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Space News Update — January 2, 2015 —

Contents

In the News

Story 1:

Dawn begins final approach to dwarf planet Ceres

Story 2:

Finding Lovejoy: How to Follow the Path of Comet 2014 Q2 Through January

Story 3:

Technology Innovations Spin NASA's SMAP into Space

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. Dawn begins final approach to dwarf planet Ceres

NASA’s Dawn spacecraft has begun its final approach to the dwarf planet Ceres, the largest object in the

asteroid belt, for an in-depth survey of the uncharted world.

The solar-powered space probe is scheduled to arrive at Ceres in March, when the Texas-sized world’s gravity

will capture Dawn in orbit. With the help of its electrically-powered ion propulsion system, Dawn will reach a circular orbit 8,400 miles from Ceres by late April.

Seven years into its mission, Dawn is on an interplanetary sojourn to visit two of the solar system’s most

massive asteroids. After launching from Earth in September 2007, Dawn orbited asteroid Vesta from July 2011 to September 2012, when it started a nearly three-year journey to Ceres.

Dawn will become the first spacecraft to orbit two extraterrestrial objects when it arrives at Ceres in March.

Such a journey would not be possible without Dawn’s three ion engines, which combine electrical power and

xenon gas to generate modest levels of thrust.

Conventional thrusters fueled by chemical propellants provide a greater push, but ion thrusters are more

efficient. By firing the less powerful ion thrusters for months at a time, Dawn is reshaping its trajectory through the solar system in ways chemically-powered spacecraft could not achieve.

Dawn’s ion thrusting was interrupted for four days in September when the probe was blasted by a high-energy particle of cosmic radiation, temporarily knocking the propulsion system offline.

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Interplanetary navigators based at NASA’s Jet Propulsion Laboratory plotted a new course for Dawn to reach Ceres on almost the same schedule as planned before the craft was hit by a blitz of cosmic rays.

Under the new plan, Dawn will be snared by the gravitational tug of Ceres on March 6. But instead of Ceres pulling the probe directly into orbit 8,400 miles from the dwarf planet, Dawn will fly out in front of Ceres

before its gravity — working together with continued thrusting from Dawn’s ion engines — gently captures the spacecraft.

The maneuver will be done without the need for a large conventional rocket burn performed on missions

arriving at Mars or other planets.

By April 23, Dawn will be in its initial 8,400-mile-high orbit around Ceres, according to a blog post by Marc

Rayman, the mission’s chief engineer.

As of Dec. 29, Dawn was about 400,000 miles from Ceres and closing in at around 450 mph, according to a

JPL press release.

Dawn will survey Ceres from a series of different altitudes, measuring the world’s composition, internal

structure, and surface characteristics.

Scientists believe Ceres formed like the rest of the solar system’s planets, but it failed to collect enough

material to build up size. It measures nearly 600 miles across and has a spherical shape, according to imagery of Ceres taken by the Hubble Space Telescope.

Ceres is very different from Vesta — Dawn’s first destination — which is rocky, covered in ancient impact

craters, and has an irregular shape. Scientists say Ceres is covered in ice and may even harbor and underground ocean of liquid water.

But the full picture of Ceres will not be known until Dawn’s arrival. By the end of January, Dawn’s camera will begin taking better images of Ceres than possible with Hubble.

“Ceres is almost a complete mystery to us,” said Christopher Russell, principal investigator for the Dawn mission from the University of California, Los Angeles. “Ceres, unlike Vesta, has no meteorites linked to it to

help reveal its secrets. All we can predict with confidence is that we will be surprised.”

