Space News Updatespaceodyssey.dmns.org/media/59786/snu_10212014.pdfSpace News Update — October 21, 2014 ... hydrogen-hunting neutron spectrometer and its laser altimeter, which measured

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Space News Update — October 21, 2014 —

Contents

In the News

Story 1:

MRO Spies Tiny, Bright Nucleus During Comet Flyby of Mars

Story 2:

First Photos of Water Ice on Mercury Captured by NASA Spacecraft

Story 3:

Hubble Telescope Finds Potential Kuiper Belt Targets for New Horizons Pluto Mission

Departments

The Night Sky

ISS Sighting Opportunities

NASA-TV Highlights

Space Calendar

Food for Thought

Space Image of the Week

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1. MRO Spies Tiny, Bright Nucleus During Comet Flyby of Mars

High resolution image pairs made with HiRISE camera on MRO during Comet Siding Spring’s closest approach to Mars on

October 19. Shown at top are images of the nucleus region and inner coma. Those at bottom were exposed to show the

bigger coma and the beginning of a tail. Credit: NASA/JPL/Univ. of Arizona

Not to be outdone by the feisty Opportunity Rover, the HiRISE camera on NASA’s Mars Reconnaissance

Orbiter (MRO) turned in its homework this evening with a fine image of comet C/2013 Siding Spring taken

during closest approach on October 19.

The highest-resolution images were acquired by HiRISE at the minimum distance of 85,750 miles (138,000

km). The image has a scale of 453 feet (138-m) per pixel.

The top set of photos uses the full dynamic range of the camera to accurately depict brightness and detail in

the nuclear region and inner coma. Prior to its arrival near Mars astronomers estimated the nucleus or comet’s

core diameter at around 0.6 mile (1 km). Based on these images, where the brightest feature is only 2-3 pixels

across, its true size is shy of 1/3 mile or 0.5 km. The bottom photos overexpose the comet’s innards but reveal

an extended coma and the beginning of a tail extending to the right.

To photograph a fast-moving target from orbit, engineers at Lockheed-Martin in Denver precisely pointed and

slewed the spacecraft based on comet position calculations by engineers at JPL. To make sure they knew

exactly where the comet was, the team photographed the comet 12 days in advance when it was barely bright

enough to register above the detector’s noise level. To their surprise, it was not exactly where orbital

calculations had predicted it to be. Using the new positions, MRO succeeded in locking onto the comet during

the flyby. Without this “double check” its cameras may have missed seeing Siding Spring altogether!

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Meanwhile, the Jet Propulsion Lab has released an annotated image showing the stars around the comet in

the photo taken by NASA’s Opportunity Rover during closest approach. From Mars’ perspective the comet

passed near Alpha Ceti in the constellation Cetus, but here on Earth we see it in southern Ophiuchus not far

from Sagittarius.

“It’s excitingly fortunate that this comet came so close to Mars to give us a chance to study it with the

instruments we’re using to study Mars,” said Opportunity science team member Mark Lemmon of Texas A&M

University, who coordinated the camera pointing. “The views from Mars rovers, in particular, give us a human

perspective, because they are about as sensitive to light as our eyes would be.”

After seeing photos from both Earth and Mars I swear I’m that close to picturing this comet in 3D in my mind’s

eye. NASA engineers and scientists deserve a huge thanks for their amazing and successful effort to turn

rovers and spacecraft, intended for other purposes, into comet observatories in a pinch and then deliver

results within 24 hours. Nice work!

Source: Universe Today

All Three NASA Mars Orbiters Healthy After Comet Flyby

All three NASA orbiters around Mars confirmed their healthy status Sunday after each took shelter behind Mars

during a period of risk from dust released by a passing comet.

Mars Odyssey, Mars Reconnaissance Orbiter and the Mars Atmosphere and Volatile Evolution (MAVEN) orbiter

all are part of a campaign to study comet C/2013 A1 Siding Spring and possible effects on the Martian

atmosphere from gases and dust released by the comet. The comet sped past Mars today much closer than

any other known comet flyby of Mars or Earth.

Source: JPL Return to Contents

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2. First Photos of Water Ice on Mercury Captured by NASA Spacecraft

A view of the crater Prokofiev on Mercury. The crater is the largest one on the planet’s north pole area to have “radar-

bright” material, a probable sign of ice. 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).

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

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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.

Source: Space.com and Universe Today Return to Contents

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3. Hubble Telescope Finds Potential Kuiper Belt Targets for New Horizons Pluto

Mission

This is an artist’s impression of a Kuiper Belt object (KBO), located on the outer rim of our solar system at a staggering

distance of 4 billion miles from the Sun. A HST survey uncovered three KBOs that are potentially reachable by NASA’s

New Horizons spacecraft after it passes by Pluto in mid-2015. Image Credit: NASA, ESA, and G. Bacon (STScI)

Peering out to the dim, outer reaches of our solar system, NASA’s Hubble Space Telescope has uncovered

three Kuiper Belt objects (KBOs) the agency’s New Horizons spacecraft could potentially visit after it flies by

Pluto in July 2015.

