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Space News Update — March 29, 2016 —

Contents

In the News

Story 1:

High Albedo Points to Huge Collision Forming Plutonian System

Story 2:

Japan’s Newest Space Telescope Goes Silent

Story 3:

Moons of Saturn May be Younger than the Dinosaurs

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. High Albedo Points to Huge Collision Forming Plutonian System

Pluto’s family of satellites. NASA’s New Horizons mission has resolved Pluto’s four small moons, shown in order of their

orbital distance from Pluto (from left to right). Nix and Hydra have comparable sizes (with equivalent spherical diameters

of ~40 km) and are much larger than Styx and Kerberos (both of which have equivalent spherical diameters of ~10 km).

All four of these moons are highly elongated and are dwarfed in size by Charon, which is nearly spherical with a diameter

of 1210 km. The scale bars apply to all images. Image by NASA/Johns Hopkins University Applied Physics

Laboratory/Southwest Research Institute

The high albedo (reflectivity) of some of Pluto’s moons supports the theory that those moons were formed as

a result of a collision, rather than being Kuiper Belt Objects (KBOs) that wandered too close and were

captured by Pluto’s gravity. Data supporting the collision theory came from NASA’s New Horizons spacecraft as

it flew by Pluto in July 2015.

The Pluto system is a complex one. Pluto has 5 moons: Charon, Styx, Nix, Kerberos, and Hydra. Charon is the

only moon that is tidally locked with Pluto, and the two are sometimes called a double dwarf planet. The

system’s barycenter lies between Pluto and Charon, though much closer to Pluto. The objects in the system

move in near-circular orbits, rather than ellipses.

Pluto and Charon were thought to have formed the same way the other planets formed in the Solar System;

by coalescing out of a ring of debris left over after the Sun formed. Then, it was thought, the other Plutonian

moons were captured from the Kuiper Belt. Pluto resides in the Kuiper Belt, so this made sense. Some of the

other moons in our Solar System, like Neptune’s Triton and Saturn’s Phoebe, are also thought to be captured

Kuiper Belt Objects (KBOs).

A competing theory for the formation of the Pluto system is the collision theory. This theory states that Pluto

and Charon did indeed coalesce out of the ring of debris around the Sun, and that Charon was itself a dwarf

planet. But a collision occurred after that, about 4 or 4.5 billion years ago, between Pluto and an object about

the same size as Pluto.

This collision left Pluto and Charon in their binary state, but created a circumbinary disk of debris out of which

the other 4 moons formed. There are competing versions of these theories, one of which suggests that all of

Pluto’s 5 moons were formed by this collision, and none coalesced out of the circumstellar disk of debris that

the other planets were formed from.

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New Horizons has delivered measurements and data showing that the albedo of Pluto’s 4 smallest moons is

much too high for captured KBOs. Their surface reflectivity is highly suggestive of a water-ice composition.

Measured KBOs have a geometric albedo of less than .20, while Styx, Nix, Hydra, and Kerberos have values of

.40, .57, .56, and .45 respectively. This points to the idea that the object that collided with Pluto 4 to 4.5

billion years ago had at least some icy surface layers.

Pluto’s 4 small moons, Styx, Nix, Kerberos, and Hydra, are all non-spheroidal. This also points to their origins

as conglomerated objects which formed from a collision-induced debris disk, rather than as captured Kuiper

Belt objects.

These results were published in the journal Science, on March 18th, 2016. They were gathered using the

Long-Range Reconnaissance Imager (LORRI), and the Multispectral Visible Imaging Camera (MVIC)

instruments on board New Horizons.

Half of the data from New Horizons’ visit to Pluto is yet to arrive, including data from the Linear Etalon

Imaging Spectral Array (LEISA). Scientists are hopeful that this data, and all the existing data which together

will take years to analyze, will answer some of the questions surrounding the formation of the Pluto system.