Source: Spaceflight Now Return to Contents

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2. Finding Lovejoy: How to Follow the Path of Comet 2014 Q2 Through January

Have you seen the amazing pics? A bright comet graces evening skies this month, assuring that 2015 is already on

track to be a great year for astronomy. We’re talking about Comet C/2014 Q2 Lovejoy. Discovered

by comet hunter extraordinaire Terry Lovejoy on August 17th, 2014, this denizen of the Oort Cloud has already wowed observers as it approaches its passage perihelion

through the inner solar system in the coming week. First, our story thus far. We’ve been following all Comet

Q2 Lovejoy action pretty closely here at Universe Today, from its surreptitious brighteningahead of schedule, to its recent tail disconnection event, to its photogenic

passage past the +8.6 magnitude globular cluster Messier 79 (M79) in the constellation Lepus. We also continue to be routinely blown away byreader

photos of the comet. And, like the Hare for which Lepus is named, Q2 Lovejoy is now racing rapidly northward, passing into the rambling constellation of Eridanus the River before entering the realm of Taurus the Bull on January 9th and later crossing the ecliptic plane in Aries.

And the best window of opportunity for spying the comet is coming right up. We recently caught our first sight of Q2 Lovejoy a few evenings ago with our trusty Canon 15x 45 image-stabilized binocs from Mapleton, Maine. Even as seen from latitude 47 degrees north and a frosty -23 Celsius (-10 Fahrenheit) — a far cry from our

usual Florida based perspective — the comet was an easy catch as a bright fuzz ball. Q2 Lovejoy was just outside of naked eye visibility for us this week, though I suspect that this will change as the Moon moves out of the evening picture this weekend.

Currently shining at magnitude +5.5, Comet Q2 Lovejoy has already been spied by eagle-eyed observers unaided from dark sky sites to the south. Astrophotographers have revealed its long majestic dust and ion

tails, as well as the greenish hue characteristic of bright comets. That green color isn’t kryptonite, but the fluorescing of diatomic carbon and cyanogen gas shed by the comet as it’s struck by ultraviolet sunlight. This greenish color is far more apparent in photographs, though it might just be glimpsed visually if the intrinsic

brightness of the coma exceeds expectations. Q2 Lovejoy just passed opposition at 0.48 AU from the Earth today on January 2nd, and will make its closest passage from our fair world on January 7th at 0.47 AU (43.6 million kilometres) distant.

What’s so special about the coming week? Well, we also cross a key milestone for evening observing, as the light-polluting Moon reaches Full phase on Sunday January 5th at 4:54 UT (11:54 PM EDT on the 4th) and

begins sliding out of the evening sky on successive evenings. That’s good news, as Comet Q2 Lovejoy enters the “prime time” evening sky and culminates over the southern horizon at around 10:30 PM local this weekend, then 8:00 PM on January the 15th, and just before 6:00 PM by January 31st.

While many comets put on difficult to observe dusk or dawn appearances — the 2013 apparition of another comet, C/2011 L4 PanSTARRS comes to mind — Q2 Lovejoy is well placed this month in the early evening hours.

The current projected peak brightness for Comet Q2 Lovejoy is +4th magnitude right around mid-January. Already, the comet is bright enough and well-placed to the south for northern hemisphere observers that it’s

possible to catch astrophotos of the comet along with foreground objects. If you’ve got a tripod mounted DSLR give it a try… it’s as simple as aiming, focusing manually with a wide field of view, and taking 10 to 30 second exposures to see what turns up. Longer shots will call for sky tracking via a barn-door or motorized

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mount. Binoculars are you friend in your comet-hunting quest, as they can be readily deployed in sub-zero January temps and provide a generous field of view.

Q2 Lovejoy will also pass near the open clusters of the Hyades and the Pleiades through mid-January, and cross into the constellations of Aries and Triangulum by late January before heading northward to pass between the famous Double Cluster in Perseus and the Andromeda Galaxy M31 in February, proving further

photo ops. From there, Q2 Lovejoy is expected to drop below naked eye visibility in late February before passing very

near the North Star Polaris and the northern celestial pole at the end of May on its way out of the inner solar system on its 8,000 year journey.

