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Space News Update — May 10, 2013 —

Contents

In the News

Story 1:

NASA troubleshoots ammonia coolant leak on station

Story 2:

Hubble Observes Planet-”Polluted” Dead Stars In Hyades

Story 3:

Shuttle astronaut to pilot Virgin's passenger spaceship

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 troubleshoots ammonia coolant leak on station

Flight controllers are monitoring an ammonia coolant leak in the International Space Station's left-side power

truss, NASA officials said late Thursday.

The leak, apparently located in the outboard port-six (P6) solar array truss segment, was reported by the station

crew around 11:30 a.m. EDT (GMT-4). Downlinked video, sources said, showed a stream of white flakes

dissipating in the vacuum of space.

NASA officials said the crew was not in any danger.

The leak is in the system used to cool electronics associated with solar array power channel 2B, one of eight fed

by the station's huge solar panels. Ammonia flowing through a large radiator is used to carry away heat

generated by the array's batteries and electrical systems.

The coolant system requires at least 40 pounds of ammonia to operate normally. Based on the observed leak

rate, NASA said in a web update, the channel 2B coolant loop could drop below that level and shut down within

48 hours if nothing is done to resolve it.

In that case, the station's six-man crew would be forced to reconfigure the station's coolant loops, using a

different loop to cool at least some of the channel 2B systems.

While the crew would lose redundancy in the cooling system, flight controllers do not believe any major

systems would have to be shut down to reduce cooling requirements.

The station is equipped with spare parts for the coolant system and the U.S. astronauts are trained for possible

spacewalk repair jobs. But as of this writing, it is not known whether a spacewalk might be required at some

point or whether some other repair option might be implemented.

But a spacewalk would require two U.S. astronauts. At present, two U.S. astronauts, a Canadian flier and three

Russians are aboard the outpost. But NASA astronaut Thomas Marshburn, Canadian space station commander

Chris Hadfield and cosmonaut Roman Romanenko are scheduled to return to Earth late Monday U.S. time

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aboard a Russian Soyuz spacecraft.

"We don’t see anything technically that we can't overcome," astronaut Doug Wheelock radioed the crew from

Houston. "But we are still getting our arms fully around that issue."

This is not the first time a leak has been observed in the channel 2B system.

A slight 1.5-pound-per-year leak in the channel 2B cooling system was first noticed in 2007. During a 2011

shuttle visit, two spacewalking astronauts added eight pounds of ammonia to the reservoir to boost it back up to

a full 55 pounds. The plan at that time was to top off the system every four years or so to "feed the leak,"

replacing the lost ammonia as required.

But over the next few months, engineers saw the leak rate suddenly quadruple, either because something

changed at the original leak site or, more likely, because another leak developed elsewhere in the system.

On the assumption that the leak was in the solar array 2B coolant radiator, astronauts Sunita Williams and

Akihiko Hoshide staged a spacewalk Nov. 1, 2012, to reconfigure coolant lines and to deploy a spare radiator,

isolating the section of the loop where the leak was suspected.

The system operated normally until Thursday when the crew reported the visible leak. Whether the latest

problem is related to the earlier issue is not yet known.

The lion's share of the International Space Station's electrical power comes from four sets of dual-panel solar

arrays, two on the right side of a 357-foot-long truss and two on the left side.

Each set of solar arrays features two 115-foot-long panels that extended in opposite directions. The Russian

segment of the station taps into the U.S. power grid to supplement electricity generated by two relatively small

solar panels on the Zvezda command module.

The two U.S. arrays at the far left end of the station's integrated power truss -- the port six, or P6 arrays -- feed

power to electrical channels 2B and 4B. The P6 set of arrays, like its three counterparts, routes power from the

solar panels directly into the station's electrical grid during daylight passes, at the same time charging dual sets

of batteries that take over during orbital darkness.

Each power channel generates between 150 and 160 volts of direct current, but downstream equipment near the

center of the power truss -- equipment that uses a separate cooling system -- steps that down to 125 volts DC for

use by the station's internal systems.

To keep the power generation components cool, each of the four sets of arrays uses two independent coolant

loops that circulate ammonia through cold plates to carry heat out to a single shared radiator that extends from

each module. The photo-voltaic radiator weighs 1,650 pounds and is made up of seven panels measuring 6 feet

by 11 feet.

