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Space News Update — November 20, 2015 —

Contents

In the News

Story 1: Mars rover steers toward active sand dunes

Story 2: The Origin of Massive Stars

Story 3: NASA's STEREO-A resumes normal operations

Departments

The Night Sky

ISS Sighting Opportunities

Space Calendar

NASA-TV Highlights

Food for Thought

Space Image of the Week

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1. Mars rover steers toward active sand dunes

The Curiosity rover’s next destination is a moving mound of wind-blown dark sand blanketing the base of Mount Sharp, the focal point of the Mars mission’s research, scientists said this week.

It will take a few days to reach the dunes, and rover drivers at NASA’s Jet Propulsion Laboratory must be careful to avoid guiding Curiosity too far into the dune field and getting stuck.

A similar predicament ended the mission of the Spirit rover, Curiosity’s predecessor on the red planet, when it drove into a much smaller sand trap in 2009. Engineers were never able to free the rover from the sand pit, and the craft’s solar panels were pointed in the wrong direction to collect energy from the sun as it fell low on the horizon in the Martian winter.

Curiosity will not have the same pitfall as Spirit because it relies on a nuclear power source, but an entangled rover would threaten the future of the mission, which is in its fourth year.

Curiosity will be the first rover to explore an active Martian sand dune up close. The rover is heading for a stretch of sand dunes called the “Bagnold Dunes” named for Ralph Bagnold, a British military engineer who pioneered research into how winds transport sand grains in the early 20th century.

One of the dunes is as tall as a two-story building and as broad as a football field, according to a NASA press release.

Images from a sharp-eyed camera aboard NASA’s Mars Reconnaissance Orbiter show the dunes are moving up to 3 feet, or 1 meter, per year, scientists said.

As of Monday, Curiosity was about 200 meters, or 660 feet, from the dune it is heading to first. The rover has completed further drives this week.

“The Bagnold Dunes are tantalizingly close, and this week is mostly focused on driving to the dunes. On Sol 1167 (overnight Tuesday, U.S. time), Curiosity drove 39 meters (128 feet), and the dunes are starting to look pretty big,” wrote Lauren Edgar, a research geologist with the U.S. Geological Survey and a member of the Curiosity science team, in a blog post Wednesday.

Once Curiosity reaches the dunes, scientists plan to use the rover’s robot arm to scoop a sample of sand for delivery to the craft’s internal laboratory instruments. The rover will also use a wheel to dig into the dune to reveal its interior, according to NASA.

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Curiosity is slowly trekking up the foothills of Mount Sharp, a three-mile-high peak inside Gale Crater, a basin excavated by an asteroid or comet impact.

The dune campaign is a natural extension of Curiosity’s primary focus of studying ancient geological processes that shaped rocks and made the red planet habitable billions of years ago, scientists said.

“We’ve planned investigations that will not only tell us about modern dune activity on Mars but will also help us interpret the composition of sandstone layers made from dunes that turned into rock long ago,” said Bethany Ehlmann, a scientist at the California Institute of Technology and JPL.

The water flows and volcanism that carved giant channels and built towering mountains on Mars in ancient times are no more. Winds are now the most significant cause of Martian erosion, scientists said.

Wind measurements to prepare for the dune campaign have already begun. Geologists hope to learn how much of a role wind played in forming ancient sedimentary rocks like sandstone compared to the effects of water in transporting sediments.

“We will use Curiosity to learn whether the wind is actually sorting the minerals in the dunes by how the wind transports particles of different grain size,” Ehlmann said in a NASA press release.

Researchers believe dunes on Mars behave differently than they do on Earth. The surface pressure on Mars is about six-tenths of one percent the pressure on Earth, with Martian gravity three times weaker than Earth’s.

“These dunes have a different texture from dunes on Earth,” said Nathan Bridges from the Johns Hopkins University’s Applied Physics Laboratory, who leads dune campaign planning with Ehlmann. “The ripples on them are much larger than ripples on top of dunes on Earth, and we don’t know why. We have models based on the lower air pressure. It takes a higher wind speed to get a particle moving. But now we’ll have the first opportunity to make detailed observations.”

