Bonneville Crater Bonneville Crater is a nickname given to a feature explored by Spirit. It was inspired by the prehistoric Lake Bonneville that once covered a great portion of modern-day Utah. Image Credit: NASA/JPL/Cornell Link to Full Res

Less than two weeks after Spirit landed on Mars, rover engineers and scientists were already planning Spirit's itinerary on the surface. "Go To That Crater And Turn Right" read the headline of a January 13 press release. Needless to say, generically referring to features as "that crater," "this rock," or "these hills" could quickly become confusing.

"That Crater" was soon named Bonneville Crater. Why? And How? Those are some of the most frequent questions from visitors to NASA's Mars Exploration Rover site.

In Bonneville Crater's case, scientists searching for the record of past water on Mars wanted to see a little bit of Utah on the red planet. Prehistoric Utah, to be precise, when today's Great Salt Lake was once the mega-Lake Bonneville. Geologists can still find signs of its ancient shoreline terracing Utah's mountains and valleys--and hoped to find signs of past water in the martian rock record as well.

	Olympus Mons Olympus Mons, the largest volcano in the solar system, is also known as Nix Olympica, according to international guidelines. Image Credit: NASA/USGS Link to Full Res

International Rules for Naming Features on Mars

"We give names to features near the rovers for convenience," said Dr. Tim Parker, a JPL geologist working on the rover mission. "But it's important to remember they're all unofficial."

The International Astronomical Union (IAU), which fosters international cooperation in astronomy among its member countries and individual scientists, is ultimately responsible for naming land features on planets and their moons. [More on IAU's Naming Process]

In fact, the IAU already has a set of guidelines for names on Mars, explained Parker.

IAU Guidelines for Naming Craters on Mars

Craters less than 100 kilometers (62 miles) in diameter are named after towns on Earth with fewer than 100,000 people. For example, a rural school in New Plymouth, Idaho (population under 1400) submitted their town's name to the IAU. New Plymouth Crater was formally accepted as the official name of a small crater coincidentally near Gusev Crater where Spirit landed.

Craters wider than 100 kilometers are named after late planetary scientists. Using that scheme, a large crater might someday be named after Carl Sagan or Eugene Shoemaker. One has been named after Hal Masursky, a geologist who spent his career at NASA and the US Geological Survey studying lunar and planetary surfaces and the best places for landing.

IAU Guidelines for Naming Mountains and Plains on Mars

Mountains and plains are named after the nearest feature described on the basis of its albedo, or brightness, by the astronomers Schiaparelli, Antoniadi, and others who first began mapping Mars in the 19th and early 20th centuries.

An example is the name Nix Olympica, the classical albedo name, which exists side by side with the geographic name Olympus Mons, used by the U.S. Geological Survey, to designate the largest volcano in the solar system.

That volcano just happens to be covered with snow (nix means snow in Latin) like the famed Mount Olympus of Greek mythology. Both names are official.

Another example is Sinus Meridiani, which means "Middle Bay," applied by the 19th-century astronomer Flammarion to the area where the Opportunity rover landed, on a plain called Meridiani Planum.

Jim Rice Science team member Jim Rice at the rovers' launch pads. Rice suggested naming features according to themes. Image Credit: Dr. James Rice Link to Full Res

Unofficial Feature Names for the Rover Mission

Meanwhile, back at JPL, scientists have devised a system of names that serve as labels for the time being.

After the two robotic rovers landed on Mars in January, Dr. Jim Rice, a geologist at Arizona State University and a rover science team member, suggested that features studied during the mission should be named according to a theme. Principal investigator Dr. Steve Squyres, a geologist at Cornell University, said, "OK, you're in charge."

Rice was the perfect choice for the task. He is practically a walking encyclopedia of interesting historical facts about geological exploration. He also has a friendly way of talking in a deep Southern drawl from his native Alabama that puts other people at ease when they're under pressure to get a thousand things done and are being asked to do just one more thing.

Rice suggested some themes and names and had team members take a vote. They decided to name craters near Spirit's landing site after lakes on Earth and craters near Opportunity's landing site after famous ships of exploration. Rice and Squyres then began assigning names from a list that Rice created.

	Antarctic lake Antarctic lakes such as this one are reminiscent of features on Mars. Image Credit: Dr. James Rice Link to Full Res

Craters Named for Lakes Near Spirit's Landing Site

Naming Bonneville Crater started the trend in naming craters encountered by Spirit for lakes on Earth. Another crater at the Spirit site is named "Turkana," after a lake in the African Rift Valley.