The space station can operate without the full complement of cooling channels, but the total loss of a coolant

loop would require a significant reconfiguration to prevent electrical systems on the affected loop from

overheating.

Source: CBS News “Space Place” Return to Contents

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2. Hubble Observes Planet-”Polluted” Dead Stars In Hyades

For those of us who practice amateur astronomy, we’re very familiar with the 150 light-year distant Hyades star

cluster – one of the jewels in the Taurus crown. We’ve looked at it countless times, but now the NASA/ESA

Hubble Space Telescope has taken its turn observing and spotted something astronomers weren’t expecting –

the debris of Earth-like planets orbiting white dwarf stars. Are these “burn outs” being polluted by detritus

similar to asteroids? According to researchers, this new observation could mean that rocky planet creation is

commonplace in star clusters.

“We have identified chemical evidence for the building blocks of rocky planets,” said Jay Farihi of the

University of Cambridge in England. He is lead author of a new study appearing in the Monthly Notices of the

Royal Astronomical Society. “When these stars were born, they built planets, and there’s a good chance they

currently retain some of them. The material we are seeing is evidence of this. The debris is at least as rocky as

the most primitive terrestrial bodies in our solar system.”

So what makes this an uncommon occurrence? Research tells us that all stars are formed in clusters, and we

know that planets form around stars. However, the equation doesn’t go hand in hand. Out of the hundreds of

known exoplanets, only four are known to have homes in star clusters. As a matter of fact, that number is a

meager half percent, but why? As a rule, the stars contained within a cluster are young and active. They are

busy producing stellar flares and similar brilliant activity which may mask signs of emerging planets. This new

research is looking to the “older” members of the cluster stars – the grandparents which may be babysitting.

To locate possible candidates, astronomers have employed Hubble’s Cosmic Origins Spectrograph and focused

on two white dwarf stars. Their return showed evidence of silicon and just slight levels of carbon in their

atmospheres. This observation was important because silicon is key in rocky materials – a prime ingredient on

Earth’s list and other similar solid planets. This silicon signature may have come from the disintegration of

asteroids as they wandered too close to the stars and were torn apart. A lack of carbon is equally exciting

because, while it helps shape the properties and origins of planetary debris, it becomes scarce when rocky

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planets are formed. This material may have formed a torus around the defunct stars which then drew the matter

towards them.

“We have identified chemical evidence for the building blocks of rocky planets,” said Farihi. “When these stars

were born, they built planets, and there’s a good chance they currently retain some of them. The material we are

seeing is evidence of this. The debris is at least as rocky as the most primitive terrestrial bodies in our solar

system.”

Ring around the rosie? You bet. This leftover material swirling around the white dwarf stars could mean that

planet formation happened almost simultaneously as the stars were born. At their collapse, the surviving gas

giants may have had the gravitational “push” to relocate asteroid-like bodies into “star-grazing orbits”.

“We have identified chemical evidence for the building blocks of rocky planets,” explains Farihi. “When these

stars were born, they built planets, and there’s a good chance that they currently retain some of them. The signs

of rocky debris we are seeing are evidence of this — it is at least as rocky as the most primitive terrestrial

bodies in our Solar System. The one thing the white dwarf pollution technique gives us that we won’t get with

any other planet detection technique is the chemistry of solid planets. Based on the silicon-to-carbon ratio in our

study, for example, we can actually say that this material is basically Earth-like.”

What of future plans? According to Farihi and the research team, by continuing to observe with methods like

those employed by Hubble, they can take an even deeper look at the atmospheres around white dwarf stars.

They will be searching for signs of solid planet “pollution” – exploring the white dwarf chemistry and analyzing

stellar composition. Right now, the two “polluted” Hyades white dwarfs are just a small segment of more than a

hundred future candidates which will be studied by a team led by Boris Gansicke of the University of Warwick

in England. Team member Detlev Koester of the University of Kiel in Germany is also contributing by using

sophisticated computer models of white dwarf atmospheres to determine the abundances of various elements

that can be traced to planets in the Hubble spectrograph data.

“Normally, white dwarfs are like blank pieces of paper, containing only the light elements hydrogen and

helium,” Farihi said. “Heavy elements like silicon and carbon sink to the core. The one thing the white dwarf

pollution technique gives us that we just won’t get with any other planet-detection technique is the chemistry of

solid planets.”

