The Year Ahead in Space: What's Next?

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2015 is the year of the dwarf planets. An artist's concept showing the size of the best known dwarf planets compared to Earth and its moon (top). Eris is left center; Ceres is the small body to its right and Pluto and its moon Charon are at the bottom. NASA

In 2014, the world looked on eagerly as a probe landed on a comet for the first time, as a test flight brought humans one step closer to Mars, and as astronauts tweeted home striking images from space, giving those left behind on Earth the sense that they were along for the ride. And the coming year has plenty more in store.

"2015 is going to be a very exciting year particularly for the public and space exploration," says Bruce Betts, director of science and technology for The Planetary Society. Here are some of the highlights—by no means a comprehensive list—to look forward to in 2015:

The year of the dwarf planets

2015 will be the year of the dwarf planets: Betts says in the coming year, we will see "the first views up close of Pluto and of Ceres, two worlds that humans have been awfully curious about" for many years.

NASA's New Horizons mission is en route for a flyby of Pluto—the once-planet ousted from the category in 2006. And NASA's Dawn mission is scheduled to go into orbit around Ceres in March of 2015. Both Pluto and Ceres are considered "dwarf planets," which are round and orbit the sun like the eight major planets, but are much smaller and have not cleared its orbital path of other objects.

"They're going to worlds the likes of which we've never seen before," says Emily Lakdawalla, science writer and senior editor for The Planetary Society, says of the dwarf planet missions.

Every asteroid we've seen thus far has "looked like a lumpy potato, [but] Ceres is a round world," says Lakdawalla. It's something "in between rocky planets like Mars and Earth and the icy outer planets." It is also the largest object in the asteroid belt.

The New Horizons mission will be approaching its target during the first half of 2015, and is set to zoom past Pluto on July 14, 2015. Throughout the next several months, the spacecraft will be sending back images, and "every week the images will be dramatically better than week before," Alan Stern, the principle investigator for New Horizons, said in a Google hangout about the mission last month.

"Everybody loves Pluto," says Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics. "We're finally going to get a good look at Pluto… the last of the nine planets we grew up with."

Dawn and New Horizons will mark our"first exploration into the real outer solar system," says McDowell. The missions will encounter the "preserved the conditions of the early solar system" up close for the first time, he explains, which could allow scientists to learn about the formation of the solar system.

Seven missions on Mars

During 2015, there will be seven active spacecrafts on Mars, says Lakdawalla, including missions from NASA, the European Space Agency (ESA) and India, which made history in September 2014 when it became the first country to successfully enter the red planet's orbit on its maiden voyage.

"I am sure that 2015 will see a lot more discoveries made on Mars," says Lakdawalla, which "provides us with a window to what ancient Earth might have been like."

Unlike Pluto and Ceres, Mars is not new to scientists. The missions that will run through 2014 will be more about filling out details in our knowledge of the planet, says Betts, seeking answers to questions like: Was there an inhabitable environment on Mars? Why is its atmosphere so thin now?

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This view from the Mast Camera (Mastcam) on NASA's Curiosity Mars rover shows dramatic buttes and layers on the lower flank of Mount Sharp. It is a mosaic of images taken on the 387th Martian day, or sol, of Curiosity's work on Mars (Sept. 7, 2013). NASA/JPL-Caltech/MSSS
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This image of an area on the surface of Mars, approximately 1.5 by 3 kilometers in size, shows frosted gullies on a south-facing slope within a crater. The image was acquired on Nov. 30, 2014, by the High Resolution Imaging Science Experiment (HiRISE) camera, one of six instruments on NASA's Mars Reconnaissance Orbiter. NASA/JPL-Caltech/University of Arizona

Rosetta and Philae

The soft landing of the robotic probe Philae on the surface of Comet 67P/Churyumov- Gerasimenko as part of the Rosetta mission was "the first time anybody's landed on a comet and it's going to be the first time anyone's stayed in orbit as long as Rosetta's going to do," said Science's deputy news editor Robert Coontz.

Last month, Science magazine named the Rosetta mission its breakthrough of the year, emphasizing the fact that the designation was awarded to the entire mission rather than just to Philae's landing.

"Philae got all the spotlight," said Coontz. But much of the work is still to come, and will be performed in the coming year by the mother spacecraft. "We're sort of banking on all the scientific results coming next year." Scientists believe that data collected by Rosetta will help us better understand the formation of Earth and the origins of life on it.

As Rosetta continues to orbit 67P during 2015, the comet will get closer and closer to the sun and throw off more dust and other materials, says Lakdawalla, which Rosetta will sample and study.

Philae—which encountered some trouble on its landing, bouncing twice before settling down sideways in the shadow of a cliff—lost its battery power 57 hours later. It turns out there wasn't enough solar light for it to charge. But, as the comet nears the sun and rotates, the lander should get the solar power it needs to wake up and continue studying the surface of the comet, says McDowell.