So, although 2014 didn’t produce the touted “comet of the century,” 2015 is already getting off to a pretty good start in terms of comets. We’re out looking nearly every clear night, and the next “big one” could always drop by at anytime… but hopefully, the first discovery baring the name “Comet Dickinson” will merely put on a

spectacular show, and not prove to be an extinction level event…

Source: Universe Today Return to Contents

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3. Technology Innovations Spin NASA's SMAP into Space

It's active. It's passive. And it's got a big, spinning lasso.

Scheduled for launch on Jan. 29, 2015, NASA's Soil Moisture Active Passive (SMAP) instrument will measure the moisture lodged in Earth's soils with an unprecedented accuracy and resolution. The instrument's three main parts are a radar, a radiometer and the largest rotating mesh antenna ever deployed in space.

Remote sensing instruments are called "active" when they emit their own signals and "passive" when they record signals that already exist. The mission's science instrument ropes together a sensor of each type to

corral the highest-resolution, most accurate measurements ever made of soil moisture -- a tiny fraction of Earth's water that has a disproportionately large effect on weather and agriculture.

To enable the mission to meet its accuracy needs while covering the globe every three days or less, SMAP engineers at NASA's Jet Propulsion Laboratory in Pasadena, California, designed and built the largest rotating antenna that could be stowed into a space of only one foot by four feet (30 by 120 centimeters) for launch.

The dish is 19.7 feet (6 meters) in diameter.

"We call it the spinning lasso," said Wendy Edelstein of NASA's Jet Propulsion Laboratory, Pasadena, California,

the SMAP instrument manager. Like the cowboy's lariat, the antenna is attached on one side to an arm with a crook in its elbow. It spins around the arm at about 14 revolutions per minute (one complete rotation every four seconds). The antenna dish was provided by Northrop Grumman Astro Aerospace in Carpinteria,

California. The motor that spins the antenna was provided by the Boeing Company in El Segundo, California.

"The antenna caused us a lot of angst, no doubt about it," Edelstein noted. Although the antenna must fit during launch into a space not much bigger than a tall kitchen trash can, it must unfold so precisely that the

surface shape of the mesh is accurate within about an eighth of an inch (a few millimeters).

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The mesh dish is edged with a ring of lightweight graphite supports that stretch apart like a baby gate when a single cable is pulled, drawing the mesh outward. "Making sure we don't have snags, that the mesh doesn't

hang up on the supports and tear when it's deploying -- all of that requires very careful engineering," Edelstein said. "We test, and we test, and we test some more. We have a very stable and robust system now."

SMAP's radar, developed and built at JPL, uses the antenna to transmit microwaves toward Earth and receive the signals that bounce back, called backscatter. The microwaves penetrate a few inches or more into the soil before they rebound. Changes in the electrical properties of the returning microwaves indicate changes in soil

moisture, and also tell whether or not the soil is frozen. Using a complex technique called synthetic aperture radar processing, the radar can produce ultra-sharp images with a resolution of about half a mile to a mile and a half (one to three kilometers).

SMAP's radiometer detects differences in Earth's natural emissions of microwaves that are caused by water in soil. To address a problem that has seriously hampered earlier missions using this kind of instrument to study

soil moisture, the radiometer designers at NASA's Goddard Space Flight Center, Greenbelt, Maryland, developed and built one of the most sophisticated signal-processing systems ever created for such a scientific instrument.

The problem is radio frequency interference. The microwave wavelengths that SMAP uses are officially reserved for scientific use, but signals at nearby wavelengths that are used for air traffic control, cell phones and other purposes spill over into SMAP's wavelengths unpredictably. Conventional signal processing averages

data over a long time period, which means that even a short burst of interference skews the record for that whole period. The Goddard engineers devised a new way to delete only the small segments of actual interference, leaving much more of the observations untouched.