The team also plans to look deeper into the stellar composition as well. “The beauty of this technique is that

whatever the Universe is doing, we’ll be able to measure it,” Farihi said. “We have been using the Solar System

as a kind of map, but we don’t know what the rest of the Universe does. Hopefully with Hubble and its

powerful ultraviolet-light spectrograph COS, and with the upcoming ground-based 30- and 40-metre telescopes,

we’ll be able to tell more of the story.”

And we’ll be listening…

Source: Universe Today Return to Contents

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3. Shuttle astronaut to pilot Virgin's passenger spaceship

Veteran space shuttle commander Rick Sturckow has joined

Virgin Galactic to pilot the company's suborbital passenger

spaceship, officials announced Tuesday.

Sturckow and Michael Masucci, a former U.S. Air Force test pilot,

will conduct training and flight testing at Virgin Galactic's base in

Mojave, Calif.

"Viewing the Earth from space is such a unique and unforgettable

experience," Sturckow said in a statement. "I'm excited to be a part

of the Virgin Galactic team that is revolutionizing access to space, making this opportunity a possibility for all."

Sturckow, 51, flew on four space shuttle missions - twice as pilot and two times as commander. All four flights

focused on the assembly of the International Space Station.

The retired U.S. Marine Corps colonel spent 51 days in space. Sturckow last flew on the STS-128 mission,

commanding the shuttle Discovery in 2009 to help outfit the space station for a six-person crew.

One of Sturckow's last positions at NASA was as deputy chief of the agency's Astronaut Office, flying weather

reconnaissance for the last few space shuttle missions.

Masucci has more than 9,000 flight hours in more than 70 different types of airplanes and gliders, according to

Virgin Galactic. He is a graduate of the U.S. Air Force Test Pilot School and served as combat pilot on the U-2

spy plane and instructor on the F-16, T-38 and gliders.

After his Air Force career, Masucci flew for Xojet Inc., a private charter airline company.

"I am pleased to have these two incredibly accomplished pilots join us during this important time as we embark

on a series of important rocket-powered flight tests for SpaceShipTwo, ultimately testing the vehicle in space,"

said George Whitesides, Virgin Galactic's president and CEO, in a statement. "Their collective experience and

outstanding performance in various demanding environments will make them invaluable assets to the Virgin

Galactic team."

Sturckow and Masucci join a cadre of Virgin Galactic pilots flying the company's SpaceShipTwo rocket plane

and WhiteKnightTwo carrier aircraft.

Virgin Galactic plans a series of increasingly ambitious test flights this year after completing SpaceShipTwo's

first rocket-powered flight over Mojave on April 29.

"It seems like we hit it out of the park," Whitesides said in an interview last week.

The 16-second burn of SpaceShipTwo's hybrid rocket motor, built by Sierra Nevada Corp., appeared smoother

than some of its ground tests, Whitesides said.

Virgin Galactic expects to conduct its first SpaceShipTwo flight above 100 kilometers, the internationally-

recognized boundary of space, before the end of 2013. Commercial service in New Mexico could begin next

year.

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Before then, pilots and engineers at Virgin and Scaled Composites, builder of SpaceShipTwo and its

mothership, aim to "expand the envelope" of the spacecraft, pushing it higher and faster and verifying its

performance if something goes wrong, Whitesides said.

"In the next few flights, it will be a matter of simply burning the motor longer," Whitesides told Spaceflight

Now. "Toward the second half of the year, we might open it up into some off-nominal configurations."

On the regulatory front, Whitesides said Virgin Galactic will submit its license request to the Federal Aviation

Administration soon for passenger flights. The FAA must respond to the request within 180 days by law, he

said.

Whitesides said Virgin Galactic has signed up approximately 570 passengers to fly on the six-seat space plane,

which provides riders with several minutes of weightlessness and an astronaut's-eye view of Earth for a price

tag of about $200,000.

Source: Spaceflight Now Return to Contents

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The Night Sky

Source: Sky & Telescope Return to Contents

Friday, May 10

Young Moon challenge. Have you ever

seen a crescent Moon as young as about 24

hours? Not many people have, and in North

America, now's your chance. Look just above

the west-northwest horizon starting 15

minutes after sunset. The Moon is way down

there close to Venus. Binoculars help, then try

with your naked eyes.