"That's the kind of name I like because that's where anthropologists found the earliest hominid fossils, in the Olduvai Gorge region," said Rice.

"Let's see, then we also had Lake Vanda," said Rice. "That's an ice-covered lake in Antarctica."

Ready to dive Rice prepares to dive into a lake in Antarctica on a geological expedition. Image Credit: Dr. James Rice Link to Full Res

"That was kind of neat," Rice adds, "because both Steve and I have done scuba diving in ice-covered lakes in Antarctica. Opportunity recently discovered that a lake once existed in the Meridiani Planum region. I think that Martian lakes most likely did have ice covers on them."

Also at the Spirit site, there's "Lahontan Crater," after an ancient lake that was once in Nevada and California. On Earth, Lake Lahontan no longer has any water as a result of climate change since the Pleistocene Epoch, when much of North America was covered by ice sheets. Some scientists think that Mars, too, may have undergone climate change and loss of surface water.

	Spirit craters At the Spirit landing site, craters bear the names of lakes on Earth. Image Credit: NASA/JPL/MSSS Link to Full Res

Similarly, "Missoula Crater" was named after glacial Lake Missoula, which occupied portions of present-day Montana and Idaho. Lake Missoula periodically breached its ice dam 13,000 to 15,000 years ago and unleashed a series of catastrophic floods that created the channeled scablands in Washington.

Unofficially, there's now a "Tecopa Crater" on Mars after an ancient lake near Death Valley in California; "Huron Crater" after one of the Great Lakes; and "Baikal Crater" after the world's deepest lake in Russia.

Apollo 11 lunar module Pictured is Buzz Aldrin and the Apollo 11 lunar module, the first ship of exploration to land humans on the moon. Image Credit: NASA Link to Full Res

Famous Ships of Exploration

At the Opportunity site, craters are about the only thing to be seen on an otherwise wind-swept plain. In fact, the rover managed to land in a tiny crater in a vast sea of flatness. That crater was named "Eagle Crater" after the Apollo 11 lunar module that carried Neil Armstrong and Buzz Aldrin to the surface of the moon for the first human lunar landing on July 20, 1969.

	Fram Crater "Fram Crater" was named after a ship used for polar exploration. Image: NASA/ASU/Cornell Link to Full Res

There's also "Fram Crater," named after a ship used by Norwegian explorer Roald Amundsen. Fram means "forward" or "onward" in Norwegian.

"Fram was a famous scientific vessel that conducted an awful lot of important work in the Arctic," said Rice, "but it's most famous for taking Amundsen and his team to Antarctica where he led the first team to reach the South Pole on December 14, 1911."

Opportunity crater names At the Opportunity landing site, craters are named after famous ships of exploration. Image Credit: NASA/JPL/MSSS Link to Full Res

"Endurance Crater," a spectacular crater that features several meters of a layered rock outcrop and debris, was named in honor of the famously ill-fated expedition of Ernest Shackleton to Antarctica aboard the Endurance.

"Endurance is a fitting name because at the time, we were thinking, 'It's going to be a long haul to get there. It's going to test our endurance,'" said Rice. "Plus it was Shackleton's ship."

	Columbia Hills NASA named seven peaks on Mars in honor of the astronauts who perished on the space shuttle Columbia. Image Credit: NASA/JPL/Cornell Link to Full Res

Commemorative, Colorful, and Historical Names

On occasion, the names reflect other human considerations, both serious and fanciful.

Heroes Remembered

NASA Headquarters named the "Columbia Hills," a mile or so from Spirit's landing site, in honor of the lost space shuttle Columbia. Each of the seven peaks bears, at least for now, the last name of one of the Columbia astronauts - Husband, McCool, Anderson, Chawla, Brown, Clark, and Ramon.

Similarly, three hills near the Spirit landing site were named for the three Apollo 1 astronauts Grissom, White, and Chaffee, who died in a flash fire during a dress rehearsal on the launch pad one month before their scheduled launch.

Mazatzal This rock was named "Mazatzal" after a mountain range in Arizona. Image Credit: NASA/JPL/Cornell Link to Full Res

A Travelogue of Place Names

By the time Mars rover team members got around to labeling individual features in the craters, such as individual rocks studied by the rovers, they were no longer following a particular theme. Basically, whoever got to work on analyzing a feature first got to christen it, said Rice.