The KBOs were detected through a dedicated Hubble observing program by a New Horizons search team that

was awarded telescope time for this purpose.

“This has been a very challenging search and it’s great that in the end Hubble could accomplish a detection –

one NASA mission helping another,” said Alan Stern of the Southwest Research Institute (SwRI) in Boulder,

Colorado, principal investigator of the New Horizons mission.

The Kuiper Belt is a vast rim of primordial debris encircling our solar system. KBOs belong to a unique class of

solar system objects that has never been visited by spacecraft and which contain clues to the origin of our

solar system.

The KBOs Hubble found are each about 10 times larger than typical comets, but only about 1-2 percent of the

size of Pluto. Unlike asteroids, KBOs have not been heated by the sun and are thought to represent a pristine,

well preserved deep-freeze sample of what the outer solar system was like following its birth 4.6 billion years

ago. The KBOs found in the Hubble data are thought to be the building blocks of dwarf planets such as Pluto.

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The New Horizons team started to look for suitable KBOs in 2011 using some of the largest ground-based

telescopes on Earth. They found several dozen KBOs, but none was reachable within the fuel supply available

aboard the New Horizons spacecraft.

“We started to get worried that we could not find anything suitable, even with Hubble, but in the end the

space telescope came to the rescue,” said New Horizons science team member John Spencer of SwRI. “There

was a huge sigh of relief when we found suitable KBOs; we are ‘over the moon’ about this detection.”

Following an initial proof of concept of the Hubble pilot observing program in June, the New Horizons Team

was awarded telescope time by the Space Telescope Science Institute for a wider survey in July. When the

search was completed in early September, the team identified one KBO that is considered “definitely

reachable,” and two other potentially accessible KBOs that will require more tracking over several months to

know whether they too are accessible by the New Horizons spacecraft.

This was a needle-in-haystack search for the New Horizons team because the elusive KBOs are extremely

small, faint, and difficult to pick out against a myriad background of stars in the constellation Sagittarius,

which is in the present direction of Pluto. The three KBOs identified each are a whopping 1 billion miles

beyond Pluto. Two of the KBOs are estimated to be as large as 34 miles (55 kilometers) across, and the third

is perhaps as small as 15 miles (25 kilometers).

The New Horizons spacecraft, launched in 2006 from Florida, is the first mission in NASA’s New Frontiers

Program. Once a NASA mission completes its prime mission, the agency conducts an extensive science and

technical review to determine whether extended operations are warranted.

The New Horizons team expects to submit such a proposal to NASA in late 2016 for an extended mission to fly

by one of the newly identified KBOs. Hurtling across the solar system, the New Horizons spacecraft would

reach the distance of 4 billion miles from the sun at its farthest point roughly three to four years after its July

2015 Pluto encounter. Accomplishing such a KBO flyby would substantially increase the science return from

the New Horizons mission as laid out by the 2003 Planetary Science Decadal Survey.

Source: NASA Return to Contents

Two potential targets

for the New Horizons mission emerge in

these Hubble Space Telescope multiple-

exposure images. Both

are about four billion miles (6.4 billion

kilometers) away. NASA, ESA, SwRI,

JHU/APL, and the New

Horizons KBO Search Team.

Source: Universe Today

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The Night Sky

Source: Sky and Telescope Return to Contents

Tuesday, October 21

A challenge observation: as dawn brightens on

Wednesday morning the 22nd, binoculars or a

telescope may already show Mercury below the

thin crescent Moon very low in the east, as

shown here. Look about a half hour before

sunrise.

Mercury is not only low but faint: a tiny crescent

only magnitude 2.1. If you succeed, this may be

the thinnest you ever see Mercury as a

crescent: about 10% sunlit.

Wednesday, October 22

Jupiter's moon Io fades away into eclipse by

Jupiter's shadow around 2:43 a.m. Thursday

morning EDT (11:43 p.m. Wednesday evening

PDT). A small telescope is all you need to

watch. Io is the satellite just west of the planet

at the time.

Thursday, October 23

A partial eclipse of the Sun happens this

afternoon for most of North America. Seen from

the eastern half of the continent, the Sun sets

while the partial eclipse is still in progress.

Westerners get to see the whole thing. Eastern

New England misses out.

While we're at it, here's a preview of the great

total solar eclipse that will cross the United

States diagonally in less than three years:

Americans Will See Total Solar Eclipse in 2017.

Friday, October 24

As the stars come out this week, Deneb is

nearly straight overhead for skywatchers at mid-

northern latitudes. Brighter Vega is west of the

zenith. Altair is slightly farther from the zenith

toward the south.

