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Space News Update — August 1, 2014 —

Contents

In the News

Story 1:

NASA selects instruments for Mars 2020 rover

Story 2:

Early Tidal and Rotational Forces Helped Shape Moon

Story 3:

Mysterious Molecules in Space Named?

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. NASA selects instruments for Mars 2020 rover

NASA's next Mars rover will feature state-of-the-art science and technology instruments, including a device to cache rock and soil samples for possible return to Earth and another to extract oxygen from the martian atmosphere, testing technology that could help future astronauts "live off the land" to some extent, officials said Thursday. Modeled after NASA's hugely successful Curiosity rover now operating on the red planet's surface, the Mars 2020 rover will weigh roughly the same, about one ton, feature the same nuclear power pack and use the same "sky crane" entry, descent and landing system. While it will look almost identical to Curiosity, the Mars 2020 rover is expected to cost about $1.9 billion, some $600 million less than Curiosity thanks to the common design and left over spare parts, and it will feature a different suite of instruments.

"This rover's going to carry new, innovative instruments like we've never seen before on Mars to conduct geological investigations on the surface to determine potential habitability, but also to look for potential signs of past life in the geological record," said John Grunsfeld, director of space science at NASA Headquarters. Of 58 proposals submitted from around the world, NASA selected seven, announcing the winners during a news conference at agency headquarters. The compact intruments will weigh about 90 pounds altogether and cost some $130 million to develop. Along with searching for "biosignatures" in the martian rocks and soil it studies, the 2020 rover will be on the lookout for particularly interesting samples that might warrant more detailed analysis on Earth. While the details are still being considered, the 2020 rover is expected to be equipped with a caching system to store small samples in sealed tubes that could be retrieved by a future robotic spacecraft. Or an astronaut.

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"As you might imagine, we're still early on in the mission design and how exactly the cache is going to be is still being worked out," said Michael Meyer, lead scientist with NASA's Mars exploration program. "The expectation is it will be on the rover, the samples will be cached and then there is some debate whether or not we drop the cache and the rover goes off and does its own thing somewhere else, or whether or not it just stays with the rover the whole time," he said. A third option is to drop some of the cached samples off at some point during the mission and to keep other samples with the rover. Like Curiosity, the 2020 rover will be equipped with an imaging mast carrying a pair of "souped up" cameras. One, called Mastcam-Z, will be capable of panoramic and stereo imaging, providing the same sort of perspective an astronaut might have standing on the surface. The "Z" refers to the camera's ability to zoom, something Curiosity's cameras cannot do. Grunsfeld said the new camera will "knock our socks off." "You're going to feel like you're on Mars," he said. "It's going to be fantastic." A second mast-mounted camera system is known as SuperCam. Similar to the ChemCam instrument aboard Curiosity, SuperCam will be able to vaporize rock samples with a powerful laser and study the components blasted away for analysis of chemical composition and mineralogy, including remote detection of organic compounds. A body-mounted instrument known as PIXL, for "Planetary Instrument for X-ray Lithochemistry," will use an X-ray fluorescence spectrometer to map out chemical elements in targeted samples with greater detail than ever before. Another instrument known as SHERLOC will be built around an ultraviolet laser spectrometer designed to study mineralogy and search for organic compounds. A Spanish weather station will measure temperature, wind speed and direction, pressure and humidity, along with studying the dust suspended in the martian atmosphere. And in a first for Mars exploration, the 2020 rover will be equipped with a ground-penetrating radar capable of detecting geologic structures three tenths of a mile down. The seventh instrument in the 2020 rover's scientific arsenal is the Mars Oxygen ISRU Experiment, or MOXIE, designed to extract oxygen from the carbon dioxide making up the thin martian atmosphere. "It's not so much we're going to actually use the oxygen, but can we actually generate the oxygen, what kind of rates can we generate it at, what kind of efficiency can we do?" said Bill Gerstenmaier, NASA's director of space operations. Being able to generate oxygen in situ, and possibly water and even rocket fuel at some point in the future, "really changes the dynamics" of possible crewed missions to Mars, Gerstenmaier said. "If you can get propellant, or get oxidizer, for your ascent stage to come off of Mars and you don't have to carry that with you, that really changes your mission design," he said. "If you can actually cache and put oxygen in storage tanks before the crew even arrives and you know they have a habitable environment and a place to go when they get there, that's tremendously important to us. "This will buy down the uncertainty of that it will make sure we understand the risks associated with that."