Source: Universe Today

_________________________________________________

Pluto: On Frozen Pond

Credits: NASA/JHUAPL/SwRI

Source: NASA Return to Contents

NASA’s New Horizons spacecraft spied several features on Pluto that offer evidence of a time millions or billions of years ago when – thanks to much higher pressure in Pluto’s atmosphere and warmer conditions on the surface – liquids might have flowed across and pooled on the surface of the distant world. “In addition to this possible former lake, we also see evidence of channels that may also have carried liquids in Pluto’s past,” said Alan Stern, Southwest Research Institute, Boulder, Colorado—principal investigator of New Horizons and lead author of the scientific paper. This feature appears to be a frozen, former lake of liquid nitrogen, located in a mountain range just north of Pluto’s informally named Sputnik Planum. Captured by the New Horizons’ Long Range Reconnaissance Imager (LORRI) as the spacecraft flew past Pluto on July 14, 2015, the image shows details as small as about 430 feet (130 meters). At its widest point the possible lake appears to be about 20 miles (30 kilometers) across.

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2. Japan’s Newest Space Telescope Goes Silent

Artist’s concept of the Hitomi observatory. Credit: JAXA/Akihiro Ikeshita

Japan has lost contact with the newly-launched Hitomi space telescope, and ground observations indicate the

satellite has shed debris and may be tumbling in orbit more than 350 miles above Earth.

Ground controllers lost contact with the Hitomi black hole observatory at the start of a planned

communications pass around 0740 GMT (3:40 a.m. EDT) Sunday, the Japan Aerospace Exploration Agency

said in a statement.

Shortly before the loss of communications with Hitomi, the U.S. military’s space tracking radars detected five

objects in the vicinity of the satellite. The Joint Space Operations Center, the U.S. military command charged

with monitoring objects in orbit, said Monday the debris came off the Hitomi spacecraft around 0142 GMT

Sunday (9:42 p.m. EDT Saturday).

The Hitomi mission, also known as Astro-H, launched Feb. 17 aboard a Japanese H-2A rocket. The mission

was supposed to last at least three years.

Engineers have been unable to determine the health of the satellite since the sudden disruption in

communications, JAXA said, although ground controllers received a brief signal from Hitomi. “While the cause

of communication failure is under investigation, JAXA received short signal from the satellite, and is working

for recovery,” the space agency said in a statement.

JAXA established an emergency response headquarters to investigate the satellite’s communications failure

and attempt to recover the mission.

The detection of debris from Hitomi indicates an “energetic event” occurred aboard the satellite, according to

Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics who expertly tracks

satellite activity.

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But McDowell said it is too early to write Hitomi’s obituary, citing other space science missions that have come

back from the brink of failure to resume normal operations, such as the NASA-ESA SOHO solar observatory.

“‘Debris’ doesn’t mean Hitomi’s in little pieces,” McDowell wrote on Twitter. “It means little pieces have come

off it. Satellite might be basically intact, we don’t know.” An explosion inside the Hitomi spacecraft, a fuel or

gas leak, or a collision with a piece of space junk could have generated the debris and put the satellite in a

tumble.

Hitomi was still in a functional testing phase when Sunday’s anomaly occurred. Normal science observations

were supposed to begin later this year.

Hitomi is Japan’s sixth X-ray astronomy satellite, following up on a series of missions since 1979 that resolved

the universe’s most energetic regions.

X-rays emitted by hot plasma hold clues about the inner workings of the mysterious black holes, the lives of

galaxies, the structure of galactic clusters and where clumps of dark matter may reside in the universe.

Formed by the powerful supernova explosions of old stars, black holes give off X-rays as they ingest matter,

sending beams through the universe that can only be detected by telescopes like the sensors aboard Hitomi.

The Hitomi observatory extended a boom to a length of 20 feet — more than 6 meters — soon after its Feb.

17 launch. The deployable bench hosts the craft’s hard X-ray imagers, while the rest of the mission’s

instruments reside in the satellite’s main body.

The mission’s core instrument is the Soft X-ray Spectrometer, or SXS, which contains a “micro-calorimeter”

developed jointly by Japanese and U.S. scientists. Chilled to 50 milliKelvin (minus 459.58 degrees Fahrenheit,

or minus 273.1 degrees Celsius), a fraction of a degree above absolute zero, the detectors were designed

to register X-ray photons and measure their energy with high sensitivity, collecting data that will tell

astronomers about the composition and velocity of the super-heated matter that produced the light.