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A Rosetta mission poster showing the deployment of the Philae lander to comet 67P/Churyumov–Gerasimenko. The image of the comet was taken with the navigation camera on Rosetta. ESA/Rosetta/NavCam

Humans in space

In March, Scott Kelly will head to the International Space Station on a mission that will make him the first American astronaut to spend a full year in orbit. He'll board a Soyuz spacecraft with his Russian counterpart Mikhail Kornienko, and the two will spend 12 months at the ISS.

"The goal of their year-long expedition aboard the orbiting laboratory is to understand better how the human body reacts and adapts to the harsh environment of space," says NASA.

The mission will mark the longest period an American astronaut has ever spent in space, and it comes with an extra twist straight out of Hollywood. Kelly's twin brother, retired astronaut Mike Kelly, who embarked on four space shuttle flights during his own career, will remain on Earth during the mission so that scientists can use the siblings to learn more the risks of space exploration.

NASA solicited proposals for ways to study "Differential Effects on Homozygous Twin Astronauts Associated with Differences in Exposure to Spaceflight Factors," taking advantage of the rare opportunity to make observations on twins that it says could help understand the effects of spaceflight on the human body.

Not everyone thinks the twin idea is all that great: McDowell calls the plan largely a public relations gimmick, since it would take many more sets of twins to come to any real scientific conclusions.

Private spaceflight

While big government agencies like NASA and the ESA are still at the frontier of space exploration, private companies are finally getting in the game. In 2014, they began running low Earth orbit missions, like those to supply the ISS. Lakdawalla predicts that private companies will continue to work on miniaturization of technology during 2015 and take steps toward getting to the moon.

This Tuesday, for example, SpaceX will run a test launch of its Falcon 9 rocket and will attempt to land it on a floating platform in the Atlantic Ocean, rather than allowing it to splash down into the water as it has on previous tests.

"A fully and rapidly reusable rocket — which has never been done before — is the pivotal breakthrough needed to substantially reduce the cost of space access," SpaceX said in a statement. "While most rockets are designed to burn up on reentry, SpaceX is building rockets that not only withstand reentry, but also land safely on Earth to be refueled and fly again."

Celestial sightings

The year's first meteor shower, visible in the northern hemisphere, took place Saturday night into the wee hours of Sunday morning. However, the bright moon will make it difficult to see the annual Quadrantid shower.

Later in the year, the sky will be dark and moonless for the annual Perseid and Geminid meteor showers, around August 12th and December 13th, respectively, says Alan MacRobert, senior editor of Sky & Telescope Magazine. The meteors are bits of comet debris that "zip into the earth's upper atmosphere at speeds of about 40-60 km per second," or 30-50 miles per second, says MacRobert. "That high speed is what makes them vaporize in a flash of light."

Another highlight in 2015, he says, will be eclipses of the moon on the morning of April 4 and the evening of September 15, two of a series of four eclipses over the course of two years. The first two took place in 2014. During the eclipses, the moon "will glow strong orange or blood red," says MacRobert, reflecting "all of the sunrises and sunsets that are in progress" around the world.

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A "blood moon" is pictured from Gosford, Australia, north of Sydney, on October 8, 2014. Jason Reed/Reuters

Going dark

Space exploration will see a frenzy of activity during 2015 and over the next couple of years, a result of investments made in the 1990s and a slew of launches in the 2000s. "Right now we're riding high on this wave we had from the early 2000s," says Lakdawalla.

But that will soon change. The downsizing of budgets that followed the investments in the 1990s will soon have a visible effect. This year, the inner solar system will go dark for the first time in decades. Contact with the Venus Express spacecraft was lost in November and the Mercury Messenger will crash into Mercury in March or April, says Lakdawalla, more than ten years after it launched.

As for the outer solar system, it is set to go dark in 2017, says Lakdawalla. Because of the massive funding as well as the long planning and preparation periods required for such missions, we are likely to see a gap in active space exploration missions, she adds, probably of roughly a decade. The ESA has a mission in the works for Jupiter, but it is not scheduled to launch until 2022, arriving in 2030.

In other words, the upcoming space events of 2015 are certainly exciting, but they may also mark the end of an era of heightened space exploration.

A feast for the eyes

In the meantime, the coming year will bring striking images back from space. "One of the most wonderful changes that has come to NASA over the last decade is the way they share images with the public," says Lakdawalla, who explains that once upon a time, data would be sent back from missions for use only by scientists, who might publish a paper months later with a smattering of images. "Now the public gets to ride along with these missions."

In addition to images from Rosetta and Pluto, the public can expect to see some spectacular images sent back from Casini at Saturn, whose orbit this year will allow for encounters with Saturn's moons, says Lakdawalla.

"It'll be an exciting space year not just for scientists and engineers but also for the public," says Betts. "There'll be a lot of easily consumable [material and images], from eclipses to exploring a new world."

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Although solid-looking in many images, Saturn's rings are actually translucent. This image was taken with the Cassini spacecraft wide-angle camera on Aug. 12, 2014. NASA/JPL-Caltech/Space Science Institute