The farther north and west you are, the deeper

Thursday afternoon's partial solar eclipse will become. Credit: Jay Anderson

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ISS Sighting Opportunities (from Denver)

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

NASA-TV Highlights (all times Eastern Time Zone)

Tuesday, October 21

11 a.m. - Unberthing and Release of the SpaceX/Dragon CRS-4 Cargo Craft from the ISS (all channels)

Wednesday, October 22

9 a.m. - Coverage of ISS Expedition 40 Russian Spacewalk # 40 (all channels)

Thursday, October 23

8:25 a.m. - ISS Expedition 41 In-Flight Event for ESA with Flight Engineer Alexander Gerst (all channels)

1:45 p.m. - ISS Expedition 41 In-Flight Event with NASA Flight Engineer Barry Wilmore (all channels)

Friday, October 24

6:15 p.m. - Video B-Roll of Orbital Sciences/Cygnus CRS-3 Processing (all channels)

6:45 p.m. - Coverage of the Launch of Orbital Sciences’ Antares Rocket and the Cygnus Cargo Ship to the

ISS (Launch scheduled at 7:52 p.m. ET) (all channels)

9:30 p.m. - Orbital Sciences/Cygnus CRS-3 Post-Launch News Conference – WFF (all channels)

Watch NASA TV online by going to the NASA website. Return to Contents

Date Visible Max Height Appears Disappears

Tue Oct 21, 8:03 PM 2 min 23° 10 above NW 23 above NNW

Wed Oct 22, 7:14 PM 3 min 22° 11 above NNW 20 above NE

Thu Oct 23, 8:01 PM 2 min 44° 10 above NW 44 above NW

Fri Oct 24, 7:12 PM 4 min 46° 10 above NW 31 above E

Sat Oct 25, 6:27 PM 1 min 21° 21 above ENE 11 above E

Sat Oct 25, 8:01 PM 1 min 33° 22 above W 33 above SW

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Space Calendar

Oct 21 - Express AM-6 Proton M-Briz M Launch

Oct 21 - Orionids Meteor Shower Peak

Oct 21 - Comet P/2014 M4 (PANSTARRS) At Opposition (1.429 AU)

Oct 21 - Comet C/2014 R4 (Gibbs) Perihelion (1.813 AU)

Oct 21 - Comet 286P/Christensen At Opposition (2.146 AU)

Oct 21 - Comet 41P/Tuttle-Giacobini-Kresak At Opposition (4.116 AU)

Oct 21 - Comet PANSTARRS (C/2014 S1) Closest Approach To Earth (7.611 AU)

Oct 21 - Asteroid 2010 VQ Near-Earth Flyby (0.027 AU)

Oct 21 - Asteroid 2340 Hathor Near-Earth Flyby (0.048 AU)

Oct 21 - Asteroid 10377 Kilimanjaro Closest Approach To Earth (1.710 AU)

Oct 21 - Asteroid 3834 Zappafrank Closest Approach To Earth (2.027 AU)

Oct 21 - Asteroid 5405 Neverland Closest Approach To Earth (2.030 AU)

Oct 22 - Asteroid 3674 Erbisbuhl Occults HIP 42472 (6.7 Magnitude Star)

Oct 22 - Asteroid 2014 RQ17 Near-Earth Flyby (0.031 AU)

Oct 22 - Asteroid 3066 McFadden Closest Approach To Earth (1.258 AU)

Oct 22 - Asteroid 2933 Amber Closest Approach To Earth (1.543 AU)

Oct 22 - Asteroid 1279 Uganda Closest Approach To Earth (1.571 AU)

Oct 22 - Asteroid 2521 Heidi Closest Approach To Earth (2.005 AU)

Oct 22 - Asteroid 8373 Stephengould Closest Approach To Earth (3.156 AU)

Oct 23 - Partial Solar Eclipse, Visible from Eastern United States

Oct 23 - Kondor-E 1 Strela Launch

Oct 23 - Comet PANSTARRS (C/2014 S1) At Opposition (7.611 AU)

Oct 23 - Asteroid 2014 SC324 Near-Earth Flyby (0.003 AU)

Oct 24 -Cygnus CRS Orb-3/ Flock-1d 1-26/ Arkyd-3 Antares-130 Launch (International Space Station)

Oct 24 - Chang'e 5 CZ-3Z Launch (China Moon Orbiter)

Oct 24 - Meridian 7 Soyuz 2-1A-Fregat Launch

Oct 24 - Cassini, Titan Flyby

Oct 24 - MESSENGER, Orbital Change Maneuver

Oct 24 - Comet C/2014 S3 (PANSTARRS) At Opposition (1.235 AU)

Oct 24 - Comet 81P/Wild At Opposition (3.480 AU)

Oct 24 - Asteroid 12410 Donald Duck Closest Approach To Earth (1.448 AU)