Note the time, then determine how long this is

since new Moon occurred yesterday at 8:28

p.m. Eastern Daylight Time. The difference

tells the Moon's current age. Does it break

your personal record?

Saturday, May 11

The beautiful 2-day-old crescent Moon

hangs below Jupiter in the western evening

twilight, as shown above. Look below the

Moon for twinkly Aldebaran on its way out

for the year.

Sunday, May 12

Jupiter and the 3-day-old Moon shine in the

west at dusk, as shown above. Look for

Betelgeuse still twinkling to their left.

Monday, May 13

Three zero-magnitude stars shine after dark

in May: Arcturus high in the southeast, Vega

much lower in the northeast, and Capella in

the northwest. They appear so bright because

each is at least 60 times as luminous as the

Sun, and they are all relatively nearby: 37, 25,

and 42 light-years from us, respectively.

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ISS Sighting Opportunities For Denver:

SATELLITE LOCAL DURATION MAX ELEV APPROACH DEPARTURE

DATE/TIME (MIN) (DEG) (DEG-DIR) (DEG-DIR)

No Sightings for Denver through May 13

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

NASA-TV Highlights (all times Eastern Daylight Time)

May 10, Friday

4 p.m. - ISS Status Briefing (time subject to change) - JSC (All Channels)

May 12, Sunday

3:40 p.m. - ISS Expedition 35/36 Change of Command Ceremony (Hadfield hands over ISS command to

Vinogradov) - JSC (All Channels)

May 13, Monday

2:30 p.m. - NASA Marks the 40th Anniversary of Skylab and Life Off Earth - HQ (All Channels)

3:30 p.m. - ISS Expedition 35 Farewells and Hatch Closure Coverage (hatch closure scheduled at 3:50 p.m.

ET) - JSC (All Channels)

6:45 p.m. - ISS Expedition 35/Soyuz TMA-07M Undocking Coverage (undocking scheduled at 7:08 p.m. ET) -

JSC (All Channels)

9:15 p.m. - ISS Expedition 35/Soyuz TMA-07M Deorbit Burn and Landing Coverage (Deorbit burn scheduled

at 9:37 p.m. ET, landing near Dzhezkazgan, Kazakhstan scheduled at 10:31 p.m. ET) - JSC via Kazakhstan (All

Channels)

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

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Space Calendar

May 10 - [May 09] Annular Solar Eclipse (Visible From Austrlia, Pacific Ocean)

May 10 - Comet C/2013 H1 (La Sagra) Closest Approach To Earth (1.725 AU)

May 10 - Comet P/2012 TK8 (Tenagra) Perihelion (3.091 AU)

May 10 - Asteroid 21 Lutetia Occults 2UCAC 40336209 (12.4 Magnitude Star)

May 10 - [May 10] Asteroid 2013 JR7 Near-Earth Flyby (0.023 AU)

May 10 - Asteroid 1988 TA Near-Earth Flyby (0.034 AU)

May 10 - Asteroid 1322 Coppernicus Closest Approach To Earth (1.148 AU)

May 10 - Lecture: Radar Imaging of Near Earth Asteroids, Pasadena, California

May 11 - Comet C/2013 G6 (Lemmon) Closest Approach To Earth (1.241 AU)

May 11 - Asteroid 498 Tokio Closest Approach To Earth (1.795 AU)

May 11 - Richard Feynman's 95th Birthday (1918)

May 12 - Asteroid 5020 Asimov Closest Approach To Earth (1.174 AU)

May 12 - Asteroid 4416 Ramses Closest Approach To Earth (1.420 AU)

May 12 - Asteroid 10044 Squyres Closest Approach To Earth (1.928 AU)

May 12 - Asteroid 2246 Bowell Closest Approach To Earth (2.728 AU)

May 13 - Comet 114P/Wiseman-Skiff Perihelion (1.575 AU)

May 13 - Comet 61P/Shajn-Schaldach At Opposition (3.844 AU)

Source: JPL Space Calendar Return to Contents

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Food for Thought

Water on moon, Earth have a common source

Water inside the Moon's mantle came from primitive meteorites, new

research finds, the same source thought to have supplied most of the

water on Earth. The findings raise new questions about the process

that formed the Moon.

