This concept art for a 2015 stamp celebrates NASA's New Horizons mission to Pluto.

The next three years just might be prime time for poor little Pluto, thanks to NASA's New Horizons mission — and if the leaders of that mission are successful, a brand-new Pluto postage stamp will be part of the celebration. But they need your help.

Today marks the start of an online petition campaign at Change.org, calling for the creation of a stamp commemorating the $700 million mission and its 2015 Pluto flyby. It would mark only the second time the dwarf planet has appeared on a U.S. postage stamp. The first time was in 1991, when a 29-cent stamp labeled Pluto as "Not Yet Explored."

Back then, some planetary scientists saw that stamp as a challenge — and that gave an early boost to the efforts that eventually led to New Horizons' launch in 2006. The mission's principal investigator, Alan Stern of the Southwest Research Institute, even included one of the old stamps as a pint-sized payload on the spacecraft. Now the postal connection is coming full circle, just in time to render that "Not Yet Explored" label obsolete.

"We're asking people to sign the petition because the post office considers not just the merits of a new stamp proposal, but also whether it is supported by a significant number of people," Stern said in today's kickoff announcement. "This is a chance for us all to celebrate what American space exploration can achieve through hard work, technical excellence, the spirit of scientific inquiry and the uniquely human drive to explore."

USPS

The 1991 stamp was part of a solar-system set.

The petition, along with the formal stamp proposal, would be sent to the U.S. Postal Service's Citizens' Stamp Advisory Committee, which sifts through thousands of suggestions and recommends which subjects should be transformed into commemorative stamps. Last year, for example, one set of stamps paid tribute to Mercury astronaut Alan Shepard's history-making flight in 1961, as well as the Messenger mission to Mercury.

It takes about three years to move from the submission of a proposal to the issuance of a new stamp — which is why Stern and his colleagues are making a big push now for a stamp that would be unveiled in 2015. The more signatures they can get, the better the chances of winning the approval of the committee and the postmaster general.

"If we get 10,000 signatures, we'll get a stamp — that's the impression I get," Stern told me. "But we're aiming for 100,000."

Stern said he'd like to turn in the signatures as well as the stamp proposal during the week of March 13, which marks the 82nd anniversary of the announcement of Pluto's discovery. That's not entirely out of the question, even though the International Astronomical Union reclassified Pluto as a dwarf planet in 2006. After all, how many other celestial bodies have been the subject of letter-writing campaigns, legislative action, street protests and petitions by planetary scientists?

Dan Durda, an artist and space scientist at the Southwest Research Institute whose works appear on the New Horizons website and in many other places (including my book, "The Case for Pluto"), has drawn up a concept for the Pluto stamp — but if the stamp proposal is approved, the stamp's design may well be out of his hands.

"Stamp designing is an unusual art form requiring exacting skill in portraying a subject within very small dimensions," the Postal Service says. "Due to the demands of stamp design and reproduction requirements, it is our policy not to review nor accept unsolicited artwork."

The design isn't uppermost in Stern's mind right now. "You know, I'm sure it will turn out fine," he told me. "Our goal is to commemorate the historic nature of the mission and celebrate U.S. leadership in space exploration. And involve the public."

That's where you come in.

"Sign the petition, and mention it on Facebook," Stern said. "Let's see how high we can drive the numbers for Pluto and for space exploration."

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 or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

M. Showalter / SETI Inst. / NASA / ESA

Hubble imagery from June 28 and July 3 show the changing positions of Pluto's four known moons, including a newly discovered satellite temporarily designated P4.

Astronomers looking for rings around Pluto have instead made an unexpected find: a fourth moon circling the dwarf planet.

The object, temporarily designated P4, is probably the most dwarvish of Pluto's moons: It's estimated to be just 8 to 21 miles (13 to 34 kilometers) in diameter. In comparison, Pluto's diameter is about 1,400 miles, and its other three moons range in diameter from 648 miles (for Charon) to between 20 and 70 miles (for Nix and Hydra, discovered in 2005). The newfound moon orbits in a region between Nix and Hydra, and makes a complete circuit roughly every 31 Earth days.

P4 was detected in June, during a round of Hubble Space Telescope observations aimed at looking for rings or other potential hazards for NASA's New Horizons probe, which is due to zoom through the Pluto system in 2015. Alan Stern, a planetary scientist at the Southwest Regional Institute who heads the $700 million New Horizons mission, told me in an email that the discovery was a testament to the dwarf planet's continuing ability to surprise.

"Pluto's satellite system is truly knocking our socks off with surprises — it's magnificently complex, and getting more crowded all the time. I can't wait till we get there to see what other surprises this planet and its moons have in store for us!" he said.

The find is also a testament to Hubble's amazing vision. The object was spotted on June 28 using the space telescope's Wide Field Camera 3, and its existence was confirmed through follow-up observations this month as well as a search through archived imagery. The moon was not spotted in earlier imagery because the exposure times were shorter.

"I find it remarkable that Hubble's cameras enabled us to see such a tiny object so clearly from a distance of more than 3 billion miles (5 billion km)," Mark Showalter of the California-based SETI Institute, who led the Hubble observing program, said in today's announcement from the Space Telescope Science Institute.

P4 and Pluto's other moons are thought to be the result of a cosmic collision between the dwarf planet and another celestial body early in the solar system's history. Astronomers believe a similar smash-up gave rise to Earth's moon.

Pluto has gotten a bad rap in the past few years, due to its reclassification by the International Astronomical Union in 2006 as a dwarf planet rather than one of the solar system's major planets. Stern sees Pluto as just a different kind of planet rather than an also-ran, and I tend to agree with him. In any case, the fact that the world has a thin atmosphere, changing seasons and more known moons than Mercury, Venus, Earth and Mars combined demonstrates conclusively that you don't have to be one of the big planets to be fascinating. And there may be more to come as New Horizons closes in for its 2015 rendezvous.