Super-cold liquid helium and a series of mechanical and magnetic refrigerators were to keep a 36-pixel

detector array chilled for at least three years, cold enough to sense faint light from faraway objects.

JAXA officials reported the SXS instrument’s micro-calorimeter reached its super-cold operating temperature

Feb. 22, allowing Hitomi’s three-month test and calibration campaign to start.

The micro-calorimeter was to be the first sensor of its kind to make astronomical measurements in space. First

developed in the 1980s, the technology was supposed to fly aboard a NASA observatory that eventually

became Chandra, which launched in 1999, but cost concerns kept the sensor off the mission.

Earlier versions of the Soft X-ray Spectrometer launched on two Japanese X-ray missions in 2000 and 2005,

but the first was destroyed in a launch failure, and the second ran into trouble weeks after liftoff and ran out

of liquid helium coolant before observations began, rendering the instrument useless.

Scientists hoped for a better outcome this time. “We were very excited by the launch of Hitomi and looking

forward to the unprecedented high spectral resolution data from its X-ray calorimeter,” McDowell told

Spaceflight Now. “We’ve been trying to get one of these flying for two decades so its loss would be tragic.

Let’s hope JAXA can recover it.”

Hitomi’s X-ray sensors were designed to see cosmic phenomena invisible to the human eye, seeing through

veils of gas and dust that obscure observations with conventional telescopes.

Japan spent 31 billion yen, or about $270 million, on the Astro-H project, not counting contributions from the

United States, Canada and Europe.

Source: SpaceflightNow.com Return to Contents

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3. Moons of Saturn May be Younger than the Dinosaurs

SETI Institute Press Release

The new paper finds that Saturn’s moon Rhea and all other moons and rings closer to Saturn may be only 100 million

years old. Outer satellites (not pictured here), including Saturn’s largest moon Titan, are probably as old as the planet

itself. Image credit: NASA/JPL.

New research suggests that some of Saturn’s icy moons, as well as its famous rings, might be modern

adornments. Their dramatic birth may have taken place a mere hundred million years ago, more recent than

the reign of many dinosaurs.

“Moons are always changing their orbits. That’s inevitable,” says Matija Cuk, principal investigator at the SETI

Institute. “But that fact allows us to use computer simulations to tease out the history of Saturn’s inner moons.

Doing so, we find that they were most likely born during the most recent two percent of the planet’s history.

“While Saturn’s rings have been known since the 1600s, there’s still debate about their age. The

straightforward assumption is that they are primordial — as old as the planet itself, which is more than four

billion years. However, in 2012, French astronomers found that tidal effects — the gravitational interaction of

the inner moons with fluids deep in Saturn’s interior — are causing them to spiral to larger orbital radii

comparatively quickly. The implication, given their present positions, is that these moons, and presumably the

rings, are recent phenomena.

Cuk, together with Luke Dones and David Nesvorny of the Southwest Research Institute, used computer

modelling to infer the past dynamic behavior of Saturn’s icy inner moons. While our own moon has its orbit

around Earth to itself, Saturn’s many satellites have to share space with each other. All of their orbits slowly

grow due to tidal effects, but at different rates. This results in pairs of moons occasionally entering so-called

orbital resonances. These occur when one moon’s orbital period is a simple fraction (for example, one-half or

two-thirds) of another moon’s period. In these special configurations, even small moons with weak gravity can

strongly affect each other’s orbits, making them more elongated and tilting them out of their original orbital

plane.

By comparing present orbital tilts and those predicted by computer simulations, the researchers could learn

how much the orbits of Saturn’s moons grew. It turns out that for some of the most important satellites —

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Tethys, Dione and Rhea — the orbits are less dramatically altered than previously thought. The relatively small

orbital tilts indicate that they haven’t crossed many orbital resonances, meaning that they must have formed

not far from where they are now.