Source: Spaceflight Now Return to Contents

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2. The Origin of Massive Stars

There’s a reason astronomers call the Sun a dwarf. Though about 1,000 Jupiters could fit inside our star, it’s a tame pipsqueak compared with the rare and massive O and B stars that end their lives in fantastic supernova explosions. Recent evidence, though, shows that all stars may form in much the same way. Despite their divergent ends, could it be that such different stars claim the same provenance?

That question has proven difficult to answer. Astronomers have long known that low-mass stars form stepwise: a cloud collapses into clumps, clumps collapse into cores, then cores collapse into disks that each feed their own central protostar. But massive stars have kept their origin stories a secret: they’re rare, far away, and form so quickly that they’re born still swaddled in the dust and gas that smaller stars shed.

Now, new observations from the Atacama Large Millimeter/submillimeter Array (ALMA) and Atacama Pathfinder Experiment (APEX) in Chile have enabled astronomers to peer through a cocoon and see a stable disk of gas feeding the forming O-star at its center. Katharine Johnston (University of Leeds, UK) and colleagues published their results in the November 1st Astrophysical Journal.

A Massive Star with a Disk

Johnston’s team observed a protostar, dubbed AFGL 4176, with ALMA at wavelengths around 1.2 millimeters. Though the star-to-be lies 14,000 light-years away, 36 of ALMA’s antennas separated by up to 1.2 kilometers captured the system at 0.3-arcsecond resolution.

The sharp, long-wavelength images pierce the dust cocoon and reveal the motions of gas swirling in a disk that feeds the central protostar. The disk spans somewhere between 760 and 980 times the Earth-Sun distance — several times the size of our own solar system.

Lower-resolution observations with APEX also show outflows shooting out from both sides of the structure. Since accretion disks of all kinds, whether around stars or black holes, generally sport jets or winds, this observation supports the disk scenario.

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Other Stars & Other "Disks"

This find isn’t totally unprecedented, says Andrés Guzmán (University of Chile and Harvard-Smithsonian Center for Astrophysics). For example, in 2014 Guzmán led a team that found a rotating structure around the future O star G345.4938+01.4677. But this structure might not be a "real" disk — that is, a stable object whose physics is managed by the massive protostar at its center. It might instead be a gravitationally unstable donut-shaped mass that could perhaps even collapse to form a second star in orbit around the first.

Other observations, such as that of Álvaro Sánchez-Monge (then at Astrophysical Observatory of Arcetri, Italy) and colleagues, found a more stable structure around the future B-type star G35.20+0.74N.

However, Guzmán says, the new observations from Johnston's team are “better and more clear in many ways,” thanks in part to improvements on ALMA, including the addition of antennas and the ability to separate antennas by longer distances.

“High-mass stars are becoming more and more clearly associated with disks,” Guzmán adds. “Now we need to determine whether these disks play the same role in high-mass star formation as in low-mass protostars.” In other words, do massive stars grow from their disks in the same way as their smaller brethren? Will planets around massive stars form in the same way as well? With ALMA only growing in its millimeter-observing power, astronomers may soon answer these questions.

Source: Sky & Telescope Return to Contents

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3. NASA's STEREO-A resumes normal operations

On Nov. 9, 2015, NASA's Solar and Terrestrial Relations Observatory Ahead, or STEREO-A, once again began transmitting data at its full rate. For the previous year, STEREO-A was transmitting only a weak signal--or occasionally none at all--due to its position almost directly behind the sun. Subsequently, as of Nov. 17, STEREO resumed its normal science operations, which includes transmission of lower-resolution real-time data--used by scientists to monitor solar events--as well as high-definition, but delayed, images of the sun's surface and atmosphere.

One of the key components of the real-time data, known as beacon data, is what's called coronagraph imagery - in which the bright light of the sun is blocked out in order to better see the sun's faint atmosphere. Coronagraphs are key for monitoring when the sun erupts with a coronal mass ejection, which can send a giant cloud of solar material out into space. Such space weather can lead to interference with radio

communications, GPS signals and satellites.