The Moon is thought to have formed from a disc of debris left when a

giant object hit the Earth 4.5 billion years ago, very early in Earth's

history. Scientists have long assumed that the heat from an impact of

that size would cause hydrogen and other volatile elements to boil off

into space, meaning the Moon must have started off completely dry.

But recently, NASA spacecraft and new research on samples from the Apollo missions have shown that the

Moon actually has water, both on its surface and beneath.

By showing that water on the Moon and on Earth came from the same source, this new study offers yet more

evidence that the Moon's water has been there all along.

"The simplest explanation for what we found is that there was water on the proto-Earth at the time of the giant

impact," said Alberto Saal, associate professor of Geological Sciences at Brown University and the study's lead

author. "Some of that water survived the impact, and that's what we see in the Moon."

The research was co-authored by Erik Hauri of the Carnegie Institution of Washington, James Van Orman of

Case Western Reserve University, and Malcolm Rutherford from Brown and published online in Science

Express.

To find the origin of the Moon's water, Saal and his colleagues looked at melt inclusions found in samples

brought back from the Apollo missions. Melt inclusions are tiny dots of volcanic glass trapped within crystals

called olivine. The crystals prevent water escaping during an eruption and enable researchers to get an idea of

what the inside of the Moon is like.

Research from 2011 led by Hauri found that the melt inclusions have plenty of water — as much water in fact

as lavas forming on the Earth's ocean floor. This study aimed to find the origin of that water. To do that, Saal

and his colleagues looked at the isotopic composition of the hydrogen trapped in the inclusions. "In order to

understand the origin of the hydrogen, we needed a fingerprint," Saal said. "What is used as a fingerprint is the

isotopic composition."

Using a Cameca NanoSIMS 50L multicollector ion microprobe at Carnegie, the researchers measured the

amount of deuterium in the samples compared to the amount of regular hydrogen. Deuterium is an isotope of

hydrogen with an extra neutron. Water molecules originating from different places in the solar system have

different amounts of deuterium. In general, things formed closer to the sun have less deuterium than things

formed farther out.

Saal and his colleagues found that the deuterium/hydrogen ratio in the melt inclusions was relatively low and

matched the ratio found in carbonaceous chondrites, meteorites originating in the asteroid belt near Jupiter and

thought to be among the oldest objects in the solar system. That means the source of the water on the Moon is

primitive meteorites, not comets as some scientists thought.

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Comets, like meteorites, are known to carry water and other volatiles, but most comets formed in the far reaches

of the solar system in a formation called the Oort Cloud. Because they formed so far from the sun, they tend to

have high deuterium/hydrogen ratios — much higher ratios than in the Moon's interior, where the samples in

this study came from.

"The measurements themselves were very difficult," Hauri said, "but the new data provide the best evidence yet

that the carbon-bearing chondrites were a common source for the volatiles in the Earth and Moon, and perhaps

the entire inner solar system."

Recent research, Saal said, has found that as much as 98 percent of the water on Earth also comes from

primitive meteorites, suggesting a common source for water on Earth and water on Moon. The easiest way to

explain that, Saal says, is that the water was already present on the early Earth and was transferred to the Moon.

The finding is not necessarily inconsistent with the idea that the Moon was formed by a giant impact with the

early Earth, but presents a problem. If the Moon is made from material that came from the Earth, it makes sense

that the water in both would share a common source. However, there's still the question of how that water was

able to survive such a violent collision.

"The impact somehow didn't cause all the water to be lost," Saal said. "But we don't know what that process

would be."

It suggests, the researchers say, that there are some important processes we don't yet understand about how

planets and satellites are formed.

"Our work suggests that even highly volatile elements may not be lost completely during a giant impact," said

Van Orman. "We need to go back to the drawing board and discover more about what giant impacts do, and we

also need a better handle on volatile inventories in the Moon."

Source: Eureka Alert Return to Contents

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Space Image of the Week

An Awesome Annular Eclipse! Images and Videos from Earth and Space

A spectacular annular eclipse of the Sun was witnessed across Australia and the southern Pacific region early

today. Morning dawned mostly clear across the Australian continent, and those who journeyed out to meet the

antumbra of the Moon as the Sun rose across the Great Sandy Desert and the Cape York Peninsula were not

disappointed. The rest of us watched worldwide on as Slooh and a scattering of other ad-hoc broadcasts

delivered the celestial event to us via the web.

See more images and videos on Universe Today.

Source: Universe Today Return to Contents