit the list to five, so I'm including an "other" category in this bunch. Please tell me in your comments why you think I'm underplaying or missing your favorite outer-space story.
- NASA ends space shuttle program: Policymakers decided years ago that the shuttle program would have to end once the International Space Station was complete, due to safety and cost concerns. The end finally came in July. Grounding the shuttles theoretically frees up money for exploration programs that go beyond Earth orbit, but in the short term, thousands of jobs are lost. For the time being, NASA has to depend on Russia and other countries for space transport.
- Spirit rover gives up the ghost: After months of trying to re-establish contact with the six-wheeled little trouper, NASA declared that Spirit was really most sincerely dead — felled by stuck wheels and a winter freeze-up. It had a good run: Six years of operation on Mars as part of a mission that was expected to last only 90 days. The Opportunity rover soldiers on, reaching Endeavour Crater after three years of trekking. And it recently made a significant find: gypsum deposits that appear to confirm water once flowed on Mars.
- 'Hubble's successor' dodges a bullet: NASA's James Webb Space Telescope had been in danger of cancellation, but the White House and Congress worked out a deal to keep the project alive on an $8 billion budget. However, the budget negotiations dealt a heavy blow to the White House's request for commercial crew vehicle development, and there are continuing worries about other space science programs, such as the ExoMars missions that NASA is supposed to be working on with the Europeans.
- Earth-sized planets and super-Earths: As I mentioned above, the Kepler science team has been finding a bonanza of planets, including super-hot super-Earths. A parallel effort led by European astronomers is also yielding scores of promising planets. All these discoveries are providing new target lists for colleagues who have been searching for signals from intelligent aliens.
- Downers in Earth orbit: Sometimes the sky seemed to be falling in 2011. In August, an unmanned Soyuz rocket blew up after launch, sparking an investigation that might have led to the evacuation of the International Space Station. NASA's Upper Atmospheric Research Satellite fell to Earth in September, and the German-built ROSAT satellite followed in October. There was lots of hand-wringing over the potential risk from falling debris, but nobody got hurt. The glitch that affected Russia's Phobos-Grunt probe in November will eventually lead to another fall in the new year (see below).
- Other top stories: China tests orbital docking. High-profile love story focuses on congresswoman and astronaut. Alien bacterial claim causes a stir. Asteroid threat downgraded. NASA probes reach Mercury and Vesta. Other spacecraft head for Jupiter and the moon. Auroras put on spectacular shows.
Top trends of 2012
As Yogi Berra supposedly said, "It's tough to make predictions, especially about the future." I'm signaling the speculative nature of the prediction business by sprinkling a few question marks here and there:
- Commercial flights to space station? SpaceX's Dragon cargo craft is currently scheduled to link up with the International Space Station for the first time in February, potentially marking the beginning of a new age in NASA's orbital operations. Orbital Sciences is due to follow later in the year. Meanwhile, commercial ventures will be working on designs for spacecraft capable of putting astronauts in orbit by 2017 or so. How far will NASA's funding get them?
- Monster rover reaches Mars: NASA's November launch of the $2.5 billion Mars Science Laboratory could justifiably rank as one of 2011's top stories, but the real payoff comes in August, when a rocket-powered sky crane is due to drop the 1-ton, car-sized Curiosity rover onto Gale Crater's scientifically intriguing terrain. The big question is: Will that thing really work? But if the rover sets down safely on the surface, we could be in for years of stunning imagery and scientific discovery.
- Earth's twin detected at last? As the Kepler probe takes more observations, Earth-size candidates that lie in Earth-type orbits may well be added to the list of potential planets. Further confirmation would be required to make sure the candidates are truly alien Earths, but even hints that such worlds are on the list could cause a sensation of "Avatar" proportions.
- NASA works on future course: NASA wants to go to an asteroid in the mid-2020s, and send astronauts as far as Mars in the 2030s. But there are lots of blank spaces that still need to be filled in. For example, who'll help NASA build the multibillion-dollar heavy-lift rocket that Congress mandated? What will happen to space science priorities such as Mars sample return and proposed missions to the moons of Jupiter and Saturn? In an era of tightening budgets, how much exploration can NASA afford? Will the presidential election lead to yet another change of vision?
- SpaceShipTwo actually in space? Virgin Galactic's founder, British billionaire Richard Branson, has said powered tests of the company's SpaceShipTwo rocket plane will begin in 2012, and he may well take a ride with his family as a Christmas present next year. If he sticks to that schedule, humans will ride into outer space on a privately developed rocket ship for the first time since SpaceShipOne's trips in 2004. But the tests to date have not been glitch-free, and a question mark is definitely in order.
- Other top stories: Phobos-Grunt plunges in January. Transit of Venus in June. Total solar eclipse in November. Doomsday hype in December. Solar activity rises toward maximum.
There you have it: Click on the links to get more background, weigh the field, and cast your vote. This could be more fun than the Iowa caucus, and I'm saying that as a former Hawkeye. For even more end-of-the-year musings, check out these links:
- Space.com's most memorable spaceflight stories
- Space.com's most amazing astronomy stories
- Space.com: Biggest space flops of the year
- Next steps in the new space race
- 2011: The Year in Space Pictures
- NASA: Year in Review 2011
For something completely different, check out my review of the year's top ancient mysteries.
Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.