Trending: Microsoft, Reddit, Twitter, others urge federal court to block Trump’s ‘public charge’ immigration rule
Pluto and Charon
A composite image shows enhanced-color views of Pluto (lower right) and Charon (upper left). Credit: NASA / JHUAPL / SwRI

It’s taken a year and a half, but the International Astronomical Union and the science team behind NASA’s New Horizons mission have finally struck a deal for naming the features on Pluto and its moons.

The agreement, announced today, will open the way for the already well-known “informal” names for places on Pluto, such as Tombaugh Regio and Sputnik Planum, to become formal.

It also allows for features on Charon, Pluto’s biggest moon, to be officially associated with fictional characters and locales – including Mordor from “Lord of the Rings,” Mr. Spock from “Star Trek” and Princess Leia from “Star Wars.”

The scheme is mostly based on names that were suggested even before New Horizons flew past Pluto on July 14, 2015, as part of the SETI Institute’s “Our Pluto” campaign.

The IAU and the New Horizons team agreed on a few tweaks to the categories for Pluto and Charon. For example, the revised scheme allows for naming places on Pluto after pioneering space missions and spacecraft, and naming features on Charon after authors and artists associated with space exploration.

Back in 2015, the IAU wasn’t willing to go along with those themes, because they were similar to themes used for Mercury, Venus and Mars. The revised scheme means that Sputnik Planum – the informal name for the bright left half of Pluto’s “heart” – and Kubrick Mons on Charon are more likely to be OK’d.

Now the New Horizons team will go ahead and submit its dozens of informal names for the IAU’s approval, in accordance with the international body’s longstanding procedures.

Annotatd Pluto map
This annotated map shows the informal names for features on Pluto. Click on the image for a larger version. (Our Pluto / SETI Institute)
This annotated map shows the informal names for features on Charon, Pluto’s largest moon. Click on the image for a larger version. (Our Pluto / SETI Institute)

Some of the scientists on the New Horizons mission, including principal investigator Alan Stern, haven’t always gotten along with the IAU, which engineered the reclassification of Pluto as a dwarf planet in 2006. But today, both sides had good things to say about each other.

Previously: Pluto, we have a problem … some names may not fly on official maps

“I’m very happy with both the process and partnership that New Horizons and the IAU undertook that led to wonderful, inspiring and engaging naming themes for surface features on Pluto and its moons,” Stern said in today’s announcement.

The IAU’s Working Group for Planetary System Nomenclature will work with Stern and his colleagues to sign off on the formal names.

“I am very pleased that the close collaboration of the WGPSN with the New Horizons Team led to these beautiful, inspirational categories for naming the features on Pluto and its satellites,” said Rita Schulz, who’s in charge of the working group. “We are ready now for receiving the proposals for names. Good things take time, but it will be worth it.”

Here are the naming themes that have been approved for Pluto and its moons:


  • Gods, goddesses and other beings associated with the underworld from mythology, folklore and literature
  • Names for the underworld and for underworld locales from mythology, folklore and literature
  • Heroes and other explorers of the underworld
  • Scientists and engineers associated with Pluto and the Kuiper Belt
  • Pioneering space missions and spacecraft
  • Historic pioneers who crossed new horizons in the exploration of the Earth, sea and sky


  • Destinations and milestones of fictional space and other exploration
  • Fictional and mythological vessels of space and other exploration
  • Fictional and mythological voyagers, travelers and explorers
  • Authors and artists associated with space exploration, especially Pluto and the Kuiper Belt

Themes for Pluto’s smaller moons are:

  • Styx: River gods
  • Nix: Deities of the night
  • Kerberos: Dogs from literature, mythology and history
  • Hydra: Legendary serpents and dragons

The agreement means that some of the thousands of names that were suggested and voted on during the “Our Pluto” campaign could soon start appearing on official planetary maps.

“Imagine the thrill of seeing your name suggestion on a future map of Pluto and its moons,” said Jim Green, director of NASA’s Planetary Science Division. “Months after the Pluto flyby, the New Horizons mission continues to engage and inspire.”

New Horizons is now on its way to an encounter in 2019 with yet another icy object in the Kuiper Belt, currently known as 2014 MU69. Someday, that mini-world and its features will have to be given official names as well. Any suggestions?

Subscribe to GeekWire's Space & Science weekly newsletter


Job Listings on GeekWork

Find more jobs on GeekWork. Employers, post a job here.