NASA MESSENGER: Spacecraft finds Water Ice on Mercury

Kandinsky crater lies near Mercury's north pole, and may have hosted water ice. MESSENGER spacecraft's Wide Angle Camera broadband image appears at left, outlined in yellow, and superimposed on an MDIS polar mosaic.

The view on the right shows the same image but with the brightness and contrast adjusted to show details of the crater's shadowed floor. Image released Oct. 15, 2014.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

The first-ever photos of water ice near Mercury's north pole have come down to Earth, and they have quite a story to tell.

The images, taken by NASA's MESSENGER spacecraft (short for MErcury Surface, Space ENvironment, GEochemistry, and Ranging), suggest that the ice lurking within Mercury's polar craters was delivered recently, and may even be topped up by processes that continue today, researchers said.

More than 20 years ago, Earth-based radar imaging first spotted signs of water ice near Mercury's north and south poles, a surprise, perhaps, given that temperatures on the solar system's innermost planet can top 800 degrees Fahrenheit (427 degrees Celsius).

The left image shows a view of Berlioz crater, with the areas that contain radar-bright material marked in yellow and persistent shadows marked in red. 

The middle image, acquired a few hours later, shows details within the shadowed crater. 

A distinctively darker region sits on the crater's floor, which corresponds well with the radar-bright and shadowed regions as shown in the right image. Image released Oct. 15, 2014.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

In late 2012, MESSENGER confirmed those observations from orbit around Mercury, discovering ice in permanently shadowed craters near the planet's north pole.

MESSENGER scientists announced the find after integrating results from thermal modeling studies with data gathered by the probe's hydrogen-hunting neutron spectrometer and its laser altimeter, which measured the reflectance of the deposits.

And now the MESSENGER team has captured optical-light images of the ice for the first time, by taking advantage of small amounts of sunlight scattered off the craters' walls.

"There is a lot new to be learned by seeing the deposits," said study lead author Nancy Chabot, instrument scientist for MESSENGER’s Mercury Dual Imaging System and a researcher at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, in a statement.

For example, the texture of the ice at the bottom of Mercury's 70-mile-wide (113 kilometers) Prokofiev Crater suggests that the material was put in place relatively recently rather than billions of years ago, researchers said.

Images of other craters back up this notion. They show dark deposits, believed to be frozen organic-rich material, covering ice in some areas, with sharp boundaries between the two different types of material.

"This result was a little surprising, because sharp boundaries indicate that the volatile deposits at Mercury’s poles are geologically young, relative to the time scale for lateral mixing by impacts," Chabot said.

Earth's moon also harbors water ice inside permanently shadowed polar craters, but its deposits look different from those on Mercury, researchers said. This could be because Mercury's ice was delivered more recently.

"If you can understand why one body looks one way and another looks different, you gain insight into the process that's behind it, which in turn is tied to the age and distribution of water ice in the solar system," Chabot said. "This will be a very interesting line of inquiry going forward."

The new study was published online today (Oct. 15) in the journal Geology.

NASA Messenger: Mercury Mission - 10 Years in Space

In celebration of the 10th anniversary of its launch, the MESSENGER team released this movie showing a flyover of Mercury. The movie is sped up by a factor of seven for ease of viewing.

Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory

Ten years ago, on August 3, 2004, NASA’s MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft blasted off from Cape Canaveral, Florida, for a risky mission that would take the small satellite dangerously close to Mercury’s surface, paving the way for an ambitious study of the planet closest to the Sun.

The spacecraft traveled 4.9 billion miles (7.9 billion kilometers), a journey that included 15 trips around the Sun and flybys of Earth once, Venus twice, and Mercury three times, before it was inserted into orbit around its target planet in 2011.

“We have operated successfully in orbit for more than three Earth years and more than 14 Mercury years as we celebrate this amazing 10th anniversary milestone,” said MESSENGER Mission Operations Manager Andy Calloway, of the Johns Hopkins University Applied Physics Laboratory (APL).

“The MESSENGER spacecraft operates in one of the most challenging and demanding space environments in our Solar System, and we have met that challenge directly through innovation and hard work, as exemplified by the stunning discoveries and data return achievements.

Our only regret is that we have insufficient propellant to operate another 10 years, but we look forward to the incredible science returns planned for the final eight months of the mission.”

MESSENGER captured the images in the flyover movie during this flight path over Mercury's north polar region.

Image Credit: NASA

MESSENGER is only the second spacecraft sent to Mercury. Mariner 10 flew past it three times in 1974 and 1975 and gathered detailed data on less than half the surface.

MESSENGER took advantage of an ingenious trajectory design, lightweight materials, and miniaturisation of electronics, all developed in the three decades since Mariner 10 flew past Mercury.

“It was quite challenging to design and execute a trajectory that could culminate in Mercury orbit,” said Mission and Spacecraft Systems Engineer Dan O’Shaughnessy, of APL.

“Designing an attendant spacecraft that was light enough to carry the necessary propellant to execute such a trajectory with enough room left over for a payload capable of global characterisation of the planet is an impressive accomplishment.”

Additionally, he said, “the team’s concept of operations that streamlines planning while optimizing the use of our payload. despite substantial thermal and power constraints, is an amazing feat.”

MESSENGER Deputy Principal Investigator Larry Nittler, of the Carnegie Institution of Washington, said that the mission has rewritten scientists’ understanding of the planet “and given us plenty of surprises.”