Source: CBS News “Space Place” Return to Contents

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2. Early Tidal and Rotational Forces Helped Shape Moon

The shape of the moon deviates from a simple sphere in a way that scientists have struggled to explain. But new research shows that tidal forces during the moon’s early history can explain most of its large-scale topography. As the moon cooled and solidified more than four billion years ago, the sculpting effects of tidal and rotational forces became frozen in place.

Astronomers think the moon formed when a rogue planet, larger than Mars, struck the Earth in a great, glancing blow. A cloud rose 13,700 miles (22,000 kilometers) above the Earth, where it condensed into innumerable solid particles that orbited the Earth. Over time these moonlets combined to form the moon.

So the moon was sculpted by Earth’s gravity from the get-go. Although scientists have long postulated that tidal forces helped shape the molten moon, the new study provides a much more detailed understanding of the additional forces at play.

Ian Garrick-Bethell from UCSC and colleagues studied topographic data gathered by NASA’s Lunar Reconnaissance Orbiter (LRO) and information about the moon’s gravity field collected by the agency’s twin GRAIL (Gravity Recovery and Interior Laboratory) spacecraft.

Not long after the moon’s formation, the crust was decoupled from the mantle below by an intervening ocean of magma. This caused immense tidal forces. At the poles, where the flexing and heating was greatest, the crust became thinner, while the thickest crust formed at the equators. Garrick-Bethel likened this to a lemon shape with the long axis of the lemon pointing at the Earth.

But this process does not explain why the bulge is now only found on the far side of the moon. You would expect to see it on both sides, because tides have a symmetrical effect.

“In 2010, we found one area that fits the tidal heating effect, but that study left open the rest of the moon and didn’t include the tidal-rotational deformation. In this paper we tried to bring all those considerations together,” said Garrick-Bethell in a press release.

Any rotational forces would cause the spinning moon to flatten slightly at the poles and bulge out near the equator. It would have had a similar effect on the moon’s shape as the tidal heating did — both of which left distinct signatures in the moon’s gravity field. Because the crust is lighter than the underlying mantle, gravity signals reveal variations in the moon’s internal structure, many of which may be due to previous forces.

Interestingly, Garrick-Bethell and colleagues discovered that the moon’s overall gravity field is no longer aligned with the topography. The long axis of the moon doesn’t point directly toward Earth as it likely did when the moon first formed; instead, it’s offset by about 30 degrees.

“The moon that faced us a long time ago has shifted, so we’re no longer looking at the primordial face of the moon,” said Garrick-Bethell. “Changes in the mass distribution shifted the orientation of the moon. The craters removed some mass, and there were also internal changes, probably related to when the moon became volcanically active.”

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The details and timing of these processes are still uncertain, but the new analysis should help shed light on the tidal and rotational forces abundant throughout the Solar System and the Galaxy. These simple forces, after all, have helped shape our nearest neighbor and the most distant exoplanet.

The results have been published today in Nature.

Source: Universe Today Return to Contents

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3. Mysterious Molecules in Space Named?

It’s a well-kept secret that the vacuum of space is not — technically speaking — a vacuum. Strong winds generated from supernova explosions push material into the interstellar medium, tainting space with the heavier elements generated by nuclear fusion. These lonely molecules account for a significant amount of all the hydrogen, carbon, silicon, and other atoms in the Universe. Although these molecules remain mysterious, since we don’t know their exact chemical composition or atomic arrangements, they’re likely the cause of diffuse interstellar bands: unknown fingerprints within the spectra of distant astronomical objects.