Combining the radar and radiometer signals allows scientists to take advantage of the strengths of both technologies while working around their weaknesses. "The radiometer provides more accurate soil moisture

but a coarse resolution of about 40 kilometers [25 miles] across," said JPL's Eni Njoku, a research scientist with SMAP. "With the radar, you can create very high resolution, but it's less accurate. To get both an accurate and a high-resolution measurement, we process the two signals together."

SMAP will be the fifth NASA Earth science mission launched within the last 12 months.

For more about the SMAP mission, visit: http://www.nasa.gov/smap/

Source: JPL Return to Contents

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The Night Sky

Source: Sky & Telescope Return to Contents

Friday, January 2 This evening the Moon shines among some of the sky's brightest relatively cool stars. Look for orange-

red Aldebaran (spectral type K5 III) to the Moon's upper right, similarly tinted Betelgeuse (type M2 Iab) farther below the Moon, and orange Pollux (type K0

III) much farther to the Moon's lower left. Hotter Capella, yellow-white and type G5 III, shines high to the Moon's upper left.

Saturday, January 3 Are you tracking Venus and Mercury yet? They're

just 2½° apart now, low in the afterglow of sunset in the southwest as shown here. Brilliant Venus is on top. They're drawing closer together and will appear

closest, just 0.6° apart, a week from today. Sunday, January 4 Tonight the eclipsing variable star Algol should be at

minimum light, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 12:07 a.m. EST. Algol takes several additional hours to fade and to

rebrighten. Monday, January 5

Sirius and Procyon in the balance: Sirius, the Dog Star, sparkles low in the east-southeast after dinnertime. Procyon, the Little Dog Star, shines in

the east about two fist-widths at arm's length to Sirius's left. If you live around latitude 30° north (Tijuana, New Orleans, Jacksonville), the two canine

stars will be at the same height above your horizon soon after they rise. If you're north of that latitude, Procyon will be higher. If you're south of there, Sirius

will be the higher one. Tuesday, January 6

Watch for Jupiter and then Regulus to rise lower left of the Moon. They're well up by 9 p.m., as shown here.

In early evening at this time of year, the Great Square of Pegasus balances on one corner high in the west. The vast Andromeda-Pegasus constellation

complex runs all the way from near the zenith (Andromeda's foot) down through the Great Square (Pegasus's body) almost to the western horizon (Pegasus's nose).

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ISS Sighting Opportunities

For Denver:

Date Visible Max Height Appears Disappears

Mon Jan 5, 6:16 AM 2 min 17° 10 above S 17 above SE

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

NASA-TV Highlights (all times Eastern Daylight Time)

12 p.m., Monday, January 5 - NASA ISS Earth Science Briefing: Cloud Aerosol Transport System

(CATS) (all channels)

1:30 p.m., Monday, January 5 - NASA ISS Research and Technology Briefing (all channels) 4 p.m., Monday, January 5 - SpaceX Commercial Resupply Services (CRS) -5 Prelaunch News

Conference (all channels)

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

Return to Contents

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Space Calendar

Jan 02 - Comet C/2014 Q2 (Lovejoy) At Opposition (0.488 AU)

Jan 02 - Comet C/2014 F2 (Tenagra) Perihelion (4.314 AU)

Jan 02 - Comet C/2014 W3 (PANSTARRS) Closest Approach To Earth (5.476 AU)

Jan 02 - Asteroid 4245 Nairc Occults HIP 19009 (5.5 Magnitude Star)

Jan 02 - Asteroid 2005 YQ96 Near-Earth Flyby (0.026 AU)

Jan 02 - Asteroid 18725 Atacama Closest Approach To Earth (1.445 AU)

Jan 02 - Asteroid 1981 Midas Closest Approach To Earth (2.210 AU)

Jan 02 - Isaac Asimov's 95th Birthday (1920)

Jan 02 - Leslie Peltier's 115th Birthday (1900)

Jan 03 - Quadrantids Meteor Shower Peak

Jan 03 - Comet 268P/Bernardi Closest Approach To Earth (1.618 AU)