"Pluto can retain moons out to almost 100 times the distance of Charon," Stern pointed out.

Update for 10:30 a.m. ET: Although having moons is certainly cool, that doesn't automatically qualify a celestial body to be a planet. A fair number of craggy asteroids possess a moon, or even two. The way the IAU sees it, a "planet" is a roundish celestial body that circles the sun and has "cleared the neighborhood of its orbit," which is widely seen as a deficient definition. A "dwarf planet" is a sun-orbiting celestial body that's big enough to crush itself into a roundish shape, but hasn't cleared out its neighborhood. The way I see it, dwarf planets are planets, too. But I realize a lot of smart folks see it differently. 

Connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. You can also add me to your Google+ circle, and check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

The past decade has brought a whole new frontier of icy worlds to explore on the edge of our solar system — and now you can get in on the exploration as well, through IceHunters.org, the latest citizen-science project from Zooniverse.

Hundreds of thousands of Internet users have signed up for past Zooniverse projects — to classify galaxies, or count lunar craters, or spot solar storms, or identify potential planets orbiting alien stars, based on data from previous astronomical observations. This project is different: For the first time, amateurs can help identify future targets for a NASA interplanetary flyby — in this case, for the New Horizons mission to Pluto and beyond.

Right now, the New Horizons team's top job is getting ready for the 2015 flyby past Pluto and its largest moon, Charon. But the Southwest Research Institute's Alan Stern, principal investigator for the $700 million mission, said he and his colleagues are already looking for follow-up targets in the Kuiper Belt, the wide disk of icy objects beyond the orbit of Neptune. Those targets will have to be selected before the Pluto encounter takes place.

"We'll have four years to find the objects, find the orbits, learn about them and choose the best one or two to fly by," Stern told me today.

Scientists are poring over telescope images to look for the candidates: Kuiper Belt objects, or KBOs, that are smaller than Pluto but still substantial. These icy worlds could reveal more about the origins and the geography of the planetary frontier, but there's only so much that even the professionals can do. The Zooniverse team suggested that citizen scientists could contribute to the cause, and Stern decided that enlisting Internet users would be feasible and fun.

"Maybe a citizen will beat us to the punch," he said.

JHUAPL

An artist's impression shows NASA's New Horizons spacecraft encountering a Kuiper Belt object on the edge of the solar system.

One of the leaders of the IceHunters effort, Pamela Gay, said the project will give a boost to public participation as well as planetary science.

"Projects like this make the public part of modern space exploration," Gay, a professor at Southern Illinois University in Edwardsville, said in a news release. "The New Horizons mission was launched knowing we'd have to discover the object it would visit after Pluto. Now is the time to make that discovery, and thanks to IceHunters, anyone can be that discoverer."

This is no simple task, however: The IceHunters are being asked to check composite images from ground-based telescopes, such as the 8-meter Subaru telescope in Hawaii or the 6.5-meter telescope in Chile, and mark the little blobs that could signal the existence of a Kuiper Belt object.

The technique is a 21st-century version of the method that astronomer Clyde Tombaugh used to discover Pluto 81 years ago. He laboriously checked photographic plates to look for a speck that moved just the right amount of distance in the interval between one exposure and another. IceHunters.org enlists computing power to overlay different images of the same square of sky, and blot out the fixed stars. The little blobs that are left over could be variable stars, or asteroids, or those precious KBOs. It's up to Internet users to check millions of pictures and mark the right blobs for further study.

"Using just about any modern Web browser, users can circle potential KBOs and mark with a star the locations of asteroids," website developer Cory Lehan said in today's SIUE news release. "The website is filled with examples to help get people started. Anyone should be able to take part — no Flash required."

John Spencer, a colleague of Stern's at the Southwest Research Institute and on the New Horizons science team, said the IceHunters' results will be factored into the mission's KBO search effort. "When you're looking for something special in masses of messy, real-world data, sometimes there's no substitute for the human eye, and Zooniverse IceHunters will put thousands of eyes to work on this important job," he said in a New Horizons news release.

New Horizons' scientists will draw up a list of candidate KBOs based on location (Can the spacecraft get to them?) as well as scientific interest (How big are they? What do they seem to be made of? Do they have moons?). The top candidates will be listed online for public review, Stern said.

"I'll make the determination about which objects we fly by, but we're going to ask the public to come in and take a vote. It won't be a binding vote, but there are a great many very talented amateur scientists with a diversity of views, and they can help us," Stern told me.

The New Horizons team will announce one or two targets in the Kuiper Belt shortly before the Pluto flyby in July 2015. The spacecraft will be set on its new course one or two months after that encounter. The KBO observations would likely occur in the 2016-2020 time frame, depending on the distance from Pluto.

There may be an extra payoff for the IceHunters: They just might have a role in the naming of celestial objects that are discovered in the course of the project. Here's what the IceHunters.org FAQ file has to say about that: "In general, astronomers are very fond of catalog numbers, and the variable stars and Kuiper Belt objects you find will all be assigned numbers that are, sadly, quite boring. It may be possible, however, for you to name the asteroids you find — provided you're the first to find them. So start looking, and be the early bird to get the worm asteroid."

More about Pluto and the Kuiper Belt:

• Pluto stays in the spotlight, dead or alive
• The outer solar system remains mysterious
• Scientists find smallest known Pluto sibling
• Interactive: The new solar system
• More about Pluto on Cosmic Log
• More about 'The Case for Pluto'

You can connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. Also, give a look to "The Case for Pluto," my book about the controversial dwarf planet and the Kuiper Belt as well as the search for alien worlds.