But how long ago was their birth? Cuk and his team used results from NASA’s Cassini mission to help answer

this question. The Cassini spacecraft has observed ice geysers on Saturn’s moon Enceladus. Assuming that the

energy powering these geysers comes directly from tidal interactions, and that Enceladus’ level of geothermal

activity is more or less constant, then the tides within Saturn are quite strong. According to the team’s

analysis, these would move the satellite by the small amount indicated by the simulations in only about

100 million years. This would date the formation of the major moons of Saturn, with the exception of more

distant Titan and Iapetus, to the relatively recent Cretaceous Period, the era of the dinosaurs.

“So the question arises, what caused the recent birth of the inner moons?” asks Cuk. “Our best guess is that

Saturn had a similar collection of moons before, but their orbits were disturbed by a special kind of orbital

resonance involving Saturn’s motion around the Sun. Eventually, the orbits of neighboring moons crossed, and

these objects collided. From this rubble, the present set of moons and rings formed.”

If this result is correct, Saturn’s bright rings may be younger than the heyday of the dinosaurs, and we are

fortunate to witness them today.

Saturn's moon Tethys, with its giant canyon Ithaca Chasma. It is proposed that Ithaca Chasma was opened by

strong tidal forces millions of years ago when Tethys was in an orbital resonance with the neighboring moon

Dione. Credit: NASA

Source: AstronomyNow Return to Contents

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The Night Sky

Source: Sky and Telescope Return to Contents

Tuesday, March 29

Jupiter's Great Red Spot should cross Jupiter's central meridian around 10:11 p.m. Eastern Daylight Time. At

10:54 p.m. EDT, Io disappears behind Jupiter's celestial-western limb. Io reappears from eclipse out of Jupiter's

shadow at 1:41 a.m. EDT, just off Jupiter's opposite limb. Subtract three hours from these times to get PDT.

Wednesday, March 30

Last-quarter Moon tonight (exact at 11:17 a.m. Thursday EDT). The Moon rises very late, around 2 a.m. local

time, with Mars and Saturn pointing down to it from the upper right.

Thursday, March 31

With the Moon out of the evening sky, try exploring the galaxy groups around Gamma Leonis (Algieba) in the

Sickle of Leo, using Sue French's Deep-Sky Wonders article, charts, and photos in the April Sky & Telescope, page

54.

Friday, April 1

Arcturus shines brightly in the east these evenings. The Big Dipper, high in the northeast, points its curving handle

lower right down toward it. Arcturus forms the pointy end of a long, narrow kite asterism formed by the brightest

stars of Bootes, the Cowherd. The kite is currently lying on its side to Arcturus's left. The head of the kite, at the

far left, is bent slightly upward. The kite is 23° long, about two fist-widths at arm's length.

This evening, telescope users along a narrow path from the Seattle/Vancouver area to Arkansas can watch for a

9.5-magnitude star (located 10° northwest of the Pleiades) to disappear for up to 9 seconds behind the invisibly

faint asteroid 2892 Filipenko.

The Gemini twins overlook Procyon very high in the southwest after dark this week. The three labeled stars here are part of the enormous Winter Hexagon. The star cluster left of Pollux near the edge is M44, the Beehive in Cancer. Akira Fujii

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ISS Sighting Opportunities (from Denver)

Date Visible Max Height Appears Disappears

Tue Mar 29, 9:20 PM 1 min 23° 10° above SW 23° above SW

Wed Mar 30, 8:28 PM 4 min 46° 11° above SSW 27° above E

Wed Mar 30, 10:05 PM < 1 min 11° 11° above W 11° above W

Thu Mar 31, 9:12 PM 4 min 36° 12° above W 29° above N

Fri Apr 1, 8:19 PM 6 min 67° 10° above WSW 10° above NE

Fri Apr 1, 9:58 PM < 1 min 14° 14° above NW 14° above NNW

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

NASA-TV Highlights (all times Eastern Time Zone)

Tuesday, March 29

8:30 a.m. - ISS Expedition 47 In-Flight Interview with SKY News for ESA with Flight Engineer Tim

Peake of the European Space Agency (all channels)

Wednesday, March 30

1 p.m. - The Smithsonian’s National Air & Space Museum Presents - “STEM in 30”- Mars Rovers –