"STEREO-A's real-time data is key for scientists to make accurate models of interplanetary space weather," said Yari Collado-Vega, a space scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Having a second set of coronagraph images, in addition to those from the Solar and Heliospheric Observatory (SOHO), means we can measure coronal mass ejections much more accurately."

For the past year, however, beacon data was only received for a few hours each day--if at all--limiting scientists' ability to monitor the sun. Since August 2014, our line of communication to the spacecraft was so close to the sun that pointing the antenna straight at Earth also meant pointing it nearly directly at the sun, which would cause the spacecraft's antenna to dangerously overheat. Now that STEREO-A has emerged from behind the sun, scientists have once again pointed the main lobe of STEREO-A's antenna towards Earth and the stronger signal means that the majority of the beacon data can once again be picked up.

STEREO-A is also using this stronger signal to send high-definition views of the sun's far side with a two- to three-day delay. These detailed images of the sun's surface and atmosphere allow scientists to better track the formation of solar events.

"We're now using STEREO-A to its fullest capabilities, given how far away it is," said Terry Kucera, deputy project scientist for the STEREO mission at Goddard.

STEREO-A's twin spacecraft, STEREO Behind, has been out of communication since October 2014, when communications were lost following a planned reset of the spacecraft. For several months, STEREO-B's orbit took it behind the sun from our perspective, making it impossible to send messages to the spacecraft. But STEREO-B will soon emerge from the sun's interference zone, and spacecraft operators will resume their attempts to contact the spacecraft on Nov. 30.

Source: Eureka Alert Return to Contents

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The Night Sky Friday, November 20

• Before dawn tomorrow morning, look east for bright Jupiter and brighter Venus. Between them is little orange Mars. Look carefully; very close to Mars is the 4th-magnitude star Eta Virginis. The two may appear less than 0.1° apart depending on where you are.

• If Mars seems to be awfully slow to brighten as it moves higher in the dawn this season, that's because it's at the aphelion of its orbit, its farthest from the Sun — exactly so today.

Saturday, November 21

• After dark these nights, Altair is the brightest star in the west-southwest. Look upper left of it, by barely more than a fist at arm's length, for the delicate little constellation Delphinus, the Dolphin. To Altair's upper right by a lesser distance is little Sagitta, the Arrow.

Sunday, November 22

• Whenever Fomalhaut is "southing" (crossing the meridian due south, which it does around 7 p.m. now depending on your location), the first stars of Orion are just about to rise in the east, and the Pointers of the Big Dipper stand vertical straight below Polaris, due north.

Monday, November 23

• Look above or upper left of the gibbous Moon this evening for the two leading stars of Aries. Farther left of the Moon is the Pleiades cluster with Aldebaran down below it. Much farther left shines bright Capella.

The full Moon shines in the Hyades near Aldebaran (for North America) the night before Thanksgiving. (The Moon is drawn three times its actual apparent size.)

Tuesday, November 24

• The almost-full Moon this evening shines not quite midway between the Pleiades to its left and Alpha Ceti (orange-tinted Menkar) to its right. Menkar is well off the edge of the scene here.

• Algol is at minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 10:15 p.m. EST (per new predictions).

Source: Sky & Telescope Return to Contents

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ISS Sighting Opportunities

For Denver:

Date Visible Max Height Appears Disappears

Sat Nov 21, 4:45 AM 1 min 15° 15° above NNE 10° above NE

Sat Nov 21, 6:18 AM 4 min 73° 10° above NW 44° above ESE

Sun Nov 22, 5:26 AM 3 min 38° 25° above NNW 25° above E

Mon Nov 23, 4:35 AM < 1 min 18° 18° above ENE 14° above ENE

Mon Nov 23, 6:08 AM 5 min 43° 12° above WNW 13° above SSE

Tue Nov 24, 5:17 AM 2 min 86° 61° above NW 23° above SE

Sighting information for other cities can be found at NASA’s Satellite Sighting Information

NASA-TV Highlights (all times Eastern Daylight Time)

3 p.m., Monday, November 23 - Replay of the ISS Expedition 46-47 Crew News Conference at Star City, Russia (all channels)