Many of the nicknames are place names - "Route 66" after the famous interstate highway; "Mazatzal" after a mountain range in Arizona and piece of the North American continent that is more than 1 billion years old; "Guadalupe" and "McKittrick" after mountains in Texas and New Mexico that are famous for fossils, caves, and, in this case, rocks left behind after the evaporation of a shallow sea.

Similarly, there's "Adirondack" (New York), "Tamamend Park" (Pennsylvania), "Camelback" (Arizona), "Stone Mountain" (Georgia), and "Zugspitze" (Germany), to name a few. There's also "Namib" and "Kalahari" after deserts of the same name.

	Endurance Crater Layers in "Endurance Crater" may provide clues to understanding the geologic history of Mars. Image: NASA/JPL/Cornell Link to Full Res

A few of the names are hard to pronounce. John Grotzinger of MIT, a science team member, gave the name "Karatepe" to one of the outcrops in Endurance Crater. It turns out Karatepe (pronounced care-uh-tep-pee) is an archaeological site bearing a bilingual inscription in Phoenician and Hittite. The Phoenician inscription enabled historians to translate Hittite hieroglyphics for the first time. Similarly, the rock outcrop first studied by Opportunity may one day provide "a translation code" for understanding rock layers and climate on Mars overall.

Blueberries Spherules of hematite, nicknamed "blueberries" by scientists, line up with individual layers in rocks on Mars, indicating that they formed in place in wet sediment. Image Credit: NASA/JPL/Cornell Link to Full Res

Rock and Mineral "Flavors": Blueberries and Ice Cream

Often, team members name surface features for objects that they resemble. "Early one Saturday morning back in February, I suggested the name blueberries to describe the hematite-rich spherical particles and it has stuck ever since then," said Rice. The spheres appeared "bluish" due to the camera filter that was used for one of the false-color images.

One day, team members named soil textures after flavors of ice cream. They stocked the martian freezer with names like "Mudpie," "Coconut," "Cookies and Cream," and "Chocolate Chip."

Chocolate Chip refers to the dark, BB-size spherules ("blueberries") of hematite scattered on the Martian surface and perhaps to the fact that team members longed for refreshment during a record-breaking heat wave in Southern California.

	Serpent This rock was nicknamed "Serpent" before it got a set of wheel tracks from one of the Mars rovers. Image Credit: NASA/JPL Link to Full Res

Some Animal References

While the science team hasn't been reminded of many animals in the shapes of rocks, they did nickname one rock "Shark Tooth" given its pointed shape.

They also nicknamed a sand drift "Serpent," which unfortunately later looked something like a smashed serpent where the rover's wheels scuffed the surface to reveal the underlying sediment.

Burns Cliff The name "Burns Cliff," a layered rock outcrop within the impact crater named "Endurance Crater," honors a geologist who foretold the discovery of the mineral jarosite on Mars. Image Credit: NASA/JPL/Cornell Link to Full Res

In a few instances, features are named after people. An example is "Burns Cliff" at Endurance Crater, named after the late Roger Burns, an MIT mineralogist who predicted people might one day find jarosite on Mars. Opportunity actually did find jarosite, an iron sulfate mineral that typically forms when water circulates through and alters iron-rich sediments and rocks. Jarosite was one of the clues that Meridiani Planum was once a water-soaked place.

There's also "Larry's Leap," informally named after science team member Larry Soderblom, a veteran of planetary missions who first suggested taking a rover "toe-dip" (or, wheel dip!) inside Endurance Crater on a relatively shallow slope. (Soderblom, however, did not suggest the name.)

Naming: It's Something Humans Do

Given that none of the names are official and most will probably not survive IAU scrutiny, why bother to give names at all?

As Rice noted: "Whenever explorers go somewhere, we always want to name things. Everybody on this team has named at least one thing, I think it's safe to say, on this mission, one way or the other now. It just makes it more personal. It allows one to leave their little mark on the surface of another planet."

Plus, in a world of technical reports to peers, names have a practical application.

"When I was working at the U.S. Geological Survey in grad school, I was mapping a quadrangle on Mars," said Rice. "When it comes to writing scientific papers, you don't want to keep referring to a crater or other landmarks by their latitude and longitude coordinates. It gets boring and you get tired of writing those coordinates. So you give it a name. It's just something we humans like to do."