“Geochemical measurements have revealed a surface poor in iron, but rich in moderately volatile elements such as sulphur and sodium,” said Nittler.

“These results rule out some long-standing theories put forward to explain Mercury’s anomalously high density compared with the other planets in the inner solar system,” he explained.

“Maps of elemental abundances show that the interior is highly chemically heterogeneous, providing important clues to the early geological history of the planet.”

“MESSENGER observations have also shown that Mercury’s surface was shaped by volcanic activity, identified unique landforms shaped by loss of volatile materials, and confirmed the presence of large amounts of water ice protected from the Sun’s heat within permanently shadowed impact craters near the planet’s poles, said Nittler

Infographic with statistics on the MESSENGER mission.

Image Credit: NASA

“We have found that the complex interplay of the interplanetary magnetic field with that of Mercury results in a remarkably dynamic electromagnetic environment surrounding the planet, including unexplained bursts of electrons and highly variable distributions of different elements in the thin exosphere,” Nittler added.

“Over the next few months, MESSENGER will observe Mercury at lower altitudes and thus smaller spatial scales than ever before, and this is sure to result both in exciting scientific discoveries and new puzzles about our solar system’s enigmatic innermost planet.”

In celebration of the 10th anniversary of its launch, the MESSENGER team has released a movie acquired during an early stage of MESSENGER’s low-altitude campaign.

Messenger narrow-angle camera (NAC)

The movie provides a bird’s-eye view of what the spacecraft sees as it flies over the planet at close range and was assembled from 214 images taken by the narrow-angle camera (NAC) on June 8, 2014.

The NAC’s field of view looked toward the horizon along the direction of MESSENGER's motion as the probe crossed the terminator into night.

Scott Murchie

“This view is what a traveller on the MESSENGER spacecraft might see during low-altitude operations in the coming year,” noted MESSENGER Co-Investigator Scott Murchie of APL.

“During the final phase of its mission, MESSENGER's science instruments will use low-altitude operations like this to explore the surface and subsurface of Mercury at unprecedented resolution.”

The image frames were taken once per second while MESSENGER was at altitudes ranging from 115 to 165 kilometers, traveling at a speed of 3.7 kilometers per second relative to the surface. The movie is sped up by a factor of six for ease of viewing.

Read the full article here

NASA Messenger: Mercury Water Ice Encourages Search for Alien Life

All of the larger polar deposits are located on the floors or walls of impact craters. 

Deposits farther from the pole are seen to be concentrated on the north-facing sides of craters. Image released Nov. 28, 2012. 

CREDIT: NASA/Johns Hopkins University Applied Physics Laboratory/ Carnegie Institution of Washington/ National Astronomy and Ionosphere Center, Arecibo Observatory 

The discovery of huge amounts of water ice and possible organic compounds on the heat-blasted planet Mercury suggests that the raw materials necessary for life as we know it may be common throughout the solar system, researchers say.

Mercury likely harbors between 100 billion and 1 trillion metric tons of water ice in permanently shadowed areas near its poles, scientists analyzing data from NASA's Messenger spacecraft announced Thursday (Nov. 29).

Life on sun-scorched Mercury remains an extreme longshot, the researchers stressed, but the new results should still put a spring in the step of astrobiologists around the world.

"The more we examine the solar system, the more we realize it's a soggy place," Jim Green, the director of NASA's Planetary Science Division, said during a press conference today.

"And that's really quite exciting, because that means the amount of water that we have here on Earth — that was not only inherent when it was originally formed but probably brought here — that water and other volatiles were brought to many other places in the solar system," Green added.

"So it really bodes well for us to continue on the exploration, following the water and its signs throughout the solar system." [Latest Mercury Photos from Messenger]

Scientists Finds Evidence Of Water Ice On Asteroid's Surface

Scientists Finds Evidence Of Water Ice On Asteroid's Surface

This image shows the Themis Main Belt which sits between Mars and Jupiter. Asteroid 24 Themis, one of the largest Main Belt asteroids, was examined by University of Tennessee scientist, Josh Emery, who found water ice and organic material on the asteroid's surface. His findings were published in the April 2010 issue of Nature. Credit: Josh Emery/University of Tennessee, Knoxville.

Asteroids may not be the dark, dry, lifeless chunks of rock scientists have long thought.

Josh Emery, research assistant professor with the earth and planetary sciences department at the University of Tennessee, Knoxville, has found evidence of water ice and organic material on the asteroid 24 Themis. This evidence supports the idea that asteroids could be responsible for bringing water and organic material to Earth.

The findings are detailed in the journal "Nature." Using NASA's Infrared Telescope Facility on Hawaii's Mauna Kea, Emery and Andrew Rivkin of Johns Hopkins University in Laurel, Md., examined the surface of 24 Themis, a 200-kilometer wide asteroid that sits halfway between Mars and Jupiter.

By measuring the spectrum of infrared sunlight reflected by the object, the researchers found the spectrum consistent with frozen water and determined that 24 Themis is coated with a thin film of ice. They also detected organic material.

"The organics we detected appear to be complex, long-chained molecules. Raining down on a barren Earth in meteorites, these could have given a big kick-start to the development of life," Emery said.

Emery noted that finding ice on the surface of 24 Themis was a surprise because the surface is too warm for ice to stick around for a long time.