3:30 p.m., Monday, November 23 - Replay of the ISS Expedition 46-47 Crew’s Ceremonial Visit to the Gagarin Museum in Star City, Russia and their Visit to Red Square and the Kremlin in Moscow (Starts at 3:45 p.m.) (all channels)

6:30 a.m., Tuesday, November 24 - Video B-Roll of ISS Expedition 46-47 NASA Astronaut Tim Kopra’s Training (all channels)

7 a.m., Tuesday, November 24 - Live Interviews with ISS Expedition 46-47 NASA Astronaut Tim Kopra from Star City, Russia (all channels)

Watch NASA TV on the Net by going to the NASA website. Return to Contents

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Space Calendar • Nov 20 - Comet C/2015 GX (PANSTARRS) Closest Approach To Earth (1.462 AU) • Nov 20 - Comet 147P/Kushida-Muramatsu At Opposition (1.812) • Nov 20 - Asteroid 192 Nausikaa At Opposition (8.4 Magnitude) • Nov 20 - Aten Asteroid 413577 (2005 UL5) Near-Earth Flyby (0.015 AU)

• Nov 20 - [Nov 20] Apollo Asteroid 2015 WC1 Near-Earth Flyby (0.025 AU)

• Nov 20 - [Nov 18] Apollo Asteroid 2015 VV142 Near-Earth Flyby (0.039 AU) • Nov 20 - Apollo Asteroid 29075 (1950 DA) Closest Approach To Earth (1.533 AU) • Nov 20 - Asteroid 4749 Ledzepplin Closest Approach To Earth (1.781 AU) • Nov 20 - Lecture: Human Colonisation of Mars, London, United Kingdom • Nov 21 - Comet 74P/Smirnova-Chernykh Closest Approach To Earth (3.291 AU) • Nov 21 - Comet C/2015 A2 (PANSTARRS) At Opposition (4.338 AU) • Nov 21 - Apollo Asteroid 2015 VE66 Near-Earth Flyby (0.019 AU) • Nov 21 - Asteroid 7010 Locke Closest Approach To Earth (1.013 AU) • Nov 21 - Asteroid 1991 Darwin Closest Approach To Earth (1.358 AU) • Nov 21 - Asteroid 8734 Warner Closest Approach To Earth (1.762 AU) • Nov 21 - Asteroid 6442 Salzburg Closest Approach To Earth (1.790 AU) • Nov 21 - Griffith Observatory Star Party, Los Angeles, California • Nov 21 - 80th Anniversary (1935), Great Meteor Shower of 1935 • Nov 21 - 90th Anniversary (1925), Great Meteor Shower of 1925 • Nov 22 - Moon Occults Uranus • Nov 22 - Comet 147P/Kushida-Muramatsu Closest Approach To Earth (1.811) • Nov 22 - Comet 308P/Lagerkvist-Carsenty Closest Approach To Earth (3.357 AU) • Nov 22 - Asteroid 2002 Euler Closest Approach To Earth (1.608 AU) • Nov 22 - Asteroid 5471 Tunguska Closest Approach To Earth (2.176 AU) • Nov 22 - Owen Garriott's 85th Birthday (1930) • Nov 22 - Jerrie Mock's 90th Birthday (1925) • Nov 22 - Karl Bruhns' 185th Birthday (1830) • Nov 23 - Cassini, Distant Flyby of Tethys • Nov 23 - Comet P/2014 V1 (PANSTARRS) At Opposition (2.344 AU) • Nov 23 - Comet 125P/Spacewatch At Opposition (3.759 AU) • Nov 23 - Asteroid 35137 Meudon Closest Approach To Earth (1.748 AU) • Nov 23 - Asteroid 2906 Caltech Closest Approach To Earth (1.936 AU) • Nov 23 - Asteroid 3131 Mason-Dixon Closest Approach To Earth (2.021 AU) • Nov 23 - Phobos and Deimos Webcast: Space Weathering and Regolith, DusSpace Weathering and Regolith, Dust • Nov 23 - 55th Anniversary (1960), Tiros II Launch (Weather Satellite) • Nov 23 - Vladislav Volkov's 80th Birthday (1935) • Nov 24 - Telstar 12V H-2A Launch • Nov 24 - Cassini, Distant Flyby of Atlas, Daphins & Methone • Nov 24 - Comet 315P/LONEOS Closest Approach To Earth (2.716 AU)