Jan 03 - Comet 271P/van Houten-Lemmon Closest Approach To Earth (4.086 AU)

Jan 03 - [Jan 02] Asteroid 2014 YE42 Near-Earth Flyby (0.011 AU)

Jan 03 - [Dec 30] Asteroid 2014 YQ34 Near-Earth Flyby (0.079 AU)

Jan 03 - Asteroid 241418 Darmstadt Closest Approach To Earth (2.019 AU)

Jan 03 - 15th Annivesary (2000), Galileo, Europa 26 Flyby

Jan 03 - 45th Anniversary (1970), Lost City Meteorite Fall (Hit House in Oklahoma)

Jan 04 - Earth At Perihelion (0.983 AU From Sun)

Jan 04 - Comet 37P/Forbes At Opposition (4.313 AU)

Jan 04 - [Dec 30] Asteroid 2014 YP34 Near-Earth Flyby (0.022 AU)

Jan 04 - [Jan 01] Asteroid 2014 YB42 Near-Earth Flyby (0.043 AU)

Jan 04 - Asteroid 9725 Wainscoat Closest Approach To Earth (1.834 AU)

Jan 04 - Asteroid 13681 Monty Python Closest Approach To Earth (2.212 AU)

Jan 05 - Mercury Passes 1.7 Degrees From Venus

Jan 05 - Comet P/2005 T2 (Christensen) At Opposition (3.821 AU)

Jan 05 - Asteroid 85990 (1999 JV6) Near-Earth Flyby (0.083 AU)

Jan 05 - 10th Anniversary (2005), Mike Brown, et al's Discovery of Dwarf Planet Eris

Jan 05 - 110th Anniversary (1905), Charles Perrine's Discovery of Jupiter Moon Elara

Jan 06 - [Dec 30] CRS-5 Cloud-Aerosol Transport System (CATS)/ AggieSat 4/ Bevo

2/ SERPENS Falcon 9R Launch (International Space Station)

Jan 06 - Comet 116P/Wild Closest Approach To Earth (2.233 AU)

Jan 06 - Comet 180P/NEAT Closest Approach To Earth (2.259 AU)

Jan 06 - Comet C/2014 Q6 (PANSTARRS) Perihelion (4.223 AU)

Jan 06 - Asteroid 6592 Goya Closest Approach To Earth (1.463 AU)

Jan 06 - Asteroid 3752 Camillo Closest Approach To Earth (1.711 AU)

Jan 06 - Asteroid 13752 Grantstokes Closest Approach To Earth (1.824 AU)

Jan 06 - Asteroid 2329 Orthos Closest Approach To Earth (2.594 AU)

Jan 06 - 30th Anniversary (1985), La Criolla Meteorite Fall (Hit House in Argentina)

Jan 06 - [Jan 01] Liisi Oterma's 100th Birthday (1915)

Jan 06 - Jacques Etienne Montgolfier's 270th Birthday (1745)

Jan 06 - Jacob Bernoulli's 360th Birthday (1655)

Source: JPL Space Calendar Return to Contents

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Food for Thought

What Makes Moonlight Special?

A moonlit stroll is starkly different from a walk in the sunshine. Moonlight's dark, spooky quality contrasts with the clarity of sunlight. And while it may not grow hair on

your face, we can't help but notice the blacker shadows, blurred details, and lack of color in the landscape on a moonlit night.

We peer into the gloom straining to see what's there, but lacking the usual visual cues, we're liable to fill in the

darkness with our imagination. Is that Bigfoot up ahead or the neighbor's garbage can?

For these reasons, it's often used in scary movies where exaggerated contrasts under studio moonlight create an unfamiliar landscape where anything can happen,

including romance.

For many of us, both moonless and moon-full nights simply aren't bright enough to stimulate the retina's cone cells responsible for detail and color vision. At low light levels, a different group of light-sensing cells called

rods go to work.