Oct 25 - Moon Occults Saturn

Oct 25 - Comet C/2013 A1 (Siding Spring) Perihelion (1.399 AU)

Oct 25 - Comet 125P/Spacewatch At Opposition (3.210 AU)

Source: JPL Space Calendar Return to Contents

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Food for Thought

Milky Way Ransacks Nearby Dwarf Galaxies, Stripping All Traces of Star-Forming

Gas

Artist's impression of the Milky Way. It’s hot halo appears to be stripping away the star-forming atomic hydrogen from its

companion dwarf spheroidal galaxies. Credit: NRAO/AUI/NSF

Astronomers using the National Science Foundation’s Green Bank Telescope (GBT) in West Virginia, along with

data from other large radio telescopes, have discovered that our nearest galactic neighbors, the dwarf

spheroidal galaxies, are devoid of star-forming gas, and that our Milky Way Galaxy is to blame.

These new radio observations, which are the highest sensitivity of their kind ever undertaken, reveal that

within a well-defined boundary around our Galaxy, dwarf galaxies are completely devoid of hydrogen gas;

beyond this point, dwarf galaxies are teeming with star-forming material.

The Milky Way Galaxy is actually the largest member of a compact clutch of galaxies that are bound together

by gravity. Swarming around our home Galaxy is a menagerie of smaller dwarf galaxies, the smallest of which

are the relatively nearby dwarf spheroidals, which may be the leftover building blocks of galaxy formation.

Further out are a number of similarly sized and slightly misshaped dwarf irregular galaxies, which are not

gravitationally bound to the Milky Way and may be relative newcomers to our galactic neighborhood.

“Astronomers wondered if, after billions of years of interaction, the nearby dwarf spheroidal galaxies have all

the same star-forming ‘stuff’ that we find in more distant dwarf galaxies,” said astronomer Kristine Spekkens,

assistant professor at the Royal Military College of Canada and lead author on a paper published in the

Astrophysical Journal Letters.

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Previous studies have shown that the more distant dwarf irregular galaxies have large reservoirs of neutral

hydrogen gas, the fuel for star formation. These past observations, however, were not sensitive enough to

rule out the presence of this gas in the smallest dwarf spheroidal galaxies.

By bringing to bear the combined power of the GBT (the world’s largest fully steerable radio telescope) and

other giant telescopes from around the world, Spekkens and her team were able to probe the dwarf galaxies

that have been swarming around the Milky Way for billions of years for tiny amounts of atomic hydrogen.

“What we found is that there is a clear break, a point near our home Galaxy where dwarf galaxies are

completely devoid of any traces of neutral atomic hydrogen,” noted Spekkens. Beyond this point, which

extends approximately 1,000 light-years from the edge of the Milky Way’s star-filled disk to a point that is

thought to coincide with the edge of its dark matter distribution, dwarf spheroidals become vanishingly rare

while their gas-rich, dwarf irregular counterparts flourish.

There are many ways that larger, mature galaxies can lose their star-forming material, but this is mostly tied

to furious star formation or powerful jets of material driven by supermassive black holes. The dwarf galaxies

that orbit the Milky Way contain neither of these energetic processes. They are, however, susceptible to the

broader influences of the Milky Way, which itself resides within an extended, diffuse halo of hot hydrogen

plasma.

The researchers believe that, up to a certain distance from the galactic disk, this halo is dense enough to

affect the composition of dwarf galaxies. Within this “danger zone,” the pressure created by the million-mile-

per-hour orbital velocities of the dwarf spheroidals can actually strip away any detectable traces of neutral

hydrogen. The Milky Way thus shuts down star formation in its smallest neighbors.

"These observations therefore reveal a great deal about size of the hot halo and about how companions orbit

the Milky Way," concludes Spekkens.

Source: National Radio Astronomy Observatory Return to Contents

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Space Image of the Week

Rosetta's Selfie Image Credit: ESA/Rosetta/Philae/CIVA

Explanation: This Rosetta spacecraft selfie was snapped on October 7th. At the time the spacecraft was

about 472 million kilometers from planet Earth, but only 16 kilometers from the surface of comet

67P/Churyumov-Gerasimenko.

Looming beyond the spacecraft near the top of the frame, dust and gas stream away from the comet's curious

double-lobed nucleus and bright sunlight glints off one of Rosetta's 14 meter long solar arrays. In fact, two

exposures, one short and one long, were combined to record the dramatic high contrast scene using the CIVA

camera system on Rosetta's still-attached Philae lander. Its chosen primary landing site is visible on the

smaller lobe of the nucleus. This is the last image anticipated from Philae's cameras before the lander

separates from Rosetta on November 12. Shortly after separation Philae will take another image looking back

toward the orbiter, and begin its descent to the nucleus of the comet.

Source: NASA APOD Return to Contents