• Nov 24 - [Nov 18] Comet C/2015 V3 (PANSTARRS) Perihelion (4.239 AU) • Nov 24 - Asteroid 269 Justitia Occults HIP 29704 (5.3 Magnitude Star)

• Nov 24 - [Nov 17] Apollo Asteroid 2015 VO142 Near-Earth Flyby (0.003 AU) • Nov 24 - Amor Asteroid 2015 VH2 Near-Earth Flyby (0.033 AU) • Nov 24 - Apollo Asteroid 2015 RQ82 Near-Earth Flyby (0.074 AU) • Nov 24 - Amor Asteroid 2011 YS62 Near-Earth Flyby (0.092 AU) • Nov 24 - Asteroid 9620 Ericidle Closest Approach To Earth (0.927 AU) • Nov 24 - Asteroid 3831 Pettengill Closest Approach To Earth (1.392 AU) • Nov 24 - Asteroid 243 Ida Closest Approach To Earth (1.759 AU) • Nov 24 - John Brashear's 175th Birthday (1840)

Source: JPL Space Calendar Return to Contents

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Food for Thought

'Chemical Laptop' Could Search for Signs of Life Outside Earth

If you were looking for the signatures of life on another world, you would want to take something small and portable with you. That's the philosophy behind the "Chemical Laptop" being developed at NASA's Jet Propulsion Laboratory in Pasadena, California: a miniaturized laboratory that analyzes samples for materials associated with life.

"If this instrument were to be sent to space, it would be the most sensitive device of its kind to leave Earth, and the first to be able to look for both amino acids and fatty acids," said Jessica Creamer, a NASA postdoctoral fellow based at JPL.

Like a tricorder from "Star Trek," the Chemical Laptop is a miniaturized on-the-go laboratory, which researchers hope to send one day to another planetary body such as Mars or Europa. It is roughly the size of a regular computing laptop, but much thicker to make room for chemical analysis components inside. But unlike a tricorder, it has to ingest a sample to analyze it.

"Our device is a chemical analyzer that can be reprogrammed like a laptop to perform different functions," said Fernanda Mora, a JPL technologist who is developing the instrument with JPL's Peter Willis, the project's principal investigator. "As on a regular laptop, we have different apps for different analyses like amino acids and fatty acids."

Amino acids are building blocks of proteins, while fatty acids are key components of cell membranes. Both are essential to life, but can also be found in non-life sources. The Chemical Laptop may be able to tell the difference.

What it's looking for

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Amino acids come in two types: Left-handed and right-handed. Like the left and right hands of a person, these amino acids are mirror images of each other but contain the same components. Some scientists hypothesize that life on Earth evolved to use just left-handed amino acids because that standard was adopted early in life's history, sort of like the way VHS became the standard for video instead of Betamax in the 1980s. It's possible that life on other worlds might use the right-handed kind.

"If a test found a 50-50 mixture of left-handed and right-handed amino acids, we could conclude that the sample was probably not of biological origin," Creamer said. "But if we were to find an excess of either left or right, that would be the golden ticket. That would be the best evidence so far that life exists on other planets."

The analysis of amino acids is particularly challenging because the left- and right-handed versions are equal in size and electric charge. Even more challenging is developing a method that can look for all the amino acids in a single analysis.

When the laptop is set to look for fatty acids, scientists are most interested in the length of the acids' carbon chain. This is an indication of what organisms are or were present.

How it works

The battery-powered Chemical Laptop needs a liquid sample to analyze, which is more difficult to obtain on a planetary body such as Mars. The group collaborated with JPL's Luther Beegle to incorporate an "espresso machine" technology, in which the sample is put into a tube with liquid water and heated to above 212 degrees Fahrenheit (100 degrees Celsius). The water then comes out carrying the organic molecules with it. The Sample Analysis at Mars (SAM) instrument suite on NASA's Mars Curiosity rover utilizes a similar principle, but it uses heat without water.