Science on the Red Planet (NTV-1 (Public), NTV-2 (Education))

Thursday, March 31

12 p.m. - Coverage of the Launch of the ISS Progress 63 Cargo Craft to the ISS (Launch scheduled at

12:23 p.m. ET) (all channels)

Saturday, April 2

1 p.m. - Coverage of the Docking of the ISS Progress 63 Cargo Craft to the ISS (Docking scheduled at

2 p.m. ET) (Starts at 1:15 p.m.) (all channels)

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

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Space Calendar

Mar 29 - Comet 336P/McNaught Closest Approach To Earth (2.528 AU)

Mar 29 - Comet 4P/Faye At Opposition (3.827 AU)

Mar 29 - Comet 120P/Mueller At Opposition (4.276 AU)

Mar 29 - Aten Asteroid 2016 BC14 Near-Earth Flyby (0.025 AU)

Mar 29 - Apollo Asteroid 2016 EK156 Near-Earth Flyby (0.036 AU)

Mar 29 - Asteroid 4444 Escher Closest Approach To Earth (1.457 AU)

Mar 29 - Apollo Asteroid 2101 Adonis Closest Approach To Earth (1.981 AU)

Mar 29 - Joseph Taylor's 75th Birthday (1941)

Mar 30 - Cygnus CRS Orb-5 Antares Launch (International Space Station)

Mar 30 - Comet 11P/Tempel-Swift-LINEAR At Opposition (3.323 AU)

Mar 30 - Comet 156P/Russell-LINEAR At Opposition (3.865 AU)

Mar 30 - Aten Asteroid 2010 GD35 Near-Earth Flyby (0.039 AU)

Mar 30 - Aten Asteroid 2008 BX2 Near-Earth Flyby (0.049 AU)

Mar 30 - Apollo Asteroid 2016 EQ84 Near-Earth Flyby (0.071 AU)

Mar 30 - Asteroid 289586 Shackleton Closest Approach To Earth (1.064 AU)

Mar 30 - Asteroid 5703 Hevelius Closest Approach To Earth (1.912 AU)

Mar 30 - Robert Bunsen's 205th Birthday (1811)

Mar 31 - Progress MS-2 Soyuz U Launch (International Space Station 63P)

Mar 31 - 50th Anniversary (1966), Luna 10 Launch (USSR Moon Orbiter)

Mar 31 - Mercury Passes 0.6 Degrees From Uranus

Mar 31 - Asteroid 19398 Creedence Closest Approach To Earth (1.927 AU)

Mar 31 - Asteroid 990 Yerkes Closest Approach To Earth (2.244 AU)

Mar 31 - Asteroid 7336 Saunders Closest Approach To Earth (2.363 AU)

Mar 31 - Rene Descartes' 420th Birthday (1596)

Apr 01 - Cassini, Orbital Trim Maneuver #445 (OTM-445)

Apr 01 - Comet 233P/La Sagra Closest Approach To Earth (1.762 AU)

Apr 01 - Comet 110P/Hartley Closest Approach To Earth (2.567 AU)

Apr 01 - Asteroid 3 Juno Occults TYC 4991-00651-1 (11.9 Magnitude Star)

Apr 01 - Asteroid 1159 Granada Closest Approach To Earth (1.429 AU)

Apr 01 - Asteroid 7495 Feynman Closest Approach To Earth (1.520 AU)

Apr 01 - Asteroid 39566 Carllewis Closest Approach To Earth (1.769 AU)

Apr 01 - Asteroid 14702 Benclark Closest Approach To Earth (2.111 AU)

Source: JPL Space Calendar Return to Contents

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Food for Thought

90 Years Ago, the Liquid-Fueled Rocket Changed Space Travel Forever

Robert Goddard stands next to his first liquid-fueled rocket prior to its launch on March 16, 1926. Credits: Clark

University Robert H. Goddard Archive

Launches of liquid-fueled rockets may be relatively routine today, but 90 years ago, they were brand-new. In

fact, the first liquid-fueled rocket launched on March 16, 1926, under the direction of rocketry pioneer,

Massachusetts physics professor Robert Goddard. Goddard is the namesake of NASA’s Goddard Space flight

Center.