New research, however, offers a tantalizing new possibility: these mysterious molecules may be silicon hydrocarbons.

Researchers on Earth should be able to identify the interstellar molecules easily. They simply have to demonstrate which molecules in the laboratory absorb light at the same wavelengths as the diffuse interstellar bands. But despite decades of effort, the identity of the molecules has remained a mystery.

“Not a single one has been definitively assigned to a specific molecule,” said coauthor Neil Reilly from the Harvard-Smithsonian Center for Astrophysics in a press release.

Now, Michael McCarthy from the Harvard-Smithsonian Center for Astrophysics, Reilly, and their colleagues are pointing to an unusual set of molecules — silicon-terminated carbon chain radicals such as SiC3H, SiC4H and SC5H — as potential twins to those found in interstellar space.

The researchers, however, were unable to create every spectral absorption line (over 400) responsible for the diffuse interstellar bands. But they think that longer molecules in this silicon-containing hydrocarbon family might cause the lines.

So the group remains cautious. History shows that while many possibilities have been proposed as the source of diffuse interstellar bands, none have been proven definitely. And they certainly need to conduct further research before they can say with certainty they’ve identified the mysterious interstellar molecules.

“The interstellar medium is a fascinating environment,” said McCarthy. “Many of the things that are quite abundant there are really unknown on Earth.”

Source: Universe Today Return to Contents

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The Night Sky

Source: Sky & Telescope Return to Contents

Friday, August 1 At dusk this evening, the Moon forms the lower-right end of a very long, curving line of celestial objects. Counting to the Moon's upper left, these are Spica, Mars, and Saturn, as shown here. Today is Lammas Day or Lughnasadh, one of the four traditional "cross-quarter" days midway between the solstices and equinoxes. More or less. The actual midpoint between the June solstice and the September equinox this year comes at 2:40 a.m. August 7th Eastern Daylight Time (6:40 UT). That will be the exact center of (astronomical) summer. Saturday, August 2 The Moon shines about midway between Spica and Mars this evening, as shown here. Sunday, August 3 The first-quarter Moon shines between Mars and Saturn as seen from the Americas and Europe, as shown above (plotted for the middle of North America). The Moon will occult (cover) Saturn as seen from Australia, where the local date will be August 4th. Watch live via Slooh starting at 11:00 UT August 4th (7 a.m. August 4th Eastern Daylight Time in the US). Monday, August 4 Now the Moon forms the left end of a ragged line with Saturn, Mars, and Spica to its right. To the Moon's lower left are the vertical row of stars forming the head of Scorpius (highlighted by Delta Scorpii, labeled below), and then Antares. Tuesday, August 5 Look below the Moon this evening for the red supergiant Antares, as shown at right. Around Antares and to its right are other stars of upper Scorpius.

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ISS Sighting Opportunities

For Denver:

Date Visible Max Height Appears Disappears

Fri Aug 1, 10:23 PM < 1 min 10° 10 above SW 10 above SW

Sat Aug 2, 3:17 AM 5 min 18° 10 above NNW 10 above ENE

Sat Aug 2, 4:53 AM 6 min 84° 10 above NW 12 above SE

Sat Aug 2, 9:34 PM 6 min 47° 11 above SSW 11 above ENE

Sat Aug 2, 11:12 PM 2 min 23° 11 above W 23 above NNW

Sun Aug 3, 2:28 AM 3 min 14° 11 above NNW 10 above NE

Sun Aug 3, 4:04 AM 6 min 54° 10 above NW 11 above ESE

Sun Aug 3, 8:46 PM 5 min 25° 11 above S 11 above ENE

Sun Aug 3, 10:23 PM 6 min 34° 12 above W 11 above NE

Mon Aug 4, 3:18 AM 3 min 33° 33 above NNE 10 above E

Mon Aug 4, 4:52 AM 5 min 27° 11 above WNW 11 above SSE

Mon Aug 4, 9:33 PM 6 min 57° 10 above WSW 11 above NE

Mon Aug 4, 11:14 PM 2 min 14° 14 above NNW 10 above NNE

Tue Aug 5, 8:44 PM 6 min 79° 10 above SW 11 above NE

Tue Aug 5, 10:25 PM 2 min 18° 18 above NNW 10 above NNE

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

NASA-TV Highlights (all times Eastern Daylight Time)

1 p.m., Friday, August 1 - Replay of NASA Mars 2020 Rover Payload Announcement (all channels)

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

Return to Contents

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Space Calendar

Aug 01 - [Jul 31] GPS 2F-7 Atlas 5 Launch Aug 01 - Alpha Capricornids Meteor Shower Peak Aug 01 - Comet P/1999 XN120 (Catalina) At Opposition (3.740 AU) Aug 01 - Comet 144P/Kushida At Opposition (4.325 AU) Aug 01 - Asteroid 2014 OG1 Near-Earth Flyby (0.068 AU) Aug 01 - Asteroid 3949 Mach Closest Approach To Earth (1.225 AU) Aug 01 - Asteroid 7462 Grenoble Closest Approach To Earth (1.457 AU) Aug 01 - Asteroid 9357 Venezuela Closest Approach To Earth (1.837 AU) Aug 01 - Asteroid 3352 McAuliffe Closest Approach To Earth (2.199 AU) Aug 02 - Mercury Passes 1.0 Degrees From Jupiter Aug 02 - Comet P/2008 QP20 (LINEAR-Hill) Closest Approach To Earth (1.952 AU) Aug 02 - Comet 263P/Gibbs At Opposition (3.737 AU) Aug 02 - Asteroid 2554 Skiff Closest Approach To Earth (0.993 AU) Aug 02 - Asteroid 69230 Hermes Closest Approach To Earth (1.594 AU) Aug 02 - Asteroid 3115 Baily Closest Approach To Earth (1.740 AU) Aug 02 - Asteroid 189202 Calar Alto Closest Approach To Earth (2.057 AU) Aug 03 - Rosetta, Trajectory Correction Maneuver

Aug 03 - [Jul 29] Comet P/2014 MG4 (Spacewatch-PANSTARRS) At Opposition (3.134 AU) Aug 03 - Asteroid 17033 Rusty Closest Approach To Earth (1.162 AU) Aug 03 - Asteroid 1000 Piazzia Closest Approach To Earth (1.752 AU) Aug 04 - AsiaSat 8 Falcon 9 Launch Aug 04 - Moon Occults Saturn Aug 04 - Comet 282P/2003 BM80 At Opposition (3.022 AU) Aug 04 - Comet 118P/Shoemaker-Levy At Opposition (3.294 AU) Aug 04 - Asteroid 80 Sappho At Opposition (9.9 Magnitude) Aug 04 - Asteroid 9134 Encke Closest Approach To Earth (1.798 AU)

Aug 04 - [Jul 30] Europa Pre-Proposal Teleconference, Aug 05 - Comet 193P/LINEAR-NEAT Closest Approach To Earth (1.320 AU) Aug 05 - Asteroid 83360 Catalina Closest Approach To Earth (1.292 AU) Aug 05 - Asteroid 30444 Shemp Closest Approach To Earth (1.350 AU) Aug 05 - Asteroid 7032 Hitchcock Closest Approach To Earth (1.435 AU) Aug 05 - Asteroid 6442 Salzburg Closest Approach To Earth (1.585 AU) Aug 05 - 45th Anniversary (1969), Mariner 7 Mars Flyby

Source: JPL Space Calendar Return to Contents

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Food for Thought

Earth’s Shadow Creeps Up on Us Every Night

Here's a riddle. What sets when the Sun rises and rises when the Sun sets?