Once the water sample is fed into the Chemical Laptop, the device prepares the sample by mixing it with a fluorescent dye, which attaches the dye to the amino acids or fatty acids. The sample then flows into a microchip inside the device, where the amino acids or fatty acids can be separated from one another. At the end of the separation channel is a detection laser. The dye allows researchers see a signal corresponding to the amino acids or fatty acids when they pass the laser.

Inside a "separation channel" of the microchip, there are already chemical additives that mix with the sample. Some of these species will only interact with right-handed amino acids, and some will only interact with the left-handed variety. These additives will change the relative amount of time the left and right-handed amino acids are in the separation channel, allowing scientists to determine the "handedness" of amino acids in the sample.

Testing for future uses

Last year the researchers did a field test at JPL's Mars Yard, where they placed the Chemical Laptop on a test rover.

"This was the first time we showed the instrument works outside of the laboratory setting. This is the first step toward demonstrating a totally portable and automated instrument that can operate in the field," said Mora.

For this test, the laptop analyzed a sample of "green rust," a mineral that absorbs organic molecules in its layers and may be significant in the origin of life, said JPL's Michael Russell, who helped provide the sample.

"One ultimate goal is to put a detector like this on a spacecraft such as a Mars rover, so for our first test outside the lab we literally did that," said Willis.

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Since then, Mora has been working to improve the sensitivity of the Chemical Laptop so it can detect even smaller amounts of amino acids or fatty acids. Currently, the instrument can detect concentrations as low as parts per trillion. Mora is currently testing a new laser and detector technology.

Coming up is a test in the Atacama Desert in Chile, with collaboration from NASA's Ames Research Center, Moffett Field, California, through a grant from NASA's Planetary Science & Technology Through Analog Research (PSTAR) program.

"This could also be an especially useful tool for icy-worlds targets such as Enceladus and Europa. All you would need to do is melt a little bit of the ice, and you could sample it and analyze it directly," Creamer said.

The Chemical Laptop technology has applications for Earth, too. It could be used for environmental monitoring -- analyzing samples directly in the field, rather than taking them back to a laboratory. Uses for medicine could include testing whether the contents of drugs are legitimate or counterfeit.

Creamer recently won an award for her work in this area at JPL's Postdoc Research Day Poster Session.

Source: Spaceflight Now Return to Contents

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Space Image(s) of the Week

A Day on Pluto, a Day on Charon

Pluto’s day is 6.4 Earth days long. The images were taken by the Long Range Reconnaissance Imager (LORRI) and the Ralph/Multispectral Visible Imaging Camera as the distance between New Horizons and Pluto decreased from 5 million miles (8 million kilometers) on July 7 to 400,000 miles (about 645,000 kilometers) on July 13. The more distant images contribute to the view at the 3 o’clock position, with the top of the heart-shaped, informally named Tombaugh Regio slipping out of view, giving way to the side of Pluto that was facing away from New Horizons during closest approach on July 14. The side New Horizons saw in most detail – what the mission team calls the “encounter hemisphere” – is at the 6 o’clock position.

These images and others like them reveal many details about Pluto, including the differences between the encounter hemisphere and the so-called “far side” hemisphere seen only at lower resolution. Dimples in the

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bottom (south) edge of Pluto’s disk are artifacts of the way the images were combined to create these composites.

Charon – like Pluto – rotates once every 6.4 Earth days. The photos were taken by the Long Range Reconnaissance Imager (LORRI) and the Ralph/Multispectral Visible Imaging Camera from July 7-13, as New Horizons closed in over a range of 6.4 million miles (10.2 million kilometers). The more distant images contribute to the view at the 9 o’clock position, with few of the signature surface features visible, such as the cratered uplands, canyons, or rolling plains of the informally named Vulcan Planum. The side New Horizons saw in most detail, during closest approach on July 14, 2015, is at the 12 o’clock position.

These images and others like them reveal many details about Charon, including how similar looking the encounter hemisphere is to the so-called “far side” hemisphere seen only at low resolution – which is the opposite of the situation at Pluto. Dimples in the bottom (south) edge of Charon’s disk are artifacts of the way the New Horizons images were combined to create these composites.

Source: NASA Return to Contents