Rod cells are seriously sensitive, able to detect a single photon of light, but they lack the ability to see color

and detail. On a moonless night away from city lights, the nightscape is painted in shades of gray, charcoal black, and bony whites.

Things aren't so simple when the Moon is out, something you can see for yourself this week as the gibbous Moon waxes to full by Sunday night.

Moonlight is essentially sunlight reflected from the Moon's surface. Makes sense. Because that

surface is asphalt-black, it returns only 11% of the light lavished upon it by our star. Light striking the Moon's

ubiquitous pulverized dust is actually somewhat redder than sunlight, but we don't see this with our eyes because

it's offset by all the other colors contained in moonlight. A high-riding Moon gleams with silvery-white

radiance.

But what about the landscape at right?

As we touched on earlier, a casual glance outdoors on a bright moonlit night reveals a world of grays. Color

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doesn't jump to mind, except for maybe blue. Blue? You've probably noticed a favorite trick used by painters and movie directors alike to simulate moonlight. Add blue! With movies, it's done by taping in the daytime with

a filter over the lens.

Rods may be colorblind, but they're most sensitive to blue-green light. Could this be the reason behind

moonlight blues? In their paper titled Modeling Blue Shift in Moonlit Scenes by Rod Cone Interaction, Saad M. Khan and Sumanta N. Pattanaik (University of Central Florida) hypothesize that rod signals "bleed" into adjacent blue cones to create the illusion of blue under a moonlit sky.*

I experimented with my own perception of color at night during both half-moon and full phases over the past month. Snow was present and helped to amplify the light. Regarding blue, I found that overall color or lack

thereof depended on my suggestibility. Knowing the landscape was to supposed to appear blue according to TV tradition, I easily saw pale blue snow and a general blueness to the air, trees and brush. But when I wasn't paying attention, the landscape seemed humdrum gray, white, and black — no color — unless I looked

closely, but more of that in a minute.

Okay, so much for overall color. What about individual colors under a full Moon? You may have read that

colors aren't perceptible in moonlight, but experiments during both summer and winter (with and without the bump from snow) prove the contrary, at least to this pair of eyes.

During last month's full Moon, which stood high in Taurus, I could see the red of a stop sign without difficulty.

Ditto for my green coat and the tall, brown weeds covering a nearby field. I only struggled with blue, which looked unusually pale, verging on white in the lighter hues and grey in the darker. While none of the colors jumped out, I saw each convincingly. At least around the time of full Moon, there's enough light to activate

the eye's cones, contrary to common belief.

Granted, there are individual differences in visual perception depending on your particular set of cones and

rods, but it's fascinating nonetheless to see how far you can expand your nighttime vision by conducting these simple experiments. If nothing else, you'll get a walk in the moonlight as reward for your efforts.

What will you see as the Moon goes a for high ride in Gemini this weekend? Is the landscape really blue? How clearly do specific colors stand out? Please drop us a line in Comments and share your perspective.

Source: Sky & Telescope Return to Contents

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Space Image of the Week

Vela Supernova Remnant

Image Credit & Copyright: CEDIC Team - Processing: Wolfgang Leitner

Explanation: The plane of our Milky Way Galaxy runs through this complex and beautiful skyscape.

At the northwestern edge of the constellation Vela (the Sails) the telescopic frame is over 10 degrees wide, centered on the brightest glowing filaments of the Vela Supernova Remnant, an expanding

debris cloud from the death explosion of a massive star. Light from the supernova explosion that created the Vela remnant reached Earth about 11,000 years ago. In addition to the shocked filaments of glowing gas, the cosmic catastrophe also left behind an incredibly dense, rotating stellar core,

the Vela Pulsar. Some 800 light-years distant, the Vela remnant is likely embedded in a larger and older supernova remnant, the Gum Nebula

Source: APOD Return to Contents