If you guessed Earth's shadow, give yourself a pat on the back. Strangely, it might be the most common but widely ignored phenomenon of the twilight sky.

I suspect most people have seen the purple-gray band of shadow that grows along the eastern horizon after sunset on clear evenings but dismissed it as clouds or haze. In one sense, the shadow resembles an approaching storm, a dark presence rising in the east that slowly overtakes the fading blue twilight until overtaken itself by night.

To see a shadow it must be cast on something. When it comes to a whole planet, the only thing big enough close to home is the atmosphere itself. Find a location with a wide open to the east at sunset (or west starting about 30 minutes before sunrise) and look for a blue-gray band rimming the horizon directly opposite the sunset. Sweep your gaze along the nearly 180° arc for a visceral feel of Earth's true girth.

A delicate rosy glow called the Belt of Venus caps the shadow along its length. Although we might never know who first coined the term, it likely refers to the alluring, magical breast band worn by that famous Greek goddess. Also known as the anti-twilight arch, it's formed when reddened sunlight is scattered back to our eyes by air higher up still touched by the low Sun.

A few minutes may suffice to appreciate our planet's form hanging in thin air, but spend 20 minutes and you'll see the full story unfold.

When the Sun is just 2° below the horizon (about 8 to 10 minutes after sunset) the shadow hovers low along the eastern horizon. Because our gaze penetrates the hazy air of the lower atmosphere nearly edge-on at this time, the edge of the shadow is more distinct. This is also when the Belt of Venus is brightest and most colorful.

By the time the Sun dips to –5°, not only has the shadow climbed steadily higher, it's grown more diffuse and the belt has begun to fade. Some 25 minutes after sunset, the shadow blends into the deepening blue of twilight and disappears.

Sometimes you'll see a crown of blue and pink beams converging atop the rising shadow. These are anti-crepuscular rays. Their cousins, crepuscular rays, form when sunbeams shine through gaps in towering clouds to create a spreading fan of sunbeams and shadows. Under the right conditions, patchy clouds below the

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observer's sunset horizon can create crepuscular rays that extend all the way to the opposite end of the sky as anti-crepuscular rays. Watch for them.

If you want to see Earth's shadow at its most dramatic, get a window seat on your next airplane flight. Last month, by pure luck I ended up sitting on the left side of the plane as we flew southwest over the sunset hour. Seen from the clean, dry air at 35,000 feet, the shadow appeared ominously dark purple with a much sharper edge than ground dwellers are accustomed to seeing.

Part of the enhanced contrast undoubtedly came from seeing the shadow edge-on with all the haze and aerosols in the lower atmosphere stacked across a vast horizontal distance — perfect for shadow-casting! But I wonder if the raw transparency of rarefied air at high altitude may also have been a factor. If you've never seen our planet's shadow from an airplane, plan your seating well. Or get lucky. Either way you'll be wowed.

Source: Sky & Telescope Return to Contents

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Space Image of the Week

Comet 67P from 1,200 Miles Away

Less than a week before Rosetta's rendezvous with comet 67P/Churyumov-Gerasimenko, images obtained by OSIRIS, the spacecraft's onboard scientific imaging system, show clear signs of a coma surrounding the comet's nucleus. A new image from July 25, 2014, clearly reveals an extended coma shrouding 67P's nucleus. "Our coma images cover an area of 150 by 150 square kilometers (90 by 90 square miles)," said Luisa Lara from the Institute of Astrophysics in Andalusia, Spain. Most likely these images show only the inner part of the coma, where particle densities are highest. Scientist expect that 67P's full coma actually reaches much farther. In the current image, the hazy, bright, circular structure to the right of the comet's nucleus is an artifact of the OSIRIS optical system. The center of the image located around the position of the nucleus is overexposed here. One pixel in this image corresponds to approximately 120 feet (37 meters). Source: NASA Return to Contents