Dr. Goddard's first liquid-fueled rocket was small and did not fly all that high, but it marked a big change in

how rocketry is done. Prior to Goddard’s experimentation, rockets had not changed much in several centuries.

Chinese engineers invented them as war machines in the 13th century, using solid gunpowder as fuel. But

Goddard realized that liquid propellants offered a number of advantages over solid-fueled rockets. He began to

test rockets fueled by liquid gasoline and liquid oxygen.

Goddard, however, believed that liquid would offer more advantages than solid materials. Liquid rockets

provide more thrust per unit of fuel and allow engineers to specify how long the rocket will stay lit and how

fast it will burn its fuel.

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The new design posed a number of challenges. For instance, he had to find a way to mix the fuel with oxygen.

Otherwise it wouldn’t burn fast enough to produce the necessary thrust to lift the weight of the rocket. He also

had to find a mechanical solution to pressurize the fuel chamber so it would continually feed fuel to the

engine. Each solution he found brought with it a new challenge to solve.

"It looked almost magical as it rose, without any appreciably greater noise or flame, as if it said, 'I've been

here long enough; I think I'll be going somewhere else, if you don't mind,'" Goddard wrote in his journal the

next day, according to a NASA statement.

Goddard dreamed of seeing interplanetary travel made possible. It didn't happen while he was still alive — he

died in 1945 — but liquid rocketry became very important in space history.

Less than a century ago, astronomers relied entirely on ground-based observations to further scientific study.

Today, descendants of that first liquid-fueled rocket provide eyes on cosmic phenomena, unravel mysteries of

the early universe, and even take a closer look at what makes our own planet tick.

The first satellite, Sputnik, was launched in 1957 using a rocket that in part used liquid fuel. Liquid fuel was

also used for the massive Saturn V rocket that took astronauts to the moon in the 1960s and 1970s. Liquid

remains the fuel type of choice for human missions to this day; because the burn can be controlled, it is safer

than solid rocket propellants.

Other rockets with liquid fuels in one or more stages include the European Ariane 5 (which will launch NASA's

James Webb Space Telescope), Russia's Soyuz boosters, United Launch Alliance's Atlas V and Delta booster

family, and SpaceX's Falcon 9 rocket, among many others.

In his lifetime and after his death, Goddard received more than 200 patents for his inventions. One of his

major works included inventing multistage rockets, which are a foundation for just about every spaceflight

today. They allow a rocket to have multiple fuel tanks and engines, which are discarded as the rocket gets

higher in the atmosphere.

“The U.S. failed to recognize the full potential of his [Goddard's] work until after his death — in fact, some of

his ideas about reaching outer space were ridiculed during his lifetime," NASA wrote in the same statement.

"But the first liquid-fueled rocket flight was as significant to space exploration as the Wright brothers' first

flight was to air travel , and 90 years later, his patents are still integral to spaceflight technology."

Sources: Space.com and NASA Return to Contents

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Space Image of the Week

Hickson 91 in Piscis Austrinus

Image Credit & Copyright: CHART32 Team, Processing - Johannes Schedler

Explanation: Scanning the skies for galaxies, Canadian astronomer Paul Hickson and colleagues identified

some 100 compact groups of galaxies, now appropriately called Hickson Compact Groups (HCGs). This sharp

telescopic image captures one such galaxy group, HCG 91, in beautiful detail. The group's three colorful spiral

galaxies at the center of the field of view are locked in a gravitational tug of war, their interactions producing

faint but visible tidal tails over 100,000 light-years long. Their close encounters trigger furious star formation.

On a cosmic timescale the result will be a merger into a large single galaxy, a process now understood to be a

normal part of the evolution of galaxies, including our own Milky Way. HCG 91 lies about 320 million light-

years away in the constellation Piscis Austrinus. But the impressively deep image also catches evidence of

fainter tidal tails and galaxy interactions close to 2 billion light-years distant.

Source: NASA APOD Return to Contents